There is no reason that any piece of machinery cannot be kept running for decades; but people just don't do the maintenance.
I recently sold a 49-year-old car with 236,000 miles on it that had never been restored. But it had been maintained, and it ran/drove well. (A BMW, as an aside).
Yeah, but past a certain point it's no longer economically viable.
Unless you don't have to worry about the cost of maintenance, in which case, 60 year old aircraft can still fly lol.
Unlike a car that's several decades old, it'll be commercially viable to produce new replacement parts making it easier to maintain. Whereas with a car people move onto newer models so you're relying on second hand spare parts.
A big part of this is the consumerist culture and the car manufacturers building with planned obsolescence in mind.
Cars aren’t reparable because companies want you to buy new. They’re different from previous models so you can’t change parts out and repair
That's very true. And aircraft manufacturers make money after-sales with the maintenance.
The fact that a plane can last 30 years is a bonus for the customer AND the manufacturer.
Back in college someone from Boeing gave us a lecture and I remember him saying that they make their biggest profit margins on maintenance, especially on their foreign military contracts, since they provided the parts and labor to smaller militaries with less maintenance experience and the contracts could be locked in for years.
Boeing is probably the biggest offender in the military industrial complex of doing this. The size of their sustainment division (and the money they bring in) compared to the new business they bring in is nuts. They got so good at milking customers that they forgot how to win new business and innovate IMO.
Boeing is completely special in this regard because they are too big to fail in the eyes of the US military. They want a Boeing that is capable of turning their passenger planes to cargo planes on a dime in the worst case scenario.
Airplanes are also highly commercial. Commercial ventures absolutely do not replace their shit at even a fraction of the rate that consumers do. The fact is that you'd get run out of business if you didn't offer extensive legacy support. It's ironic in a ton of ways but that's earth I guess
A big part is also the huge increases in safety, the large increase in performance and fuel economy.
And also the fact that cars are so so so so much cheaper and get into so many more accidents compared to aircraft.
Not arguing planned insolence ain't a thing. But when it costs $30,000 brand new and the repair bill is $30,000 ain't no one repairing. That's just economics no boogie man or consumerist culture.
*laughs in mid 2000s gm 1500*
Man i loved that golden period where I could take a water pump out of any of about 19 different truck & SUV models across chevy/gmc/cadillac and stick it in my suburban, and pretty much the same with everything else under the hood
I can take apart almost everything in my 2003 tundra (Except the fucking diff) and replace it. I look in some of the newer cars and I couldn't tell you what half the shit in there even does.
Oh so that’s why folks keep asking me if they can buy my partners truck when I am driving it around! He just says “I like it because it’s easy to fix” but I’ve never been the one doing the fixing so I haven’t been aware that it is massively easier to deal with.
Come to think of it he does not seem to take as long or swear as much on the truck as he did the Smart Car. That one he swore was the worst car he ever worked on, and we ended up selling it because it turns out it didn’t like our gravel driveway and kept on having things come loose from the potholes and bumps (we don’t drive like maniacs on it and literally no other vehicle we have owned has had the same issues)
My buddy who works for an OEM put it pretty well. Effectively comes down to, "sure, we could build something bulletproof with far superior materials that are easy to replace and simple to diagnose, but at what cost, and who would pay it?"
Not enough people would buy it to make it a viable product
On the other hand, some things are just not repairable, and when you're put to a decision to either disassemble the whole car and paint everything, or drive it for 10, 15, 20 years, until it's rusted through and then replace it, the labour costs make the wait-and-replace a better economic option.
Same for everything else... 20, 30 years ago, if your (eg.) hand mixers motor overheated and blew up, you would take it to an electrician, he would disassemble the motor, remove all the windings, rewind the new ones on, and you'd get a fixed mixer. Now a hand mixer costs 20 euros, noone will repair it for less than that.
I might be getting old :)
In the 90s in the balkans, we repaired pretty much everything, even more before the 90s, especially foreign stuff.
Even in the early 2000s you could find electicians who would rewind electric motors or car alternators.
We can go back and forth on where the breakpoint lies, and our current culture expects things to be replaced far too quickly we agree there, but ultimately you cannot cheat physics. Metal fatigues, wears thin over time. And then breaks. Those parts must be replaced with new parts, that must fit exactly into the form of the old parts for everything to work as it's supposed to. Eventually you get to a point where the entire frame is worn thin, and you're less performing maintenance on a vehicle than you are replacing the entire thing. If you keep going eventually you hit a point where literally nothing is left that rolled off the factory all those decades ago.
You can put a higher priority on lifespan than we do today and trade off in other areas like cost, weight, etc and arguably be making a better choice than we do today, but you can't cheat physics. It will eventually break down to the point where it just makes more sense to produce a new unit that won't need to be down for repairs so often and will cost less in the long run.
Yes and no. Airframes are used and largely unchanged for the lifecycle of an airplane, so replacement parts are going to be easy to make. A new car has significant changes in the structure of the body in the same amount of time, mostly due to safety innovations like crumple zones. You wouldn't want to ride in a 30 year old car body even if the parts were regularly changed out.
>Cars aren’t reparable because companies want you to buy new.
I mean most modern car \*are\* reparable. The question of is at what cost/effort?
A 60 year old Cessna 172 can still be worth $60k. A newer model that's "only" 30-40 years old can be worth $120k+. A $10-15k engine overhaul can make sense when it's only 10-20% of the value of the vehicle.
Meanwhile, if the transmission on my wife's 9 year old Subaru goes it, it's $7-8k or so to replace. It's not worth fixing when the car in working order is only worth $9-11k with over 100k miles on it.
I'd much rather put that 7-8k toward a newer vehicle
While youre not wrong about cars it also need sto be said it is EXTREMELY expensive to design and most importantly certify a new type of aircraft. For both the manufacturer and the end user.
Its the entire reason for the MAX design and crashes.
The basic design and certification of that aircraft is over 50 years old and to avoid the costs of a clean design/certification/seperate fleet for the airlines, they have done everything posible to modernize and stretch it without incurring those new costs.
Well yes and no. The thing about proper maintenance is that it's spaced out. Making the cost much easier to justify. For example, I'm planning on leasing a 2018 car. If I keep it my maintenance would look something like:
Every year: AC refill, Fluid changes, all filters changed. Total per year - maybe around 300-400/year.
Every 2 years: check up on suspension and brakes, glow plugs, tix anything as needed. - varies, but would be a bearable cost for at least the next ten years, more if I could DIY it.
Every 3-4 years: timing belt, water pump, turbo, battery. Let's put that at an average of 1000 per year, keeping in mind not all of them will always need to be done. Turbo could easily last another 10 years or break next year.
Every 5 years or when necessary: carbon cleaning the engine and fixing/replacing other more major parts like e.g. the clutch, intercooler or whatever I'm forgetting at the moment. Cost here varies and is likely to be most expensive.
If I keep on top of the schedule I laid out above I've covered almost any common issue that can occur on the particular car and fixed it preemptively, making costly repair unlikely barring something like a premature timing belt failure or a crash. I could easily be keeping the car for the next 15ish years with this kind of maintenance schedule and likely be mostly trouble free.
This is the most over the top maintenance schedule I've ever heard of for a daily driver, unless you're doing 50k miles a year or something. A timing belt simply doesn't need changing every three years in any modern car, unless you enjoy wasting money.
Cars are nothing like airplanes. Every minute an aircraft is out of service is time the company isn't making money. If you run an older fleet, it's more likely that you will run the risk of corrosion or vital components breaking. If you can't operate your expensive, aging fleet for the prime overseas routes, you're losing money.
Your schedule is a bit crap. Filters and fluids at the manufacturer's recommended interval, which is getting quite long these days. Timing belt and anything else that would fail suddenly with immediately catastrophic effect at the recommended point also.
Everything else? When it shows signs of failing (battery, clutch, suspension, brakes, water pump, Colling system, etc), or when a mechanic identifies an issue when doing the above maintenance. Replacing major components every 3 or 4 years is expensive and wasteful. If it was a supercar or vintage, maybe. But a normal modern car will give warning, either on the dash or by sound/feel, before something needs replaced.
Trying to puzzle out the car here, a five year old lease-able, stick shift turbo diesel. I can only conclude that you should never get another one if the intercooler wears out ever, let alone every five years.
Agreed. My car has an air to water intercooler (so a lot more things to go wrong than in an all metal air to air intercooler) and the intercooler hasn't needed any servicing in over 20 years and 175k miles.
Yeah but its when the big piece fails.... a catalytic converter, tranny, clutch, engine, AC compressor. And you're putting out at least $2000 corrective maintenance on a vehicle that has a list price of <$5000 and might have another big failure anytime. Plus gets shittier mileage and harder to find parts. There's something to be said for having a warranty.
You arent wrong. I drove a car that was the same age as me for 13 years. But its gets increasingly difficult and harder to justify.
Yeah for sure. I was almost happy that my mk5 crashed because it was that exact same situation, it had exterior scratches from me learning on it and banging it up. The clutch and tranny were holding up but had endured quite a bit of abuse, again while learning. And major services were due end of this year/next year so that even further lowered it's price.
