All aircraft today have a ceiling altitude that they cannot fly beyond. The most common range is around 35,000~42,000 feet for large, wide-bodied commercial jets. However, my question is: had there been any cases where a commercial jet somehow flew beyond the service altitude and crashed as a result? In other words, are there any occasions where a commercial jet crashed or experienced problems because they went too high (eg, 42,000 feet or higher)?
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asked Jul 13 at 4:19
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18$\begingroup$ The max altitude for most airliners is generally set because the engines are not able to produce enough thrust to go any higher, not because the airplane wouldn't structurally be able to survive at higher altitudes. So you can't just accidentally go higher than the max altitude, since the engines are not physically able to produce enough thrust $\endgroup$– 60levelchangeCommented Jul 13 at 7:16
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20$\begingroup$ Technically, the four de Havilland Comet I crashes in 1954 come close. They flew within their certified altitude range but cabin pressure cycling led to catastrophic failure. $\endgroup$– Peter KämpfCommented Jul 13 at 12:29
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1$\begingroup$ @PeterKämpf Hi, thanks for your answer. I checked it out and found it to be just what I'm looking for. Again, thanks for the information! I suggest you post it as an answer so I can accept it. $\endgroup$– Aircraft Enthusiast 007Commented Jul 13 at 18:08
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15$\begingroup$ I did not downvote but it's reasonable to conclude something thinks it doesn't show research effort, it's unclear, and/or it's unhelpful. It seems to show a lack of understanding of the basics of flight, and it's a little confusing that the word "exploding" appears in the title and isn't clarified in the question itself. Also an answer would be more meaningful to you than to the general user base. So it could be argued this question meets all three criteria for a downvote. Normally I don't like to comment when I downvote because it seems to invite more arguments instead of edits. $\endgroup$– Todd WilcoxCommented Jul 14 at 7:58
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1$\begingroup$ If you'd asked for aircraft rather than aeroplanes, then almost every weather balloon launched explodes after flying too high $\endgroup$– Pete KirkhamCommented Jul 15 at 16:46
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5 Answers
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Airplanes are dynamically pressurized, not sealed. If the plane could be lifted too high, it would not explode (or otherwise fail catastrophically), but the interior cabin pressure would drop. Besides the normal operation of the pressurization system, there are safety valves that would open if the pressurization difference were too great, preventing something like a fuselage failure due to excess pressure.
Above the absolute ceiling an aircraft can generally not maintain altitude, and attempting to do so can cause problems. See coffin corner. I'm not aware of a commercial aircraft crash that was due to loss of control near the ceiling.
One aircrew did attempt to fly a plane "too high" and crashed it. But the altitude certainly didn't cause the crash.
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1$\begingroup$ Hi, thanks for the answer. I read the article on Wikipedia about the crash of Pinnacle Airlines Flight 3701 through the link you provided. This accident is similar to what I'm looking for, but the main stated cause of the accident is not flying too high. $\endgroup$ Commented Jul 13 at 18:41
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2$\begingroup$ @AircraftEnthusiast007 There were a lot of poor decisions made one after another during that flight. But what started the whole accident chain was their choice to climb that high too quickly. This left them unable to maintain airspeed at that altitude and meant that a stall was inevitable if they tried. $\endgroup$– ChrisCommented Jul 15 at 21:02
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$\begingroup$ The coffin corner kills either by stalling you, or supersonic airflow. While it's triggered by going too high it isn't height related per se, it's just the point where your max safe speed and minimum safe speed cross, forcing you to break one of them. Most aircraft will run out of power before reaching the coffin corner. $\endgroup$ Commented Jul 16 at 1:55
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$\begingroup$ That is an incredibly strange story about the Pinnacle Airlines flight!! How bizarre. Thanks for the link $\endgroup$– FattieCommented Jul 16 at 11:32
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$\begingroup$ Would any of the aircraft designs where an excessive angle of attack can disrupt control flow over the control surfaces, in such a fashion as to prevent recovery, be prone to enter that kind of stall at the service ceiling? $\endgroup$– supercatCommented Jul 16 at 15:37
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A plane doesn't simply "explode" on high altitude because the hull and the pressurization systems are built with safety measures.
However, there are safety problems with flying beyond the specified altitudes. The lift is reduced and the engines produce less thrust.
