What would a Boeing 747 look like if it were left in a hangar for 5,000 years. Could it still be flown?

Question

Assume a passenger aircraft were left undercover for a very long period, perhaps thousands of years, in a damp, arboreal environment. How much of it would survive? Which parts would remain intact, and which parts would decay? What would it take to get it airborne again?

How long could it reasonably survive for, and still be recognisably an aircraft?

Edit

Assuming that it couldn't be flown, how long could an airframe (i.e. just the metal and glass) last, in less than ideal conditions, without mothballing or deliberate preservation, such that an ordinary modern day person could look at it and be able to easily recognise it as such? It might be an irredeamable wreck, but it would be recognizably an aircraft.

Futher Edit (context)

For those interested in further context about the question, this is in regard to a fantasy novel I'm constructing called The Weapon Child.

• There's a sub on Reddit Fantasy Authors here
• The chapter in question can be found here

Answer 1

In 5,000 years it would not be recognizable as an aircraft. There are good answers already with respect to the aging of the aircraft proper.

But what of the environment? Rain will damage the aircraft by rot and rust. Ice will cause stress, opening small cracks. The weight of ice and snow can cause structure failure and collapse. High winds can lift the aircraft and pull weakened pieces off, or the jarring of the aircraft falling when the wind gusts subside could collapse things too. A flood every 500 years doesn't sound unreasonable, so now its full of mud and debris. Or parts float, other parts don't, and the airframe is stressed. If the water is flowing, parts can be torn off. You get the idea. Nature is a tough place.

In addition to weathering, generations of trees and other plants would grow through it, tearing it apart. It would be buried by rotting vegetation and leaves. A fire in the area (once in 500 years does not sound unreasonable) would surely burn away or thin the aluminum sheeting. Remember - after a century, the airframe is full of tinder and it likely sits in a forest. Trees will fall on it.

Of course no one would know the plane was there. Otherwise it would have been salvaged long before and utterly destroyed. So the most you're likely to find, if you happen to look in the right place, are lumps of rusted metal buried deep underground in a forest. Or whatever the area looks like 5000 years in the future.

Answer 2

Your time frame is way, way too long.

Aircraft are incredibly complex machines; let's review a few of the failure points.

Fluids:

• Your first failure point is likely to be fuel. OK, technically the batteries would drain out first, but if you have fuel you can get those recharged in most cases. Your limits look to be around 12 months to 2 years (jet fuel is probably less).

• Hydraulic Fluid. This stuff is under intense pressure and in the course of a couple years those seals are going to fail...now you can't steer, or move the landing gear.

• Oil. It goes bad too, but it takes longer, if the oil was perfectly fresh and in a completely closed system it could hypothetically still be good.

All of the fluid systems are going to fail in the first couple of years.

Electrical systems:

• Wiring is sensitive, any parts not covered in plastic are going to cause you problems...rodents sometimes like wire too...odds are over your time frame something will move in for at least a while. If not, contact points will be the first to corrode. Unattended the wiring is likely failing after 20 years (give or take).

• There are a whole lot of systems in a plane, all will fail inside of probably 25 - 30 years. Navigation will be shot (no satellites), air systems for cabin pressure, lights, etc., etc.

Mechanical Systems:

• Over your time frame...nothing survives except perhaps the remnants of a few larger pieces of metal.

• Odds are the hangar falls on top of the jet anyway...

• Moisture is bad, and persistent. It will get through the hangar roof and eventually make it collapse. Even if it somehow doesn't land on your plane it will allow more water to hit the jet...increasing the decay rate.

In short, there is absolutely no way someone is going to find a flyable jet 5000 years later. Even if the thing were vacuum sealed and stored in a dry underground cave in the desert somewhere it would still not be flyable.

Answer 3

When people wish to mothball expensive equipment for possible use later, they perform a specific set of operations intended to remove the most sensitive parts from the environment.

F-4 (Phantom) at Davis Monthan AFB

Aerial view of Davis Monthan AFB

During mothballing, sensitive equipment like engines and electronics are removed, fluids are drained, and less sturdy equipment (e.g. cockpits) are covered.