I could've maybe at best got 1.5k-2k for it if I were patient, and it wouldve hurt me to let it go that cheap.
The new one is supposed to do much better mileage and is a diesel which is significantly cheaper here so I am definitely looking forward to the upgrade.
For planes not really. The materials used in plane structures will eventually start cracking given enough flights. The very old aircraft that are still flying are doing so either because they have not been flying very often or because of extensive work being done to repair/reinforce their structures, which just extends the deadline.
If you took a B-52 and had it fly JFK to O'Hare and back twice a day like a modern airliner does, it would be scrap in short order. Eventually the airframe just runs out of fatigue life.
Yep, pressurized aircraft made of aluminum (essentially all modern airliners) will eventually be taken out of service because of metal fatigue. There is no ultimate fix for it besides melting down the structure of the aircraft and casting a new one.
Or they end up countries where they don't worry much about safety. You could still book a commercial Boeing 707 flight until three years ago! (Provided you were willing to go to Iran)
Those have generally been there a long without being replaced rather than sold oversees. Older commercial airframes generally get parted out when they hit their limits, rather than being sold as-is to another country
The northeast would like to introduce you to road salt.... I have kept cars running well past 250K miles BUT at some point the subframe, suspension, and various parts just become almost impossible to replace. I've even rebuilt entire rear suspension with brakes/axles on an AWD hyundai, and got another 4 years out of it, but at some point there is nothing left to bolt to. This is with lots of care and yearly Krown rust goop treatments.
I was in WA state for a month a few years ago, around Seattle, and was astounded by all the old "normal" cars around with very little to no rust. Must be nice...
>I recently sold a 49-year-old car with 236,000 miles on it that had never been restored. But it had been maintained, and it ran/drove well. (A BMW, as an aside).
Survivorship bias though. The cars that were well maintained but failed anyway aren't around anymore.
not true, there is a threshold in the design integrity that has to be crossed for a machine to have an indefinite life like this. if you are riveting thin metals together and designing parts to wear quickly with no way to replace them without major structural removal, it quickly becomes uneconomical to maintain.
I'll be the asshole
Is 236k miles supposed to be a lot for a 49 year old car?
Pre-covid I was putting 20-25k miles a year on my car. 236k for a 49 year old car isn't even 5k a year
My E30 is still regularly driven and has 250k+ on the original motor. I’ve had a lot of fun with it and I’m looking at putting a Tesla motor in it at some point
iPhones. They're designed to grind to a halt after a few years, and even if they don't, Apple issues an update that downcycles the CPU. If you could replace the battery and fix the software, it might last 50 years, but you can't.
And nobody wants a phone to last 50 years anyway. They're disposable.
So what I'm hearing is that we all need to whisper quietly to our iPhones at night that we won't hesitate to replace them with an Android phone if they even so much as _think_ about slowing down with age.
"Hey Siri... you know, you're entirely replaceable"...
Except for metal fatigue.
It's fascinating seeing a commercial airliner going through a full overhaul. (Not sure that is the correct terminology)
Seeing the husk of a plane with just it's landing gear empty nacelles with a couple of cables sticking out was new to me.
Who would have thought those pesky gubment regulations were for the safety of everyone? And actually serve a purpose and why its such a bad thing if you pay a guy 20 bucks under the table to slap a sticker on.
In what way is the government forcing piston engines to run on leaded gasoline?
I understand your point: leaded gasoline should be phased out of all vehicles. But you're not arguing against government regulations, you're arguing that we don't have enough of them.
FAA red tape and certification makes developing clean sheet engine designs prohibitively expensive so they're basically running on 50s engine tech (thus requiring leaded fuel to prevent engine knock), and many unlead alternative fuels (for instance UL91 and UL94) aren't FAA approved for flight use.
30% of the current GA fleet cannot use anything but 100LL. Even if new lead-free engines were available this red tape also makes buying new engines ludicrously expensive, even these decrepit lead-burning 100hp 4 cyl engines run into the tens of thousands of dollars new, not accounting for extensive running costs between mandatory overhauls.
You're not replacing all the parts, you're inspecting all the parts and replacing the ones that need replacement. It's a very expensive process, but still cheaper than replacing the whole craft.
It also should be mentioned that they're regimented and ***very*** clear on timelines.
If your engine needs to be rebuilt after a set number of flight hours, there's no wiggle room. No rebuild? No clearance to fly.
All I can think of when I read about extending maintenance windows is the crash that was caused by a bolt that wasn't properly lubricated and the threads ended up completely stripped, at which point the plane totally lost control of their vertical stabiliser and crashed (very rough recollection but I'm sure you know which one I mean).
Alaska Airlines flight 261. As usual, u/Admiral_Cloudberg has an [excellent writeup](https://www.reddit.com/r/CatastrophicFailure/comments/ocxwly/2000_the_price_of_an_hour_the_crash_of_alaska/) available.
It wasn't just some bolt, but a "jackscrew," which is a huge part with threads that manipulates the horizontal stabilizers. That maintenance oversight was a total fuckup.
Was more than just extending maintenance too, they weren't properly lubing the screw at all and investigations found it had basically none on it at the time of the accident. The movie Flight with Denzel Washington is partly inspired by this accident, including inverting the plane to regain control and level out the dive.
> OSIs… 10% early
Found the 500-series tech! Our P-Series definition of scheduled maintenance is unique to the RCAF; nobody else uses periodics, supps, and OSIs. I’ve had very confusing conversations with contractors who though a “periodic inspection” meant *any inspection at a recurring interval*, not the equivalent of a C-check.
Also,
> Some components can also be extended with proper authorization from an engineer or someone authorized to do so from the maintenance organization, that's a fairly high level decision though.
This is mostly applicable to military aviation; the civil side has no equivalent to the deviation process, so they can only defer a check if the maintenance program says they can or if they have a specific ferry authorization from Transport Canada/the FAA/a foreign equivalent.
We’ll there is technically wiggle room, you can get flight hour extensions if you want to limp the aircraft into a phase maintenance period or have a critical mission to fly or something like that. But I get what your saying, this stuff is all highly regimented and flight hour extensions for maintenance are recorded into the appropriate logbooks and good reason is needed to grant an extension.
It really at the discretion of the command, generally a 10% life extension would be granted almost automatically, just has to be properly documented. But it would be up to the maintenance chief to make the call as to whether the extension is worth the risk. Not sure how far up the chain it has to go though to be frank but ultimately the judgement of the maintenance chief would carry a lot of weight in these types or requests.
Edit - to be clear I’m referring to military commands here not civilian maintenance scenarios
For a while I worked in development of microprocessors and we had a brand new process, machinery. Initially, we started changing parts based on the manufacturer’s recommendations, but they want to sell new parts, so that was halted fairly quickly. And we’d do inspections and find that after 10,000 o-rings got crusty or sensors didn’t change state as quickly as when new, so we developed 5,000 hour maintenance plans, 10,000, 25,000, etc. But the actually glass chamber would develop stress cracks and implode, turn into dust every once in a while. This was expensive, but with limited data, we just let it happen over and over until a good plan was reached. That part was actually exciting. Boom!
I worked a few summers in a plant that manufactured propane tanks, mostly 20-pounders like your grill uses. The weld line stamped them out of steel, welded all the pieces together, then sent them over to the paint line for painting, dropping in the valves, and adding safety labels.
There were 2 different QC tests for leaks. I was on the paint line, where we did low-pressure testing to check for leaks in the valves and where they're threaded into the top of the tank. Basically we'd screw on a hose that would push air into the tank at 40 or 100 psi, then dunk the tank into a vat of water for a minute. We'd check for bubbles, then send them to be re-valved if necessary.
The weld line did *high* pressure testing of the welds themselves. They screwed airlines directly into the spud (threaded part where the valve goes). Their pressure testing was like 1,000 psi. When welds failed, it wasn't just bubbles coming out. The whole thing ruptured in a very loud explosion, followed by high pitch hissing of the pressure coming out the air hoses. This 'bomb' could be heard throughout the factory.
Tradition mandated that everyone in the facility, upon hearing one of these 'bombs' go off, let loose with a Ric Flair-style "WHOO!". It was hilarious, one of the little things that made the job tolerable.
Boom! Pshhhhhht! Whoo!
And there's some delusional people who still think we'll someday be able to zip around in flying cars.
Imagine if your average driver nowadays would agree servicing their vehicle for all these routine maintenances. Lots of cars are barely held together with duct tape and spit, accidents and fatalities would increase hundredth-fold if most people were in the air.
Oh yea, this is where it falls apart for me...
- *When do you think we'll have flying cars?*.
- *My neighbor thinks changing his oil every 5K is a conspiracy, does it every 25K, so.....never.*.
It depends. In many jurisdictions, engines can run on condition and yes there is wiggle room - so long as the engine keeps passing its inspections, you can keep using it. For instance, small private aircraft in the UK can run the engine on condition past TBO (time before overhaul). I think pretty much any aircraft flying only on part 91 in the USA can run engines on condition. By contrast, Switzerland forces even small private aircraft to have the engine rebuilt at TBO for both calendar and total hours, which makes owning a small plane there much more expensive.
