Is it possible that meteor could strike a commercial airliner?

Question

Is it possible? Are there some such accidents in human history? Is there any rules or systems design to protect airplanes?

Answer 1

Yes, it is possible, however unlikely!

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The final report into the downing of MH17 investigated the possibility that the aeroplane was hit by "meteor or space debris"

In section 3.5 a number of scenarios are analysed that relate to the possible source or sources of the object that perforated the aeroplane. These include meteor and space debris.

It was concluded that

The chance of a meteor striking an aeroplane was calculated as being one event in 59,000 to 77,000 years. This value was obtained from the University of Pittsburgh's Department of Geology and Planetary Science and was originally part of the NTSB's investigation into the 1996 accident to TWA flight 800 (see NTSB Report AAR-00/03, dated 23 August 2000)

Answer 2

A meteorite could hit an airplane, sure. There's no known cases of it happening because meteorites which survive atmospheric entry are very rare, and airplanes are pretty small so the likelihood of it happening is extremely low.

Answer 3

When I served at a military airport in Hungary I read a written report of a MIG-21, supposedly hit by meteor or space debris, crashing the cabin canopy. It was flying with afterburner at high altitude and the pilot's hand was on the throttle lever waiting for instructions. This is why he could manage to slow down and survive. Not an airliner though.

Answer 4

OK, I've been asked to create a "guesswork" answer.

Assumptions.

• 75% of flights are made during daylight hours.
• 75% of meteors occur at night for any given location and those meteorites are equally likely over half the worlds surface (probably about 25% overestimate).
• Aircraft distribution is uniform across the Earths surface (this will make my esimate incorrect by orders of magnitude since they are not, they are far more densely packed over the US, Europe and SE Asia)
• Number of aircraft in the air during the time when the 75% of meteors occur, 2,500.
• Average speed of meteorites, 80,000 mph.
• Average surface area of aircraft, 300 m².
• If a meteor hasn't burnt out by 7 miles, it's not going to (it's a meteorite).
• 350 meteorites per day.

Ignoring the height for now.

Total surface area of aircraft flying when the 75% of meteors fall. 750,000m².

% of Earth surface where the 75% fall covered with aircraft. 0.000003%.

Chance of any meteorite hitting the target surface area (an aircraft). 0.00105%.

Now factoring in height.

• Depth of atmosphere where aircraft are found. 7 miles.

• An aircraft presents a target 150 feet high - big overestimate to account for the time the nose of the aircraft to the tail passes through the track of the meteorite.

• Ignoring that the meteorite will slow down as it passes through the atmosphere.

Assuming a meteorite will pass where the aircraft will be, it spends 0.0036% of the time it falls at the height of the aircraft.

Multipyling the chance of it hitting the area described by the aircraft by the chance of it being at the same height in that area - 0.000000378% or about 4e-7.

Many people struggle to understand numbers that small. To put it into perspective, the accepted chance of you being struck by lightning in your lifetime is 8e-5, or about 200 times as likely as an aircraft being hit by a meteorite.

This is so tiny that any one of my assumptions being wrong will make the number meaningless.

Safe to say, possible, but so unlikely as to be not even worth considering.

Answer 5

Possible, but unlikely. There are no documented instances of a meteorite striking an airplane.

Most of the meteoroids that become meteors are of the size of a grain of sand, and will burn up by the time they reach the cruising altitude of the commercial airliner.

A hundred or so meteors of the size required for impact at high altitudes strike earth every hour. At the terminal velocity of the meteors, the aircraft is practically stationary and the probability of a meteor striking an aircraft is simply the ratio of the total area of aircraft in air to the total surface area of earth.

Around 4000 aircraft are in skies at any given time- each with a projected area of ~300 $m^{2}$ (if we are being generous). This means that the probability of an aircraft getting hit by a meteor is ~$2 \times 10^{-9}$ at any point of time.

Assuming that each aircraft makes a 8 hour flight (again, being generous), the probability of that getting hit by a meteor is ~$10^{-6}$.

So, basically the probability of an aircraft getting hit by a meteor is pretty small; Again, if we continue to operate aircraft at the rate we do, one of them will certainly get hit by a meteor.

