# Why are commercial flights not equipped with parachutes?

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• Why are commercial flights not equipped with parachutes? Question Overflow

I understand that commercial flights are equipped with life vests. I also understand that most military jets are equipped with ejection seats. It may be costly and technically challenging to equip passenger planes with ejection seats. Having seen air-borne personnel lining up and parachuting out of a C130, what is preventing flights from equipping each passenger with a life-saving parachute? Is it very technically challenging for an untrained person to deploy a parachute, or are there other reasons?

• Parachutes are heavy, expensive, difficult to use and will be useless in pretty much any air disaster.

In order to parachute from a commercial aircraft it would need to be

• in a stable attitude,
• at low speed
• and below about 12 000 ft.

Short of an aircraft losing power to all engines like the Gimli Glider, in which case ditching in the ocean or finding an open space to land is preferable to parachuting your passengers out, I can't think of any other catastrophic failure that would give you the opportunity to let passengers leave by parachute.

That's aside from the difficulty of trying to get passengers, most of whom are panicking, to properly don a parachute and tighten the necessary straps. With a lifejacket a person can still hold onto it in the water if they didn't do the straps right, but the same is not true for a parachute.

• Using a parachute is not a easy job. It require large amount of training, even well trained army para units face more casualties during para jumping. The key odds for using parachute in a commercial airline are

1. Untrained personal using a parachute is much more risky and it may not serve the purpose of saving the life. We may not expect all the passengers of a commercial airliner to have attended a para jumping trainings.
2. Jumping from an airliner at higher altitude requires supplemental oxygen and requires special training.
3. Cost of a parachute is much higher. So, this would increase the cost of ticket and the benefit out of it is significantly limited. This would not be economically possible.
4. The parachutes need to be maintained periodically. Maintaining few hundred parachutes per aircraft would increase the ideal time of the aircraft which leads to cost overruns.
5. It would be literally impossible for children’s, peoples with disabilities to use the parachutes.
6. Opening a pressurized cabin at a higher altitude would result in a decrease in altitude due to heavy inflow of air and would make the situation even worse.
7. Parachute jumping needs a stable platform and a steady aircraft. But, in a commercial airliner which is in dangerous conditions it is practically impossible.

• Almost all fatal accidents happen during take-off or landing, where parachutes would not be of any help.

If the accident happens at a higher altitude, and the aircraft is still more ore less flyable, it is much less risky to attempt an emergency landing and save most or all of the passengers, than risk parachuting them (the other answers have plenty of reasons why it's risky). If the aircraft can't maintain speed and altitude, you don't have the time to parachute even cooperating passengers, much less panicked ones.

• The profit in aviation in 2013 was about \$11.7 billion, on \$708 billion revenues. So the profit margin in global aviation last year was about 1.6%. How do you expect that to work when you remove about 10% of the fare paying passengers by replacing them with 8-10kg parachutes?