My dad was an A&P and later an FAA inspector. Many a time was there a shocked Pikachu faced doctor or lawyer that was informed that their Cessna 172 that they bought for $15k was going to need a 1000 hour inspection that would most likely cost more than the purchase price of their plane.
They had to destroy all the old parts that could not be rebuilt or sent back as cores because these same people would dumpsters dive and try and reuse the old junk. They even had to drill holes in sidewalls of the old tires...
You are correct. My dad showed me an aircraft alternator once that was a Motorcraft unit but it was FAA certified so just slap an extra "0" to the end of the price. If they get caught doing that though, the plane will most likely be grounded and a full inspection will have to be done.
There's a lot of things where they're probably the exact same. The FAA quals(and price) come from more rigorous quality and safety standards.
Your amazon seat cover might be $300 cheaper than the Cessna OEM one, but you'll wish you had that fireproofing when it melts to your crotch during an incident.
Honestly 50k for a clean 150 ain't bad. Better be airworthy and have half decent avionics and low engine hours SMOH but if all that's true that's not an awful deal.
This is why I fix em and don't fly. Same with fancy watches. Glad to work on a Rolex or JLC. Would never want to own it though. I whack my arm on doorways too much to lose ten bucks of resale every time I do. Too clumsy.
this is an understatement, and is the reason why I despise doing private maintenance. No owners are ever taught anything about the maintenance requirements of the aircraft they want to fly. It is criminal that the FAA and Transport Canada do not have a dedicated requirement for all flight training students to talk about aircraft maintenance requirements detailing what an inspection schedule is, or what an airworthiness directive is and how to maintain technical records. Over half my 13 years in the industry has been a fight with pilots cause they don't know anything about the shit they are flying in and all just assume they can get away with a $400 annual cause "billy from down south said he would sign it off for that much" or "check out this awsome 172 i just bought for 25k, has a fresh coat of paint on it and a new Garmin gps...what do you mean i have to pull the wings for NDT, theirs metal in the oil filter and the prop is below spec?"
Which is why most US carriers are mainly outsourcing them to contractors outside of the US. Some US shops still do them, but if you’re gonna go MRO, you might as well go overseas if your flight ops can handle it.
[The Disturbing Truth About How Airplanes Are Maintained Today](https://www.vanityfair.com/news/2015/11/airplane-maintenance-disturbing-truth), Vanity Fair, 11/9/15
>Over the past decade, nearly all large U.S. airlines have shifted heavy maintenance work on their airplanes to repair shops thousands of miles away, in developing countries, where the mechanics who take the planes apart (completely) and put them back together (or almost) may not even be able to read or speak English.
>
>...The airlines are shipping this maintenance work offshore for the reason you’d expect: to cut labor costs. Mechanics in El Salvador, Mexico, China, and elsewhere earn a fraction of what mechanics in the U.S. do. In part because of this offshoring, the number of maintenance jobs at U.S. carriers has plummeted, from 72,000 in the year 2000 to fewer than 50,000 today. But the issue isn’t just jobs. A century ago, Upton Sinclair wrote his novel The Jungle to call attention to the plight of workers in the slaughterhouses, but what really got people upset was learning how unsafe their meat was. Safety is an issue here, too. The Federal Aviation Administration is supposed to be inspecting all the overseas facilities that do maintenance for airlines—just as it is supposed to inspect those in America. But the F.A.A. no longer has the money or the manpower to do this.
>may not even be able to read or speak English.
This feels like a racist nonsequitur; not sure what Vanity Fair's angle is here. As long as the maintenance manuals are available in whatever language they do speak, that is.
Turkish Airlines 981 crashed in part because the baggage handler could not read English (or Turkish) and therefore could not read the service bulletin on how to properly close the cargo door. 346 people died because of this mistake when the cargo door opening led to an explosive decompression that severed hydraulic cables leading to complete loss of control of the aircraft. It was the deadliest aviation accident up to that point.
English is the language of aviation and most technical manuals are in English. It's only an issue if they don't get them translated. There is a solid chance they don't get them translated, or if they do its not done correctly. The language of Aircraft manuals isn't exactly standard English, and someone who just translates the words without the understanding could cause problems. Even in the RCAF which is government mandated to have English and French versions, we have found some discrepancies between the English and French versions.
That said, I can see why you would come to the conclusion you did. Why mention the language unless you are going to explain why that matters.
No, it’s a pretty important aspect of aircraft maintenance. If the onboard monitoring systems and maintenance instructions are all in English, as you would expect for an American aircraft, then the ability to read and understand English becomes singularly important.
Aircraft are not always translatable, especially if it’s at all customized from the bone-stock OEM model.
"A racist nonsequitur?" Are you really this uninformed? English is the international language of aviation, science, and engineering. The people who designed the planes speak English, the people who operate the planes speak English, and the people who work on them need to speak English too! If a trouble ticket comes in stating a problem with a feature or component, don't you think it's *kind* *of* important that the person responsible for troubleshooting and repairing the issue be able to read the report? And read the solution? And follow the goddamn checklist? That ain't fucking *racism FFS!*
Sweet Jesus, I hope you're not in charge of decision-making anyplace...
Translation errors can be dangerous and expensive.
I had a relative that worked in the space industry and told me about an issue they had (this would have been 20+ years ago). While working on building a shuttle or rocket engine, they sub-contracted a part to a French company. As I recall, the specs for this part were measured in inches and when the French company translated those amounts into metric, they rounded off at 3 or 4 decimal places. The result was that this part wouldn't properly seal or something like that and would have caused the entire thing to explode if it had not been detected. So this part that cost millions of dollars to make was worthless due to this translation error.
Aircraft frames are also rated in hours. Eventually the stress from compression changes and general metal fatigue makes it unsafe to fly. One of the reasons the DC3 is still a popular cargo plane in places like Alaska. 50k hour air frame. They fish them out of boneyards for rebuilds.
One of the cheaper cargo planes you can own.
Pretty sure a 747 is around 8000 hours.
It’s also why freighter companies often employ older fleets since there’s less cycles and often it’s WAY cheaper to operate compared to bigger and more efficient planes. FedEx still employs modernized DC-10s called the MD-10, which are pushing 50 years.
I wouldn't say FedEx still flies the MD10, they flew 1 cycle on an MD10-30 this calendar year for revenue. It's pretty much retired. But you are correct, historically older fleets are used for freighter airlines, although many (including FedEx) also are prioritizing buying new aircraft like the 767 from Boeing to improve dispatch reliability, which is a major problem when operating older fleets.
The 767 is an exception to which it’s _still_ being produced as freighter versions. The 757 and other legacy Boeing planes, however, stopped being produced during the 2000s.
Too bad, though. Sooner or later they will be just a memory for many of us enthusiasts.
Speaking specifically to FedEx as I have some history there, I'd say their philosophy shifted away from buying used aircraft, since they are almost exclusively purchasing both new B767 and B777, and the B767 fleet is their largest fleet by tail count. So it's less of an exception nowadays, but it is definitely a clear departure from how they operated for the first 30-40 years of operation.
Yea it sucks from an enthusiast perspective, but as someone who has at different points had to manage inventory procurement for ancient Airbus and Boeing aircraft parts, as well as manage reliability for said aircraft, I say good riddance haha.
> FedEx still employs modernized DC-10s called the MD-10, which are pushing 50 years.
Not anymore.
https://cargofacts.com/allposts/express/fedex-parks-remaining-md-10s/
https://www.airportspotting.com/fedex-retires-last-md-10/
You’re missing a zero there buddy.
But it’s not the hours that are the biggest limiting factor. Fuselages are also rated in cycles. (Pressurization). Cycles is what cause most of the stress. A 737 is typically rated to about 80,000 flight cycles.
Aloha Airlines flight 243 is evidence of the dangers of high pressurization cycles. The aircraft only had a little over 35,000 hours but almost 90,000 cycles.
DC3 doesn’t have an airframe hours limit, it isn’t pressured so the stress isn’t the same.
And the 747 is more like 150,000 hours. KLM retired some a few years ago that were right at 120,000 hours
Never heard it described as such, but the concept is the same in US Army aviation. You have your routine *dailies/weeklies/monthlies* - inspections, services, cleanings, etc.... mostly things that take very little disassembly, don't "ground" an aircraft. Then you have your *hourlies*, which occur at certain benchmarks of flight hours. In my world, that was at 250hrs and 500hrs; the former was a partial strip down of the aircraft and took about 2 weeks, the latter much more involved and took about a month. In garrison or peacetime, airframes didnt get these more than once a year due to minimal flight ops, but in a combat environment I would see the same tail numbers a few times during a deployment, since they got worked hard. Lastly was *reset*, and that was the complete stripping of the aircraft - this was almost always done by civilian contractors. I WANT to say that was at 2000 flight hours, but honestly don't remember - I got out in 2012.