In a wider sense, West Caribbean Airways Flight 708 can serve as an example of a crash due to "flying too high":
In their calculation of the maximum altitude the pilots didn't account for the anti-icing system that draws power from the engines and thus reduces the maximum safe altitude. Because of this mistake, the plane flew beyond the theoretical safe altitude on autopilot and gradually lost speed until it entered a stall, from which the pilots never recovered, partly because they incorrectly assumed that a flame-out of both engines was the cause of the sudden drop.
Of course, in this case the unsafe altitude alone didn't make the plane crash, but there were other contributing factors like less than perfect behaviour of both the auto pilot (should not silently let the plane enter a stall) and the human pilots (failed to recover from the stall). Nonetheless, the cradle of all the trouble lied in the unsafe altitude.
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$\begingroup$ Yes, you are right. Remember that (1) is not a problem in itself, it just slightly reduces thrust and therefore the maximum safe altitude. 31000 feet would have been a perfectly safe altitude with the de-icing system on. However, at 33000 feet there was not enough thrust in combination with the de-icing. $\endgroup$– mastovCommented Jul 14 at 2:22
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$\begingroup$ Yeah, if the captain had not mistaken stalling for engine flameout, the aircraft would've been able to avoid disaster. Also, I reasoned the autopilot on the aircraft was poorly designed as it did not give a clear warning of the impending stall, and didn't even report the condition after the aircraft actually did stalled. The only thing it did was to increase the AOA to 5.8°, which worsened the situation. $\endgroup$ Commented Jul 14 at 4:39
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One of the most well-known failures in aviation history, that of a number of De-Havilland Comets, was because of the pressurized cabin combined with metal fatigue. So we could say that for its design it was flying too high. (Although it was not known at the time so it did not exceed any officially assigned maximum value.)
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1$\begingroup$ You could also describe some other loss of pressurisation events as 'exploded flying too high' en.wikipedia.org/wiki/Aloha_Airlines_Flight_243 though as per the comet they were not flying above design height, but suffering an issue that rendered the design assumptions invalid. $\endgroup$ Commented Jul 14 at 12:01
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There was a twin jet commuter plane that crashed because the pilots flew it up to 41,000 feet while mismanaging their autopilot, their AoA, and their engine power settings. This led to a both-engines flameout in which they stalled the wing and from which they were unable to airstart the engines because of mismanagement of their descent speed. Both were killed in the resulting crash.
answered Jul 13 at 20:30
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2$\begingroup$ Hi there, thanks for your answer, but can you include the flight number and some links to other resources? Also, I'm wondering if you're talking about Pinnacle Airlines Flight 3701, which the first answer already mentioned. So, are you talking about that case? $\endgroup$ Commented Jul 13 at 22:03
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The Comet was imfamous for illustrating the risks of metal fatigue, and every plane since had been a lot safer in that regard.
However there have still been more recent cases of abrupt structural failures during the pressurization (climb) phase of flight.
In some notable cases, including JAL123, tail strikes were incorrectly repaired, eventually leading - sometimes a decade or more later - to abrupt aft pressure bulkhead failures.
The resulting explosive decompression tore the tail section off the fuselage, which in turn led to an uncontrolled descent, and a catastrophic impact with the terrain. (These have been covered by multiple commentators, including the Mentour Pilot and Qnxr YouTube channels.)
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$\begingroup$ no explosions though, so don't meet the stated criteria. $\endgroup$– jwentingCommented Jul 15 at 12:01
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$\begingroup$ JAL123 is a much better example than the Comet(s) since it might not have crashed if it had stayed below a specific altitude. The Comets are a poor example since the fatigue was caused by the pressurisation cycle, not by a specific height, and would undoubtedly have crashed eventually, even if restricted to a low ceiling. $\endgroup$– MikeBCommented Jul 16 at 8:43
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$\begingroup$ @jwenting how do you define "explosion" so that it does not include "ripped the tail off"? Given that the OP was talking about "flying too high", they clearly had in mind "popped balloon" rather than "detonated fuel". $\endgroup$ Commented Jul 16 at 22:07
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$\begingroup$ An explosion would be the pressure cabin breaking apart due to overpressure, NOT metal fatigue causing a structural member or piece of skin to break. $\endgroup$– jwentingCommented Jul 17 at 14:17
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$\begingroup$ @jwenting For the Comets, it is debatable, but for the JAL123 failure, the result of the fatigue was indeed a (mechanical) explosion of the pressure cabin; very, very similar to popping a balloon. $\endgroup$– MikeBCommented Jul 18 at 10:27