That is about $70.8 billion you lose there, every year. Assuming it would safe 240 lives every five year (I am being optimistic here), that's about 1.5 billion per life saved. If you have that amount of money to invest, I can think of more efficient ways to make aviation safer than by adding parachutes which might help in a crash once every five to ten years. • There are several good answers above, but another important thing to consider is that it's impossible to jump out of a commercial airliner (except the 727, which is rarely still found in passenger aviation) while in flight, unless a hole has opened in the fuselage or it has otherwise become depressurized. The doors have to be pulled in to open, which is, for all practical purposes, impossible while the airframe is pressurized. From a safety perspective, the additional risk of allowing the doors to open in flight far outweighs the potential benefit of letting people bail out in the narrow range of circumstances that that would even be possible. This is because it would require the doors to open outward, which opens up the possibility of them blowing out in flight. Back when airplanes were designed that way, several people died from explosive decompression due to a door blowing out. This was a problem both on the DC-10 and on early 747s. A further issue to consider is the locations of the exits. The reason that it was possible to bail from a 727 is that it had an exit in the tail cone. No other passenger aircraft that I'm aware of has that. Many military cargo planes (like the C-130 you mentioned) do use ramps in the tail, though, and that's where people jump out from in those aircraft. If you try to jump from a side door in a jetliner (which are the only doors that exist in most modern jetliners,) you'll likely be promptly cut in half by the horizontal stabilizers moving through you at 550 mph immediately after stepping out the door. Of course, this would also damage the horizontal stabilizer, which would then quite likely result in the death of everyone still on the plane, due to loss of pitch authority. Of course, if you jump out of a door in front of the wings, you might be killed by a wing or an engine rather than a horizontal stabilizer, but the results are still equally undesirable. Jumping out of side doors is possible (and normal) for the much slower aircraft used for skydiving, but not for a passenger jet moving 550 mph. I don't have time at the moment to run all of the numbers, but one thing did come to mind that helps in the comparison: terminal velocity. Terminal velocity is the point at which the upward drag on a falling object is equal to the downward gravitational force and, thus, downward acceleration due to gravity stops. Where this provides some insight on this question is in the comparison of forces. Terminal velocity for a human is about 120 mph at low altitude. This means that the wind speed required to equal the gravitational force is approximately 120 mph at low altitude (of course, this can vary depending on the shape and mass of the person in question and their position relative to the airflow.) Since drag is proportional to the square of velocity and linearly proportional to air density, this means that a 550 mph wind at an altitude where air density was roughly$\frac13$of at the surface would exert a force with a magnitude of about$(\frac{550}{120})^2(\frac13)\approx7$times the magnitude of the gravitational force. So, at least initially, you'd be accelerated backwards about 7 times as quickly as you'd be accelerated downwards by gravity in these conditions. Aside from the fact that being accelerated backwards at around 7 Gs is going to hurt, there is a very real possibility of hitting any part of the aircraft that happens to be behind you. Also, as mentioned in a comment below, it would actually be entirely possible to be accelerated upwards (at least briefly) with that much drag, depending on the average angle at which your body is deflecting the wind stream. Another consideration is that the windstream itself will be faster than the true airspeed of the aircraft itself around certain parts of the aircraft, including around the fuselage and above and behind the wings. Furthermore, the airstream is not always exactly parallel with the aircraft. It can have an upward component relative to the aircraft around certain parts of the airframe while it almost always has a downward component relative to the aircraft behind the trailing edge of the wings. Also, if the plane itself is descending, there will be an upward component of the airstream relative to the aircraft at almost all points, except maybe right behind the wings. So, long story short, a lot of factors play into this, but things aren't looking up for the prospective jumper. • The main reason that parachutes are not used is that there are very, very few aircraft accidents that occur with enough time to actually use one. In fact, I'm not sure that there have been any. Below are a couple examples that you may originally think that parachutes could have been useful on because they initiated from a high altitude. # Air France 447: The short version is that they stalled the airplane at cruising altitude and held it in the stall until it crashed into the ocean. Let's consider that the amount of time from the peak altitude of the aircraft until impact with water was only 3 minutes and 21 seconds. Let's be very generous and say that everybody on board immediately knew that the aircraft was going to crash and there was nothing that the pilots could do. This gives the panicking passengers just over three minutes to get their parachutes out of storage, properly secure themselves into the harness (which, trust me, isn't as easy as it sounds even if you know what you are doing and are in the proper frame of mind), all while in the confined space of an aircraft seat with everyone else around them doing the same thing. After that, we somehow need to open the doors and get people to orderly line up and exit the airplane without freaking out and getting scared. Seriously, 99% of the people won't even get their parachute