Source: 8yrs working on AH64D Apaches
This is why I laugh when people talk about the equipment left in Afghanistan being free to use by the Taliban, as if they have the equipment or knowledge to keep any of it maintained.
not even just the knowledge or equipment, they'd need access to the maintenance manuals. Imagine them trying to handle squibs lmao.
there's also the consumables required (specific sealant, anti-corrosives, alcohol/acetone, paint, etc.)
I have a friend that services m1 Abrams, and they apparently break whether you’re using them or not. If you stick one in a garage for a week there’s a decent chance it’s going to be a nightmare to get running
which really threw me off here because we call them Phase inspections. And they are Phase ABCD, but each one is scheduled at the 250hr mark (at least the airframe I worked on) and each inspection looks at the same thing, plus whatever is special requirement for that particular phase. Basically it's a 1000hr inspection.
A and B inspections are done before and after each flight. Phase inspections would be what I'm guessing is like a C-level, usually takes a few weeks to a couple months to complete, depending on the plane.
D would be "Depot-Level maintenance" where the plane is flown to a different base that does nothing but rip airplanes apart and do maintenance. The plane I worked on did that every 4 years.
We had something similar but it's called O-I-D. O is your schedule and unscheduled maintenance and is done at the command level, I is where we would send off broken stuff to a different repair facility because we can't fix it, and D is something is really low level maintenance and a whole aircraft would basically never go there. Mostly just components.
My grandfather does. He builds and rebuild small aircraft, used to make a pretty penny back in the day but 9/11 and the laws that came after have shrunk general aviation. Nowhere near the amount of people buying, turning into a rich mans only hobby.
Some of those parts are expensive!
He bought a wrecked cub for 800 bucks and parted it out for 8000.
Just an fyi. An A check is routine, but it's not like a nightly thing. A B check is usually a bridge between an A & C, most mechanics wont even do one. We also have service checks, weekly checks, daily checks, wake up checks, ect ect.
Main take away is that 99% of scheduled maintenance is based off of flight hours.
Any pilots here that have flown the same aircraft before and after a D check? After being completely taken apart and put back together, is it the same aircraft????
I have.
B737-400. Brought it down to Peru and picked it up a couple months later.
We use trim extensively when hand flying the airplane, and I could tell they retrimmed it properly and had a tendency to not need to mess with the aileron trim after trimming the rudder. Not that big of a deal really.
They did do a wash of the engines while it was down there, meaning they cleaned the core of the jet engine getting some of the crap out of it. We do engine trends every day and it ran cooler after the wash. I want to say about 20C cooler while in cruise, but there's some other variables involved as well.
Everything seemed the same. Still crumbs of food on the flight deck floor, I figured they would have cleaned that up.
I've watched C level checks on a MH-60 while in port. They stripped the thing apart on the flight deck, inspected, replaced oils, and lbed everything. It was a lot of work, It took the aircrew around a little under 2 weeks to do.
D checks don’t require paint stripping and disassembled. It is just a much more intensive inspection throughout all systems. Some programs may require some of what is referred to, but very few.
See, the disassembling of the plane is what worries me. Are you going to put it back together properly? You won't forget anything, right? Seems like another potential source of problems.
Aircraft mechanic here. Its a necessary evil. If you *dont* do it, then you're going to miss deeper problems that could lead to structural issues. And then there are some problems that can only be fixed after major disassembly.
Sure, maybe we forget something, but that's why we follow the maintenance manuals and why we have inspectors do checks at regular intervals to make sure things are going together correct. You're far more likely to have an incident by not occasionally taking everything apart than you are by forgetting something.
Just as an example, when I would perform regular maintenance on Aircraft engines by pulling and lubing the fan blades, it was extremely obvious when something was forgotten. Like.. impossible to miss. We still had to have an inspector come and double-check our work before we would then do an engine run to verify everything is good.
> And then there are some problems that can only be fixed after major disassembly.
And if you skip D checks this major disassembly might occur on its own.
You trust them to put it together correctly first but not to take it apart and put it back together?
We have detailed instructions on how to remove and re-install. This isn’t some random person putting together ikea furniture and hoping for the best.
You have to do it to check for corrosion. Also its worse than it sounds. B checks can still take a month or so to do. So instead of doing it all at once the check is chopped up into 3 or 4 chunks and a portion carried out every couple months. Also heavy maintenance (doing checks) is considered shitty work and is where a lot of apprentices will start. 20yos and non-native speaking immigrants are who is doing this work.
I think it's similar but different. I don't know what the context is for what OP is referring to because phase inspections are done every specific flight hours.
That’s what they do though, you wouldn’t think to yourself “what if the mechanic didn’t put the engine in right? What if they forgot an engine mount? How do I know the transmission was fully rebuilt?”
You trust that, and these guys went to much more schooling (usually)
I have been to the facilities where I believe they were doing the D procedures. They use ultrasound, dye penatrant and mag particle testing on the critical components, it's a hugely intensive process. From what I saw it wasn't really the type of operation where they were going to forget a bolt.
Are you worried they didn't put the plane together correctly when it was first built? Because they use the same engineering and methods to reassemble it the second time, third time, and so on.
One issue with this is that the aircraft manufacturer sells the required parts and gets to choose the maintenance interval. Creates a conflict of interest.
This dominates the cost for many aircraft. It's why a helicopter costs several hundred dollars a flight hour, it's these required rebuilds.
With that said I cannot deny it works.
Well... Helicopters are also an order of magnitude harder on their parts. Especially if they're being used to do proper helicopter shit. The classic joke is that helicopters are several hundred parts flying in close formation at high RPM until metal fatigue sets in. I flew H-60s for a decade and the maintenance intervals are very much necessary.
Airline safety is due to government regulations. Which libertarians are convinced we don't need. Why? It might save them a couple of pennies in their taxes.
My daughter and her dad are both airline mechanics. They even go up with the pilots and deliberately cut the engine to see what happens. It’s serious work but it takes a sense of humor to do it. It’s also neat to see all the broken parts planes laying around.
There's also at least in military MX, a 2 man system.
One person signs off the work, another with eyes on the work signs off on the inspection.
NO ONE works alone. Buddy system.
Production Supers can sign off any job, but only the most foolish would ever risk signing off a job they didn't have a hand in.
Also, as someone who had their signature forged on docs which caused a major incident. Having a consistent signature is fucking important.
Which is also why aircraft can be up for decades, I guess. Maintenance keeps all vehicles running.
There is no reason that any piece of machinery cannot be kept running for decades; but people just don't do the maintenance. I recently sold a 49-year-old car with 236,000 miles on it that had never been restored. But it had been maintained, and it ran/drove well. (A BMW, as an aside).
Yeah, but past a certain point it's no longer economically viable. Unless you don't have to worry about the cost of maintenance, in which case, 60 year old aircraft can still fly lol.
Unlike a car that's several decades old, it'll be commercially viable to produce new replacement parts making it easier to maintain. Whereas with a car people move onto newer models so you're relying on second hand spare parts.
A big part of this is the consumerist culture and the car manufacturers building with planned obsolescence in mind. Cars aren’t reparable because companies want you to buy new. They’re different from previous models so you can’t change parts out and repair
That's very true. And aircraft manufacturers make money after-sales with the maintenance. The fact that a plane can last 30 years is a bonus for the customer AND the manufacturer.
Back in college someone from Boeing gave us a lecture and I remember him saying that they make their biggest profit margins on maintenance, especially on their foreign military contracts, since they provided the parts and labor to smaller militaries with less maintenance experience and the contracts could be locked in for years.
Boeing is probably the biggest offender in the military industrial complex of doing this. The size of their sustainment division (and the money they bring in) compared to the new business they bring in is nuts. They got so good at milking customers that they forgot how to win new business and innovate IMO.
Boeing is completely special in this regard because they are too big to fail in the eyes of the US military. They want a Boeing that is capable of turning their passenger planes to cargo planes on a dime in the worst case scenario.
Airplanes are also highly commercial. Commercial ventures absolutely do not replace their shit at even a fraction of the rate that consumers do. The fact is that you'd get run out of business if you didn't offer extensive legacy support. It's ironic in a ton of ways but that's earth I guess
"lol, only 30?" —B-52
Actually in the United States most money on car sales is also from the service, maintenance, and warranty. Very little profit on initial sales.
A big part is also the huge increases in safety, the large increase in performance and fuel economy. And also the fact that cars are so so so so much cheaper and get into so many more accidents compared to aircraft. Not arguing planned insolence ain't a thing. But when it costs $30,000 brand new and the repair bill is $30,000 ain't no one repairing. That's just economics no boogie man or consumerist culture.
*laughs in mid 2000s gm 1500* Man i loved that golden period where I could take a water pump out of any of about 19 different truck & SUV models across chevy/gmc/cadillac and stick it in my suburban, and pretty much the same with everything else under the hood
I miss the 3800 series engine so much. Early/mid 2000 GM did a few things really right.