Airline companies have a similar facility nearby in which they store retired aircraft.

The US Navy has a facility for retired ships at which they perform similar operations.

The US Air Force Museum's display aircraft are similarly stored. Their preservation is such that by restoring the electronics, engines, fluids, and other components would make (most of) those aircraft flight worthy.

I would assume that using these techniques could significantly extend the time that the airframe could be restored to flight worthiness by many decades certainly. However, I doubt if this would extend to centuries.

Even if it did, who would know enough to do the work and where would the parts and supplies come from?

Answer 4

Thanks for the hilarious question. Might I rephrase like: do you know of many buildings or constructions of a couple of centuries old without any kind of maintenance, that is still recognizable? Let alone operational, in case of a machine?

Let's look at some examples. You talk about a hangar. Just consider your house. How much wear and tear do you see after say 5 years of no maintenance? Paint falling off. Corrosion, wood rot, dirt. After some 20 years of no maintenance or cleaning, it might well be overgrown with plants. You want to add two zeros? Nothing might be left all.

Let's look at climate. Here in Northern Europe, everything might be wiped out by the next ice age, think of an ice glacier of thousands of meters high pushing from the north. Ice ages appear roughly every 10,000 years, and the last one ended about 10,000 years ago, so the next one will most probably be within your time frame of 5,000 years.

Then infra structure. A plane is nothing without infrastructure, like runways, communication, trained personel, fuel of a precise composition, and maintenance. Lots of parts have maintenance schedules based on time, like a checkup every month, or six months. Suppose that after some extreme time frame a part may be in perfect condition, e.g. a turbine blade. If it is not checked up regularly according to its maintenance schedule, it cannot be certified for operation. So in case it might "work", it is useless from the point of certification. Who would risk his life just to "try out" if it would fly?

I mentioned runways. I remember having seen an asphalt road literally disappeared after being abandoned for some 20 years.

How about robbers? I would guess that within a few years the plane would miss essential parts due to robbery. The pyramids prove that even a tough cover will not stand robbery.

Nice question anyway.

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Update:

Yesterday, I unpacked my old record player. You know, from before the compact disc we had those vinyl records? Now, my record player was wrapped in plastic when I moved, and stayed wrapped for perhaps 20 years. Was it operational? In principle, yes: motor, plateau, levers, pickup element, wiring, hinges, cables, even my self-built pre-amp worked. Only one part failed: the rubber belt between motor and plateau was, hum, melted, or, transformed. It was broken in pieces, and most pieces were like peanut butter, or tar. A few pieces could be lifted and removed, other pieces had literally be scraped away. I did not manage to get all sticky tar and rubber away.

Ok, I did get the thing to work with an improvised belt, cut from an old bicycle inner tube, a recent one. But this reminded me of the question about the 747. Just cut the requested timeframe of 5,000 years by a factor of 200 and possibly essential rubber parts may detoriate to a point that it is hardly recognizable.

The moral of the story is that you do not want to try such old equipment. I wanted to try the record player because some people here got renewed interest in vinyl records. But why? Records got dust and ticks, and sucked. Compact disc, a huge improvement, sucked too. Digital music on my hard disk, or the cloud, is much better. Same for airplanes. Even now the 747 is considered to be outdated: too much noise and pollution. Let alone after the next couple of generations of aircraft. Even if the old museum stuff could be flown, you do not want that. Really.

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Update may 2021. Middle/end of Corona Covid-19 pandemic.

More than half of all airplanes worldwide have been grounded now for about a year. As the severity of the pandemic decreases, air traffic is started up again. Experts warn for technical problems because of this mothballing which was only a small fraction of 5000 years.

At 9 january 2021, a Boeing 737 from Sriwijaya Air crashed in the Java Sea (Indonesia) 6 minutes after takeoff, killing 62 people. Experts call as probable cause: storage with no flights for 9 months, and taken back into service too fast.