Answer 6

This is, sadly, a highly topical question. There have been more than a few aircraft downings where a meteor impact has at least been considered so I think it is worth exploring.

Acknowledgment: In the following calculations have gratefully borrowed figures from various contributors above.

First, let's consider the question about traffic patterns:

• Meteors mainly come from the direction Earth is travelling through space as it orbits the sun (effectively, the Earth "runs them down").
• Meteors are in orbit around the sun before they hit Earth. So they are just as likely to come from inside the Earth's orbit (on the way out from the Sun) as from outside the Earth's orbit.
• This means they mostly occur between midnight and noon the next day. From noon to midnight, you're on the "rear end" of the Earth.
• I'm assuming traffic density between midnight and noon is roughly the same as between noon and midnight. This cancels out any effect of diurnal variation in traffic patterns. If you disagree with this point, divide the answer by two or three.

Second, I am going to integrate over a 24hr period to cancel out the variation in aircraft density as the "front" of the Earth moves round the planet (there are going to be more targets when Europe, North America and SE Asia are at the front than when it's dawn over the central Pacific Ocean).

Third, the aircraft speed is irrelevant. If a beetle is on a dartboard and you randomly throw a dart, it doesn't matter if the beetle stays still or runs about.

Now to the sums: To be clear, I'm trying to work out the probability of any meteor hitting any aircraft in a 24 hour period. This is simply the area of the target divided by the total area presented by the Earth to the oncoming meteor.

So: 10,000 planes in the air divided by 2 (only the leading half of the Earth is in target) $\times$ 300$m^2$ per plane divided by $\pi r^2$ for $r=6371km$ gives $1.2 \times 10^{-8}$. So one in a hundred million, roughly.

Now, how many meteors that could down a plane, hit the Earth per day? Planes are pretty fragile - I'm going to guess that a 0.2m bolide (bowling ball?) if it hit the plane anywhere, would definitely do it. One reference above says there are about 2000 of these per year. So 5 per day.

That gives a final probability that any plane is downed by any meteor in any 24 hour period of $6 \times 10^{-8}$.

So the rate is about once every 40,000 years, or so. Yeah... probably not worth bothering about.

Answer 7

It could happen. This lucky skydiver was only meters from a falling space rock, and got it on tape.

Had he been an airplane (or a few meters longer) he would have been hit!

Answer 8

I see that someone else did the math on the probability already, but I wanted to give some math with dimensions and numbers that might be more accurate, as well as give a comparison to other causes of plane crashes.

At any point in time, there are about 10,000 commercial aircraft in the air, according to flight radar's metrics (although I'm not too sure how accurate those are). Assuming an average length of 50 meters, and a wingspan of 50 meters, and a hull and wing width of 8 meters, that's 800 m² per flying aircraft, and 8,000,000 m² for all planes combined, or about 8 km².

In a comment, someone pointed out that aircraft dimensions are actually closer to 200 m². The reason I chose math of 800 m² is because a direct impact is not the only way a meteor could affect an airborne craft. A sufficiently big meteor leaves behind a heat trail and a smoke trail. The heat trail causes local airflows to change, which could cause turbulence onboard passing aircraft. The smoke trail could theoretically damage the engines similar to how volcanic ash does, given that they're both ash and dust. If a layman is on an airplane affected by one of these incidents, it's understandable that they view this as "being hit by a meteor".

How big is 8 km²? Well, that is comparable to the size of Greenbelt park in Staten Island, and about 2/3 the size of the Royal Borough of Kensington and Chelsea in London. I've tried finding reports of meteorites being found in that area, and while it is not impossible that one has landed there without anyone noticing, it is a very rare event. In fact, while there hasn't yet been a report of a plane crashing by a meteorite, a passenger killing both the captain and the copilot has been reported at least twice as the reason of a crash. I would personally be more worried about a mid-air impact of another plane, given that has happened enough by now to be featured multiple times on Mayday! (Air Crash Investigation).

If you only count direct impacts as actually hitting your aircraft, then assuming an average surface of 200 m² for a plane, and meteors only coming directly from above (since they can also come from the front, the sides or the back), there is a total surface size of about 2 km² when all aircraft are counted. This is a little smaller than the City of London (not the entirety of London, but the original inner city), or just over half the size of Central Park in New York.