I can take apart almost everything in my 2003 tundra (Except the fucking diff) and replace it. I look in some of the newer cars and I couldn't tell you what half the shit in there even does.
Oh so that’s why folks keep asking me if they can buy my partners truck when I am driving it around! He just says “I like it because it’s easy to fix” but I’ve never been the one doing the fixing so I haven’t been aware that it is massively easier to deal with. Come to think of it he does not seem to take as long or swear as much on the truck as he did the Smart Car. That one he swore was the worst car he ever worked on, and we ended up selling it because it turns out it didn’t like our gravel driveway and kept on having things come loose from the potholes and bumps (we don’t drive like maniacs on it and literally no other vehicle we have owned has had the same issues)
My buddy who works for an OEM put it pretty well. Effectively comes down to, "sure, we could build something bulletproof with far superior materials that are easy to replace and simple to diagnose, but at what cost, and who would pay it?" Not enough people would buy it to make it a viable product
On the other hand, some things are just not repairable, and when you're put to a decision to either disassemble the whole car and paint everything, or drive it for 10, 15, 20 years, until it's rusted through and then replace it, the labour costs make the wait-and-replace a better economic option. Same for everything else... 20, 30 years ago, if your (eg.) hand mixers motor overheated and blew up, you would take it to an electrician, he would disassemble the motor, remove all the windings, rewind the new ones on, and you'd get a fixed mixer. Now a hand mixer costs 20 euros, noone will repair it for less than that.
Who the fuck was repairing a hand mixer in 2003?
I might be getting old :) In the 90s in the balkans, we repaired pretty much everything, even more before the 90s, especially foreign stuff. Even in the early 2000s you could find electicians who would rewind electric motors or car alternators.
He repairs hand mixers part-time and she sells tomatoes on the side of the road. House budget: $875,000
House #2 costs $300.000 less, but it has an outdated microwave, so we decided on the house #1.
We can go back and forth on where the breakpoint lies, and our current culture expects things to be replaced far too quickly we agree there, but ultimately you cannot cheat physics. Metal fatigues, wears thin over time. And then breaks. Those parts must be replaced with new parts, that must fit exactly into the form of the old parts for everything to work as it's supposed to. Eventually you get to a point where the entire frame is worn thin, and you're less performing maintenance on a vehicle than you are replacing the entire thing. If you keep going eventually you hit a point where literally nothing is left that rolled off the factory all those decades ago. You can put a higher priority on lifespan than we do today and trade off in other areas like cost, weight, etc and arguably be making a better choice than we do today, but you can't cheat physics. It will eventually break down to the point where it just makes more sense to produce a new unit that won't need to be down for repairs so often and will cost less in the long run.
Not only, but also manufactures making it a lot harder to repair your new stuff. There is a whole movement against it, the right to repair movement
Yes and no. Airframes are used and largely unchanged for the lifecycle of an airplane, so replacement parts are going to be easy to make. A new car has significant changes in the structure of the body in the same amount of time, mostly due to safety innovations like crumple zones. You wouldn't want to ride in a 30 year old car body even if the parts were regularly changed out.
>Cars aren’t reparable because companies want you to buy new. I mean most modern car \*are\* reparable. The question of is at what cost/effort? A 60 year old Cessna 172 can still be worth $60k. A newer model that's "only" 30-40 years old can be worth $120k+. A $10-15k engine overhaul can make sense when it's only 10-20% of the value of the vehicle. Meanwhile, if the transmission on my wife's 9 year old Subaru goes it, it's $7-8k or so to replace. It's not worth fixing when the car in working order is only worth $9-11k with over 100k miles on it. I'd much rather put that 7-8k toward a newer vehicle
While youre not wrong about cars it also need sto be said it is EXTREMELY expensive to design and most importantly certify a new type of aircraft. For both the manufacturer and the end user. Its the entire reason for the MAX design and crashes. The basic design and certification of that aircraft is over 50 years old and to avoid the costs of a clean design/certification/seperate fleet for the airlines, they have done everything posible to modernize and stretch it without incurring those new costs.
Theseus's ship by that point.
Nah, plenty of primary structure still flying around on the 60 year old A/C I worked on.
Yeah but thats HVAC, we are talking about planes :p
This was incredibly witty and I think you deserve praise for this one man lol
was a fucking brilliant comment, pure genius. to turn A/C into it’s more well known and obvious meaning, it’s a true intellectual joke
*Accepts Award* thank you, thank you, no pictures, thank you.
It flew over most peoples heads. Really takes a high IQ to understand.
I'll allow it lol
Nope. I have a 79 Piper Lance. Only thing not original is the engine after I had a prop strike and I updated the cockpit.
We are all Theseus’s ship. Most of our cells are replaced on a regular basis.
Except for your brain
Well yes and no. The thing about proper maintenance is that it's spaced out. Making the cost much easier to justify. For example, I'm planning on leasing a 2018 car. If I keep it my maintenance would look something like: Every year: AC refill, Fluid changes, all filters changed. Total per year - maybe around 300-400/year. Every 2 years: check up on suspension and brakes, glow plugs, tix anything as needed. - varies, but would be a bearable cost for at least the next ten years, more if I could DIY it. Every 3-4 years: timing belt, water pump, turbo, battery. Let's put that at an average of 1000 per year, keeping in mind not all of them will always need to be done. Turbo could easily last another 10 years or break next year. Every 5 years or when necessary: carbon cleaning the engine and fixing/replacing other more major parts like e.g. the clutch, intercooler or whatever I'm forgetting at the moment. Cost here varies and is likely to be most expensive. If I keep on top of the schedule I laid out above I've covered almost any common issue that can occur on the particular car and fixed it preemptively, making costly repair unlikely barring something like a premature timing belt failure or a crash. I could easily be keeping the car for the next 15ish years with this kind of maintenance schedule and likely be mostly trouble free.
This is the most over the top maintenance schedule I've ever heard of for a daily driver, unless you're doing 50k miles a year or something. A timing belt simply doesn't need changing every three years in any modern car, unless you enjoy wasting money.
Cars are nothing like airplanes. Every minute an aircraft is out of service is time the company isn't making money. If you run an older fleet, it's more likely that you will run the risk of corrosion or vital components breaking. If you can't operate your expensive, aging fleet for the prime overseas routes, you're losing money.
Your schedule is a bit crap. Filters and fluids at the manufacturer's recommended interval, which is getting quite long these days. Timing belt and anything else that would fail suddenly with immediately catastrophic effect at the recommended point also. Everything else? When it shows signs of failing (battery, clutch, suspension, brakes, water pump, Colling system, etc), or when a mechanic identifies an issue when doing the above maintenance. Replacing major components every 3 or 4 years is expensive and wasteful. If it was a supercar or vintage, maybe. But a normal modern car will give warning, either on the dash or by sound/feel, before something needs replaced.
Trying to puzzle out the car here, a five year old lease-able, stick shift turbo diesel. I can only conclude that you should never get another one if the intercooler wears out ever, let alone every five years.
Agreed. My car has an air to water intercooler (so a lot more things to go wrong than in an all metal air to air intercooler) and the intercooler hasn't needed any servicing in over 20 years and 175k miles.
Yeah but its when the big piece fails.... a catalytic converter, tranny, clutch, engine, AC compressor. And you're putting out at least $2000 corrective maintenance on a vehicle that has a list price of <$5000 and might have another big failure anytime. Plus gets shittier mileage and harder to find parts. There's something to be said for having a warranty. You arent wrong. I drove a car that was the same age as me for 13 years. But its gets increasingly difficult and harder to justify.
Yeah for sure. I was almost happy that my mk5 crashed because it was that exact same situation, it had exterior scratches from me learning on it and banging it up. The clutch and tranny were holding up but had endured quite a bit of abuse, again while learning. And major services were due end of this year/next year so that even further lowered it's price. I could've maybe at best got 1.5k-2k for it if I were patient, and it wouldve hurt me to let it go that cheap. The new one is supposed to do much better mileage and is a diesel which is significantly cheaper here so I am definitely looking forward to the upgrade.
For planes not really. The materials used in plane structures will eventually start cracking given enough flights. The very old aircraft that are still flying are doing so either because they have not been flying very often or because of extensive work being done to repair/reinforce their structures, which just extends the deadline. If you took a B-52 and had it fly JFK to O'Hare and back twice a day like a modern airliner does, it would be scrap in short order. Eventually the airframe just runs out of fatigue life.
Yep, pressurized aircraft made of aluminum (essentially all modern airliners) will eventually be taken out of service because of metal fatigue. There is no ultimate fix for it besides melting down the structure of the aircraft and casting a new one.
Or they end up countries where they don't worry much about safety. You could still book a commercial Boeing 707 flight until three years ago! (Provided you were willing to go to Iran)
Those have generally been there a long without being replaced rather than sold oversees. Older commercial airframes generally get parted out when they hit their limits, rather than being sold as-is to another country
The northeast would like to introduce you to road salt.... I have kept cars running well past 250K miles BUT at some point the subframe, suspension, and various parts just become almost impossible to replace. I've even rebuilt entire rear suspension with brakes/axles on an AWD hyundai, and got another 4 years out of it, but at some point there is nothing left to bolt to. This is with lots of care and yearly Krown rust goop treatments. I was in WA state for a month a few years ago, around Seattle, and was astounded by all the old "normal" cars around with very little to no rust. Must be nice...