After a period of no flights for 9 months, the plane was inspected, approved, flown from storage in Surabaya to Jakarta on 14 December, and resumed passenger service the next day. After 132 flights, it crashed at 9th of January. See https://www.nytimes.com/2021/01/13/world/asia/indonesian-plane-crash-mothball.html and https://www.telegraph.co.uk/news/2021/01/13/indonesian-airliner-crash-may-linked-plane-grounded-nine-months/

So, even if the plane "looks good" after just 9 months of careful mothballing, it may not be safe to fly. Let alone when it does not look good after being left abandoned in a hangar for five thousand years.

Answer 5

Plastic hoses, insulation, tires (already mentioned), cable sheathes, anything made of plastic would be useless in such a time frame.

I bought a car made in 1960. When I bought it, it was 40 years old, and had literally been driven by a little old lady less than 30,000 miles and kept garaged. Immaculate! I thought it would be a great car. We had failure after failure of plastic parts - brake hoses cracked, door handles snapped off, wires shorted out, vacuum hoses leaked, seat covers tore when someone sat down on them. Finally had to junk it.

Answer 6

The future visitor will find a layer of aluminum-oxide dust, some metallic copper, possibly some recognizable plastic bits... underneath layers of iron oxide or whatever the building was made of, underneath a considerable amount of earth and vegetation.

Careful, high-tech archaeology would reveal the likelihood of a building. The aluminum, and exotic metals in 4 places and tungsten or depleted uranium in one, would hint of being a 4-engine-on-wing airplane.

Flying it would be out of the question.

Answer 7

As others have mentioned the plane would certainly be unflyable - working components, plastics and electronics would certainly degrade over that long (most likely even with preservation).

However to answer the second part of the question more precisely, given a storage location that did not collapse and was reasonably weather tight the plane could certainly still be recognizable. Think of King Tuts furniture which is over 3000 years old. Even if the structure becomes brittle and collapses you would still have wings lying on the ground beside a fuselage.

(For location, I am thinking of an underground airbase if the entrance caved in and left the rest sealed.)

Answer 8

Supplementary answer. I watched a documentary about a few enthusiasts who wanted to salvage a WW2 plane that had ditched in the wilds of Northern Canada during the war. Their (crazy?) plan was to get it airworthy again and then fly it out using the frozen surface of the lake it was next to as a runway.

They almost succeeded. It took several months of maintenance to get the engines running again. Various parts had to be replaced - rubber in particular had perished. Also all the fluids - oil, fuel, hydraulic. Sadly, something caught fire during their take-off run. The pilots got out uninjured, but the fire utterly destroyed the plane.

So after 70 years in Arctic weather, a plane is just about capable of being repaired.

Answer 9

Considering that it has been stored in a dry environment, in a closed place that doesn't collapse in that timeframe, I think that it will still be recognized as a flying object. Think about the antikhythera mechanism, that has been at the bottom of the mediterranean sea for over 2,000 years and after a large and meticulous study, using advanced technologies, scientists have been able to establish not only what it was used for, how it worked, and aprox. date of construction of the artifact, but also detect and design the missing parts (and allowing to make a replica that works).

The Antikythera mechanism is an ancient Greek analog computer and orrery used to predict astronomical positions and eclipses for calendar and astrological purposes decades in advance.

Answer 10

While natural materials like wood and metal might survive 5000 years in a usable state, there is no way any kind of plastic will survive that long. None of the types of plastics produced have thousands of years lifetime (not even hundreds of years) as a product requirement, and even if they had it is not clear that this would be possible to adequately test for.

Answer 11

There's no way it could survive 5000 years. At this time scales the material diffusion becomes significant, and this will (at least) cause electronic systems death, because some conductors will short-circuit. And without electronics, an aircraft is not usable for flights. Also, we may assume that the temperature will not be constant, so the number of stretchings of the aircraft body will cause severe "metal fatigue" and other destruction.

Answer 12

     You state that your 747 will be sitting in the hanger for 5000 years. I'm afraid that this won't work - the hanger won't last for that long. While the plane is made mainly of Aluminum and won't rust apart, the hanger certainly will completely deteriorate long before the 5000 years are up, exposing the plane to the elements.