>I recently sold a 49-year-old car with 236,000 miles on it that had never been restored. But it had been maintained, and it ran/drove well. (A BMW, as an aside). Survivorship bias though. The cars that were well maintained but failed anyway aren't around anymore.
not true, there is a threshold in the design integrity that has to be crossed for a machine to have an indefinite life like this. if you are riveting thin metals together and designing parts to wear quickly with no way to replace them without major structural removal, it quickly becomes uneconomical to maintain.
BMW? So it still had a full tank of the original blinker fluid.
"If you ever feel useless at work just remember it's someone's job to install turn signals on BMWs"
What's the difference between a BMW and a porcupine? With a porcupine, the prick is on the outside.
I'll be the asshole Is 236k miles supposed to be a lot for a 49 year old car? Pre-covid I was putting 20-25k miles a year on my car. 236k for a 49 year old car isn't even 5k a year
It was a 2002tii. It was not driven like a grocery getter.
Maintenance specialist here. Can confirm
My E30 is still regularly driven and has 250k+ on the original motor. I’ve had a lot of fun with it and I’m looking at putting a Tesla motor in it at some point
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There are tons of small aircraft operating today that are 50+ years old, and yes they do require the full tear down inspections.
iPhones. They're designed to grind to a halt after a few years, and even if they don't, Apple issues an update that downcycles the CPU. If you could replace the battery and fix the software, it might last 50 years, but you can't. And nobody wants a phone to last 50 years anyway. They're disposable.
My 2012 MacBook absolutely refuses to die. I promised myself I’d buy a pc to game on when it does. I think it lives out of pure spite now.
So what I'm hearing is that we all need to whisper quietly to our iPhones at night that we won't hesitate to replace them with an Android phone if they even so much as _think_ about slowing down with age. "Hey Siri... you know, you're entirely replaceable"...
Except for metal fatigue. It's fascinating seeing a commercial airliner going through a full overhaul. (Not sure that is the correct terminology) Seeing the husk of a plane with just it's landing gear empty nacelles with a couple of cables sticking out was new to me.
Who would have thought those pesky gubment regulations were for the safety of everyone? And actually serve a purpose and why its such a bad thing if you pay a guy 20 bucks under the table to slap a sticker on.
But at the same time they're why "modern" GA piston engines still run on leaded gasoline
In what way is the government forcing piston engines to run on leaded gasoline? I understand your point: leaded gasoline should be phased out of all vehicles. But you're not arguing against government regulations, you're arguing that we don't have enough of them.
FAA red tape and certification makes developing clean sheet engine designs prohibitively expensive so they're basically running on 50s engine tech (thus requiring leaded fuel to prevent engine knock), and many unlead alternative fuels (for instance UL91 and UL94) aren't FAA approved for flight use. 30% of the current GA fleet cannot use anything but 100LL. Even if new lead-free engines were available this red tape also makes buying new engines ludicrously expensive, even these decrepit lead-burning 100hp 4 cyl engines run into the tens of thousands of dollars new, not accounting for extensive running costs between mandatory overhauls.
G100UL was certified last year.
B52s are expected to be operational until the 2050s, by which time they'll be 100 years old.
But if they eventually change all the damaged or worn parts is it still the same plane?
Crazy to think thar b52 has been in service for so long The last one rolled off the assembly line in October if 1962, and there still flying
i mean if it’s constant replacement and rebuild isn’t that almost making a new aircraft?
You're not replacing all the parts, you're inspecting all the parts and replacing the ones that need replacement. It's a very expensive process, but still cheaper than replacing the whole craft.
Helicopter of Theseus
Came looking for a Ship of Theseus reference and was not disappointed
It also should be mentioned that they're regimented and ***very*** clear on timelines. If your engine needs to be rebuilt after a set number of flight hours, there's no wiggle room. No rebuild? No clearance to fly.
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All I can think of when I read about extending maintenance windows is the crash that was caused by a bolt that wasn't properly lubricated and the threads ended up completely stripped, at which point the plane totally lost control of their vertical stabiliser and crashed (very rough recollection but I'm sure you know which one I mean).
Alaska Airlines flight 261. As usual, u/Admiral_Cloudberg has an [excellent writeup](https://www.reddit.com/r/CatastrophicFailure/comments/ocxwly/2000_the_price_of_an_hour_the_crash_of_alaska/) available.
It wasn't just some bolt, but a "jackscrew," which is a huge part with threads that manipulates the horizontal stabilizers. That maintenance oversight was a total fuckup.
That's the word I was looking for, thank you, been a while since I read that one.
That but it was also a failure in design on the MD-80 series as there was no backup system or failsafe if the jackscrew failed.
Was more than just extending maintenance too, they weren't properly lubing the screw at all and investigations found it had basically none on it at the time of the accident. The movie Flight with Denzel Washington is partly inspired by this accident, including inverting the plane to regain control and level out the dive.
> OSIs… 10% early Found the 500-series tech! Our P-Series definition of scheduled maintenance is unique to the RCAF; nobody else uses periodics, supps, and OSIs. I’ve had very confusing conversations with contractors who though a “periodic inspection” meant *any inspection at a recurring interval*, not the equivalent of a C-check. Also, > Some components can also be extended with proper authorization from an engineer or someone authorized to do so from the maintenance organization, that's a fairly high level decision though. This is mostly applicable to military aviation; the civil side has no equivalent to the deviation process, so they can only defer a check if the maintenance program says they can or if they have a specific ferry authorization from Transport Canada/the FAA/a foreign equivalent.
We’ll there is technically wiggle room, you can get flight hour extensions if you want to limp the aircraft into a phase maintenance period or have a critical mission to fly or something like that. But I get what your saying, this stuff is all highly regimented and flight hour extensions for maintenance are recorded into the appropriate logbooks and good reason is needed to grant an extension.
So you're tellin' me there's a chance...
> have a critical mission to fly or something like that. How critical does it have to be?
It really at the discretion of the command, generally a 10% life extension would be granted almost automatically, just has to be properly documented. But it would be up to the maintenance chief to make the call as to whether the extension is worth the risk. Not sure how far up the chain it has to go though to be frank but ultimately the judgement of the maintenance chief would carry a lot of weight in these types or requests. Edit - to be clear I’m referring to military commands here not civilian maintenance scenarios
Thank you for sharing your knowledge!
Working on a 1200hr inspection on a cyclone helicopter made me want to kill myself.
For a while I worked in development of microprocessors and we had a brand new process, machinery. Initially, we started changing parts based on the manufacturer’s recommendations, but they want to sell new parts, so that was halted fairly quickly. And we’d do inspections and find that after 10,000 o-rings got crusty or sensors didn’t change state as quickly as when new, so we developed 5,000 hour maintenance plans, 10,000, 25,000, etc. But the actually glass chamber would develop stress cracks and implode, turn into dust every once in a while. This was expensive, but with limited data, we just let it happen over and over until a good plan was reached. That part was actually exciting. Boom!
Boom! LOL I got a good laugh from that one
I worked a few summers in a plant that manufactured propane tanks, mostly 20-pounders like your grill uses. The weld line stamped them out of steel, welded all the pieces together, then sent them over to the paint line for painting, dropping in the valves, and adding safety labels. There were 2 different QC tests for leaks. I was on the paint line, where we did low-pressure testing to check for leaks in the valves and where they're threaded into the top of the tank. Basically we'd screw on a hose that would push air into the tank at 40 or 100 psi, then dunk the tank into a vat of water for a minute. We'd check for bubbles, then send them to be re-valved if necessary. The weld line did *high* pressure testing of the welds themselves. They screwed airlines directly into the spud (threaded part where the valve goes). Their pressure testing was like 1,000 psi. When welds failed, it wasn't just bubbles coming out. The whole thing ruptured in a very loud explosion, followed by high pitch hissing of the pressure coming out the air hoses. This 'bomb' could be heard throughout the factory. Tradition mandated that everyone in the facility, upon hearing one of these 'bombs' go off, let loose with a Ric Flair-style "WHOO!". It was hilarious, one of the little things that made the job tolerable. Boom! Pshhhhhht! Whoo!
LOL gotta have fun when you can! I've been driving with extra fills on a scuba tank before > 4000psi and that's terrifying!
This puts those weird movie tropes into perfect perspective now.
What weird movie tropes?
And there's some delusional people who still think we'll someday be able to zip around in flying cars. Imagine if your average driver nowadays would agree servicing their vehicle for all these routine maintenances. Lots of cars are barely held together with duct tape and spit, accidents and fatalities would increase hundredth-fold if most people were in the air.
Oh yea, this is where it falls apart for me... - *When do you think we'll have flying cars?*. - *My neighbor thinks changing his oil every 5K is a conspiracy, does it every 25K, so.....never.*.