      Thousands of years of rainwater pounding against the surface, bits of collapsing hanger, hail, strong winds throwing around whatever debris may be in the area, and any other storms that may or may not happen over 5 millennia will be certain to put holes in your plane. As other answers have stated, all plastics and rubber components will be junk. However, any parts made of iron within the plane that normally wouldn't be exposed to moisture can and will rust over the thousands of years of being exposed to moisture. Another thing to consider is the freeze and thaw cycles, which will pry apart any important moving bits, and pretty much wreck the important systems on your plane.

      Essentially, your plane will be an artifact of a long lost era, nothing more than a bit of metal - that, and a home for whatever animals may be living in what was once a gloriously large plane.

Answer 13

I guess the thing is how "fantasy" is your fantasy novel? No reason why a magic field couldn't have sustained it for 5000 years, or some as yet not invented stasis field.

Still, the question makes it sound like you're after realism so maybe that isn't helpful! :-)

Answer 14

Complicated mechanical equipment degrades with startling speed. A car that has been sitting in a garage for as little as six months probably won't start. After five years, the work of a day can get it back on the road (assuming good tools, fresh fluids, fresh fuel, new batteries, available replacement parts). After a fifty years in a field in a wet climate, cars become an unrecognizable pile of rusted metal. (but aluminum is different)

Hangers are usually just a thin metal shell over steel supports. It's unlikely a structure like that would survive a thousand years in a moist climate. I'd expect a normal hangar to be completely erased after a few hundred years in a jungle-like climate.

If you're interested in the process of decay here's a bit about the degradation: (shortening the timeframe to 5 years when things start to become problematic)

• The fuel needs to be flushed (airplane fuel is less subject to the chemical degradation than gasoline, but after this time I'd expect enough water accumulation you'd want a full fuel system flush before trusting your life to this vehicle.)
• Rubber hoses bushings and seals have begun to degrade. After five years the process has started so there are would be minor leaks and failures of rubber components. After a hundred years rubber will basically have turned to dust. (I've had 30 year old rubber crumble in my fingers like ash)
• Batteries have leaked and are unusable. (all batteries have to be removed and new ones acquired, leaked acid must be cleaned up, contacts cleaned and sometimes replaced)
• New tires. Tires in the landing gear will have gone flat and then been crushed by the weight of the plane (this could happen in as little as six months)
• Hydraulic fluid has taken up water and needs to be flushed. Questionable if the systems will still hold pressure after five years.

The good news though is that if the hanger was built to last it could maintain integrity. (Think of Buddhist temples that have lasted thousands of years in the jungle). The plane itself being made of aluminum would be recognizable basically indefinitely. Aluminum oxide creates a very strong protective layer which basically prevents it from rusting away. I'd expect to see a recognizable fuselage and wings of a plane even after a thousand years.

Answer 15

We are of course intrigued by a long-term storage Jumbo Jet, but this the line of thinking would not be much different if it was replaced by, say, a bicycle, over a time frame of about 50 years. It will not be usable too.

Answer 16

Aluminium has no fatigue limit. This means that as the aircraft structure is subjected to many successive loads, no matter how small, it is guaranteed to suffer fatigue and fail.

Assuming it isn't destroyed by chemical corrosion as others have rightly pointed out, you must consider the loads to which the plane is subjected over a period of thousands of years. For example, if the plane is stored deep underground the temperature will be roughly constant but on the surface fluctuating temperatures will cause thermal stress, which over many cycles will start to cause failures. 5000 years makes for about 2 million day-night cycles, which should be enough to break off those parts subject to the highest stresses. Being exposed to the elements—snow, wind, etc.—would add large loads and speed the process considerably.

My best guess is that the wings may break off, the structure supporting the landing gear may fail and the plane collapse to the ground, the airframe may crack up around all windows, etc. I am obviously not an aircraft engineer so I don't know for certain which parts will be most stressed.

Answer 17

Also remember that the windows are plastic. Once the plasticine leaks out, they will become very brittle. Then the flexing of the aircraft frame will crack and, eventually, destroy the windows. The wings, unless supported would eventually droop to the ground. The landing gear is pretty robust but it is bolted onto the frame. I think that those mounting points will go.

I think that, if you are lucky, after 5000 years, you will have a sagging aluminum tube with holes in it, resting on the ground.