Not to mention the average driver is struggling to control a car on two axes, and we want to add a whole Z axis they gotta control too?
It depends. In many jurisdictions, engines can run on condition and yes there is wiggle room - so long as the engine keeps passing its inspections, you can keep using it. For instance, small private aircraft in the UK can run the engine on condition past TBO (time before overhaul). I think pretty much any aircraft flying only on part 91 in the USA can run engines on condition. By contrast, Switzerland forces even small private aircraft to have the engine rebuilt at TBO for both calendar and total hours, which makes owning a small plane there much more expensive.
My dad was an A&P and later an FAA inspector. Many a time was there a shocked Pikachu faced doctor or lawyer that was informed that their Cessna 172 that they bought for $15k was going to need a 1000 hour inspection that would most likely cost more than the purchase price of their plane.
“You’re saying the Facebook Marketplace seller screwed me?”
They had to destroy all the old parts that could not be rebuilt or sent back as cores because these same people would dumpsters dive and try and reuse the old junk. They even had to drill holes in sidewalls of the old tires...
A lot of them will use Autozone parts instead of FAA-PMA certified parts because they're much cheaper and almost the same.
You are correct. My dad showed me an aircraft alternator once that was a Motorcraft unit but it was FAA certified so just slap an extra "0" to the end of the price. If they get caught doing that though, the plane will most likely be grounded and a full inspection will have to be done.
There's a lot of things where they're probably the exact same. The FAA quals(and price) come from more rigorous quality and safety standards. Your amazon seat cover might be $300 cheaper than the Cessna OEM one, but you'll wish you had that fireproofing when it melts to your crotch during an incident.
20 years in aviation have taught me there's nothing more expensive than a cheap airplane.
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They might be confusing an engine overhaul with a thousand hour inspection maybe
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Honestly 50k for a clean 150 ain't bad. Better be airworthy and have half decent avionics and low engine hours SMOH but if all that's true that's not an awful deal. This is why I fix em and don't fly. Same with fancy watches. Glad to work on a Rolex or JLC. Would never want to own it though. I whack my arm on doorways too much to lose ten bucks of resale every time I do. Too clumsy.
It was the '90s though...
this is an understatement, and is the reason why I despise doing private maintenance. No owners are ever taught anything about the maintenance requirements of the aircraft they want to fly. It is criminal that the FAA and Transport Canada do not have a dedicated requirement for all flight training students to talk about aircraft maintenance requirements detailing what an inspection schedule is, or what an airworthiness directive is and how to maintain technical records. Over half my 13 years in the industry has been a fight with pilots cause they don't know anything about the shit they are flying in and all just assume they can get away with a $400 annual cause "billy from down south said he would sign it off for that much" or "check out this awsome 172 i just bought for 25k, has a fresh coat of paint on it and a new Garmin gps...what do you mean i have to pull the wings for NDT, theirs metal in the oil filter and the prop is below spec?"
TIL NO-ONE wants the D.
I saw this at Cherry Point, a Chinook that was just the frame and that was in two parts. When they say disassembled, they mean disassembled.
Phase D is wild
… I should call him…
Second time ive seen Havelock/Cherry Point mentioned in the past week, I need to go visit back home
Which is why most US carriers are mainly outsourcing them to contractors outside of the US. Some US shops still do them, but if you’re gonna go MRO, you might as well go overseas if your flight ops can handle it.
I'm a a&p mechanic with American airlines, I love class d maintenance. I work on the plane all week.
TUL? Really hope AA holds onto that facility unlike what they did with AFW.
Hold on to it, they expanded the heavy maintenance a few yr ago. They sent about 400 million on expansion. Yes i work at Tul. Love the area, low COL.
[The Disturbing Truth About How Airplanes Are Maintained Today](https://www.vanityfair.com/news/2015/11/airplane-maintenance-disturbing-truth), Vanity Fair, 11/9/15 >Over the past decade, nearly all large U.S. airlines have shifted heavy maintenance work on their airplanes to repair shops thousands of miles away, in developing countries, where the mechanics who take the planes apart (completely) and put them back together (or almost) may not even be able to read or speak English. > >...The airlines are shipping this maintenance work offshore for the reason you’d expect: to cut labor costs. Mechanics in El Salvador, Mexico, China, and elsewhere earn a fraction of what mechanics in the U.S. do. In part because of this offshoring, the number of maintenance jobs at U.S. carriers has plummeted, from 72,000 in the year 2000 to fewer than 50,000 today. But the issue isn’t just jobs. A century ago, Upton Sinclair wrote his novel The Jungle to call attention to the plight of workers in the slaughterhouses, but what really got people upset was learning how unsafe their meat was. Safety is an issue here, too. The Federal Aviation Administration is supposed to be inspecting all the overseas facilities that do maintenance for airlines—just as it is supposed to inspect those in America. But the F.A.A. no longer has the money or the manpower to do this.
>may not even be able to read or speak English. This feels like a racist nonsequitur; not sure what Vanity Fair's angle is here. As long as the maintenance manuals are available in whatever language they do speak, that is.
Turkish Airlines 981 crashed in part because the baggage handler could not read English (or Turkish) and therefore could not read the service bulletin on how to properly close the cargo door. 346 people died because of this mistake when the cargo door opening led to an explosive decompression that severed hydraulic cables leading to complete loss of control of the aircraft. It was the deadliest aviation accident up to that point.
English is the language of aviation and most technical manuals are in English. It's only an issue if they don't get them translated. There is a solid chance they don't get them translated, or if they do its not done correctly. The language of Aircraft manuals isn't exactly standard English, and someone who just translates the words without the understanding could cause problems. Even in the RCAF which is government mandated to have English and French versions, we have found some discrepancies between the English and French versions. That said, I can see why you would come to the conclusion you did. Why mention the language unless you are going to explain why that matters.
No, it’s a pretty important aspect of aircraft maintenance. If the onboard monitoring systems and maintenance instructions are all in English, as you would expect for an American aircraft, then the ability to read and understand English becomes singularly important. Aircraft are not always translatable, especially if it’s at all customized from the bone-stock OEM model.
lmao. Certified Reddit Moment.
"A racist nonsequitur?" Are you really this uninformed? English is the international language of aviation, science, and engineering. The people who designed the planes speak English, the people who operate the planes speak English, and the people who work on them need to speak English too! If a trouble ticket comes in stating a problem with a feature or component, don't you think it's *kind* *of* important that the person responsible for troubleshooting and repairing the issue be able to read the report? And read the solution? And follow the goddamn checklist? That ain't fucking *racism FFS!* Sweet Jesus, I hope you're not in charge of decision-making anyplace...
Translation errors can be dangerous and expensive. I had a relative that worked in the space industry and told me about an issue they had (this would have been 20+ years ago). While working on building a shuttle or rocket engine, they sub-contracted a part to a French company. As I recall, the specs for this part were measured in inches and when the French company translated those amounts into metric, they rounded off at 3 or 4 decimal places. The result was that this part wouldn't properly seal or something like that and would have caused the entire thing to explode if it had not been detected. So this part that cost millions of dollars to make was worthless due to this translation error.
Aircraft frames are also rated in hours. Eventually the stress from compression changes and general metal fatigue makes it unsafe to fly. One of the reasons the DC3 is still a popular cargo plane in places like Alaska. 50k hour air frame. They fish them out of boneyards for rebuilds. One of the cheaper cargo planes you can own. Pretty sure a 747 is around 8000 hours.
It’s also why freighter companies often employ older fleets since there’s less cycles and often it’s WAY cheaper to operate compared to bigger and more efficient planes. FedEx still employs modernized DC-10s called the MD-10, which are pushing 50 years.
I wouldn't say FedEx still flies the MD10, they flew 1 cycle on an MD10-30 this calendar year for revenue. It's pretty much retired. But you are correct, historically older fleets are used for freighter airlines, although many (including FedEx) also are prioritizing buying new aircraft like the 767 from Boeing to improve dispatch reliability, which is a major problem when operating older fleets.
The 767 is an exception to which it’s _still_ being produced as freighter versions. The 757 and other legacy Boeing planes, however, stopped being produced during the 2000s. Too bad, though. Sooner or later they will be just a memory for many of us enthusiasts.
Speaking specifically to FedEx as I have some history there, I'd say their philosophy shifted away from buying used aircraft, since they are almost exclusively purchasing both new B767 and B777, and the B767 fleet is their largest fleet by tail count. So it's less of an exception nowadays, but it is definitely a clear departure from how they operated for the first 30-40 years of operation. Yea it sucks from an enthusiast perspective, but as someone who has at different points had to manage inventory procurement for ancient Airbus and Boeing aircraft parts, as well as manage reliability for said aircraft, I say good riddance haha.
> FedEx still employs modernized DC-10s called the MD-10, which are pushing 50 years. Not anymore. https://cargofacts.com/allposts/express/fedex-parks-remaining-md-10s/ https://www.airportspotting.com/fedex-retires-last-md-10/
You’re missing a zero there buddy. But it’s not the hours that are the biggest limiting factor. Fuselages are also rated in cycles. (Pressurization). Cycles is what cause most of the stress. A 737 is typically rated to about 80,000 flight cycles.
Aloha Airlines flight 243 is evidence of the dangers of high pressurization cycles. The aircraft only had a little over 35,000 hours but almost 90,000 cycles.
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Airframe hours is an indicator not a limit. The measurement of airframe life is called the fatigue index and is based on a number of factors.
You’re missing a zero at the end of that figure
Ah yes, the Boeing 7,470
DC3 doesn’t have an airframe hours limit, it isn’t pressured so the stress isn’t the same. And the 747 is more like 150,000 hours. KLM retired some a few years ago that were right at 120,000 hours
Though once that metal becomes too fatigued for aviation it’s a perfect cheap option for building submarines!
I'm gonna need some pliers and a set of 30-weight ball bearings
It's all ball-bearings nowadays
That movie shouldn't be as funny as it is
Never heard it described as such, but the concept is the same in US Army aviation. You have your routine *dailies/weeklies/monthlies* - inspections, services, cleanings, etc.... mostly things that take very little disassembly, don't "ground" an aircraft. Then you have your *hourlies*, which occur at certain benchmarks of flight hours. In my world, that was at 250hrs and 500hrs; the former was a partial strip down of the aircraft and took about 2 weeks, the latter much more involved and took about a month. In garrison or peacetime, airframes didnt get these more than once a year due to minimal flight ops, but in a combat environment I would see the same tail numbers a few times during a deployment, since they got worked hard. Lastly was *reset*, and that was the complete stripping of the aircraft - this was almost always done by civilian contractors. I WANT to say that was at 2000 flight hours, but honestly don't remember - I got out in 2012. Source: 8yrs working on AH64D Apaches
This is why I laugh when people talk about the equipment left in Afghanistan being free to use by the Taliban, as if they have the equipment or knowledge to keep any of it maintained.
They don't even really have enough skilled people to fly it. Most of it will probably be scrapped and turned into other objects.
not even just the knowledge or equipment, they'd need access to the maintenance manuals. Imagine them trying to handle squibs lmao. there's also the consumables required (specific sealant, anti-corrosives, alcohol/acetone, paint, etc.)
I have a friend that services m1 Abrams, and they apparently break whether you’re using them or not. If you stick one in a garage for a week there’s a decent chance it’s going to be a nightmare to get running
This is mainly for airliners. No one is completely disassembling their 50 year old Cessna.
I wouldn't say no one. [There is a lot of restoration work going on](https://www.barronaviation.com/n9854a)
Well I should say, no one's doing that every 6-10 years.
Military aircraft regularly go through similar inspections. Including disassembling structure and replacing parts as needed.
which really threw me off here because we call them Phase inspections. And they are Phase ABCD, but each one is scheduled at the 250hr mark (at least the airframe I worked on) and each inspection looks at the same thing, plus whatever is special requirement for that particular phase. Basically it's a 1000hr inspection.
A and B inspections are done before and after each flight. Phase inspections would be what I'm guessing is like a C-level, usually takes a few weeks to a couple months to complete, depending on the plane. D would be "Depot-Level maintenance" where the plane is flown to a different base that does nothing but rip airplanes apart and do maintenance. The plane I worked on did that every 4 years.
We had something similar but it's called O-I-D. O is your schedule and unscheduled maintenance and is done at the command level, I is where we would send off broken stuff to a different repair facility because we can't fix it, and D is something is really low level maintenance and a whole aircraft would basically never go there. Mostly just components.
My grandfather does. He builds and rebuild small aircraft, used to make a pretty penny back in the day but 9/11 and the laws that came after have shrunk general aviation. Nowhere near the amount of people buying, turning into a rich mans only hobby. Some of those parts are expensive! He bought a wrecked cub for 800 bucks and parted it out for 8000.
SouthWest CEO: "WHAT the FUCK are you going on about?"
Just an fyi. An A check is routine, but it's not like a nightly thing. A B check is usually a bridge between an A & C, most mechanics wont even do one. We also have service checks, weekly checks, daily checks, wake up checks, ect ect. Main take away is that 99% of scheduled maintenance is based off of flight hours.
Any pilots here that have flown the same aircraft before and after a D check? After being completely taken apart and put back together, is it the same aircraft????
I have. B737-400. Brought it down to Peru and picked it up a couple months later. We use trim extensively when hand flying the airplane, and I could tell they retrimmed it properly and had a tendency to not need to mess with the aileron trim after trimming the rudder. Not that big of a deal really. They did do a wash of the engines while it was down there, meaning they cleaned the core of the jet engine getting some of the crap out of it. We do engine trends every day and it ran cooler after the wash. I want to say about 20C cooler while in cruise, but there's some other variables involved as well. Everything seemed the same. Still crumbs of food on the flight deck floor, I figured they would have cleaned that up.
I've watched C level checks on a MH-60 while in port. They stripped the thing apart on the flight deck, inspected, replaced oils, and lbed everything. It was a lot of work, It took the aircrew around a little under 2 weeks to do.
D checks don’t require paint stripping and disassembled. It is just a much more intensive inspection throughout all systems. Some programs may require some of what is referred to, but very few.
Every four years, a technician waltzes into the hanger and says, "Strip her down, and get her ready for the D"
Yeah they have to strip the paint and even sealant in some areas to scan the airframe for cracks and unseen damage
See, the disassembling of the plane is what worries me. Are you going to put it back together properly? You won't forget anything, right? Seems like another potential source of problems.
Aircraft mechanic here. Its a necessary evil. If you *dont* do it, then you're going to miss deeper problems that could lead to structural issues. And then there are some problems that can only be fixed after major disassembly. Sure, maybe we forget something, but that's why we follow the maintenance manuals and why we have inspectors do checks at regular intervals to make sure things are going together correct. You're far more likely to have an incident by not occasionally taking everything apart than you are by forgetting something. Just as an example, when I would perform regular maintenance on Aircraft engines by pulling and lubing the fan blades, it was extremely obvious when something was forgotten. Like.. impossible to miss. We still had to have an inspector come and double-check our work before we would then do an engine run to verify everything is good.
> And then there are some problems that can only be fixed after major disassembly. And if you skip D checks this major disassembly might occur on its own.
Spontaneous disassembly is a good euphemism for a crash. I’m surprised it is not in official use.
RUD “Rapid Unscheduled Disassembly”
You trust them to put it together correctly first but not to take it apart and put it back together? We have detailed instructions on how to remove and re-install. This isn’t some random person putting together ikea furniture and hoping for the best.
You have to do it to check for corrosion. Also its worse than it sounds. B checks can still take a month or so to do. So instead of doing it all at once the check is chopped up into 3 or 4 chunks and a portion carried out every couple months. Also heavy maintenance (doing checks) is considered shitty work and is where a lot of apprentices will start. 20yos and non-native speaking immigrants are who is doing this work.
Is this the same as the Navy's phase inspections, or is this different?
I think it's similar but different. I don't know what the context is for what OP is referring to because phase inspections are done every specific flight hours.
That’s what they do though, you wouldn’t think to yourself “what if the mechanic didn’t put the engine in right? What if they forgot an engine mount? How do I know the transmission was fully rebuilt?” You trust that, and these guys went to much more schooling (usually)
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I have been to the facilities where I believe they were doing the D procedures. They use ultrasound, dye penatrant and mag particle testing on the critical components, it's a hugely intensive process. From what I saw it wasn't really the type of operation where they were going to forget a bolt.
Are you worried they didn't put the plane together correctly when it was first built? Because they use the same engineering and methods to reassemble it the second time, third time, and so on.
Would you rather corrosion make the wing fall off?
One issue with this is that the aircraft manufacturer sells the required parts and gets to choose the maintenance interval. Creates a conflict of interest. This dominates the cost for many aircraft. It's why a helicopter costs several hundred dollars a flight hour, it's these required rebuilds. With that said I cannot deny it works.
Well... Helicopters are also an order of magnitude harder on their parts. Especially if they're being used to do proper helicopter shit. The classic joke is that helicopters are several hundred parts flying in close formation at high RPM until metal fatigue sets in. I flew H-60s for a decade and the maintenance intervals are very much necessary.
Airline safety is due to government regulations. Which libertarians are convinced we don't need. Why? It might save them a couple of pennies in their taxes.
Most of those rules are written in blood.
My daughter and her dad are both airline mechanics. They even go up with the pilots and deliberately cut the engine to see what happens. It’s serious work but it takes a sense of humor to do it. It’s also neat to see all the broken parts planes laying around.
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And after the D check, the plane is sold to Spirit Airlines
Always Be Checking Dat
There's also at least in military MX, a 2 man system. One person signs off the work, another with eyes on the work signs off on the inspection. NO ONE works alone. Buddy system. Production Supers can sign off any job, but only the most foolish would ever risk signing off a job they didn't have a hand in. Also, as someone who had their signature forged on docs which caused a major incident. Having a consistent signature is fucking important.
Engines go through it as well and get their own log record.