on (correctly) in that amount of time, much less the far less time that they would really have before they knew about the crash. The reality of the matter is that the pilots are doing everything possible in an emergency situation to not crash in the first place, and if they are successful (which they usually are) then having everybody jump would have caused many more problems than having the passengers stay put in their seats with their seatbelts on. In this particular crash, the pilots didn't even realize that the crash was certain until four seconds before impact when one of the pilots verbally stated "we're going to crash". Up until that point they were focused on recovering the aircraft and probably would never even have given the evacuation order had it even been available. # Gol Transportes Aéreos Flight 1907 This was the mid air collision over Brazil. At least in this case, it became certain pretty fast that the aircraft was out of control and was going to crash. A small quote from the accident report describes what happened immediately after the collision: Immediately after the collision, PR-GTD started a fast descending spiral, similar to the maneuver known as spin, which by no means could be recovered or controlled by the crew. During the vertiginous dive, the aircraft was submitted to extreme aerodynamic forces, around all the axes, with positive and negative accelerations, well above the maximum resistance limits of the operational envelope. As a result, there was an in-flight break-up of the aircraft in several pieces of different sizes, which hit the ground. The increased G forces on the airplane were very likely to the point that people couldn't stand, or at the very least would have a much harder time doing so. Trying to put a parachute on in these circumstances would be even harder than in the previous example. Total time from the mid air until impact with terrain: Estimated 1 minute 5 seconds. Each of these scenarios assume that even if there were parachutes on board and people were able to don them correctly in time, that they would be able to use them to survive. Here are a few additional factors that would come into play in the unlikely event that they were able to even get to this point: • Many modern aircraft doors can not be opened in flight. • If this happened at high altitudes, everybody would need oxygen as well or they would pass out. • The passengers that actually make it out of the airplane do not know how to fall in a stable position, and the parachute is very likely to become tangled while opening as they are tumbling through the air. • The passengers would need to actually deploy the parachute manually while most probably in a panicked state of mind. • There would be many injuries during landing. • Once they did land, they would have no survival gear. This is particularly a problem over the open ocean or in the jungle (where these flights have been). Considering that even in most accidents the aircraft is still landed in a somewhat stable manner and most people survive, having a couple hundred people bailing out of an aircraft would most likely cause more harm than good, even if they could solve all of the technical issues. If the decision is made to evacuate and then the pilots get the aircraft back under control, it would be even worse! • From basic high school physics, assume someone is 1.7m tall and steps out the plane rather than 'diving'. The equation: $$Distance~(from~standstill)=\frac12Acceleration\times{Time}^2$$ And substituting: $$1.7m=0.5\times9.8m/s2\times{t}^2=0.59s$$ The panicked passenger would take 0.59 s for his head to be safely clear of any decapitating wires that happen to be level with the bottom of the door. If he immediately decelerated to 0 mph forward motion (I need someone else to figure out that part) he goes backwards 130 meters before he has dropped to safety. But even if it takes him 0.4 s to decelerate, that still leaves 0.19 s stationary in relation to the plane when his head isn't safe. That is about 42 meters, not counting the distance traveled while he is slowing down during those 0.4 s so I'm inclined to support @reirab on this one. • Qualification: I worked at a sport parachute center as an instructor for 10 years and I hold an FAA Master Parachute Rigger certificate. I believe that qualifies me as an expert on the subject. The majority of the above other statements here are correct. In summary: • The door of a pressurized passenger plane cannot be opened in flight for the stated reasons. • the door of most larger passenger planes cannot be opened in flight after you depressurize the cabin because they swing forward. Push a sheet of plywood against a thunderstorm-grade wind and see how well you do. Now multiply the wind speed by 5. • even if you blow the door out with explosives, the chances of an orderly exit are slim. At airliner speeds an orderly exit is critical if you expect to survive the jump. Street clothes will be torn to shreds. Oh, and it's COLD up there. • you cannot depressurize an aircraft over 12,000 feet altitude without the passengers passing out rather quickly. If you can control the plane down to this altitude, you don't need the parachutes. • it is extremely difficult to exit an unstable aircraft that is built for sport parachuting (in-flight door, suitable handles, door already open). If the plane is spinning and you are beside the door you might get tossed out and then struck by other parts of the airframe. If it's a larger plane and the door (or you) are away from the current axis of rotation, good luck. Yes, jumpers have successfully exited a crippled jump plane. None of them want to try it again. • modern sport parachutes use steerable ram-air canopies. Jump one of these without any training and you will hurt yourself landing. Most emergency parachutes are round. Jump one of those without any training and you will break something when you land. 200 untrained people jumping ram-air canopies all at once will result in a number of collisions and entanglements, which are typically fatal for all involved. • exiting an airplane below 1000 feet is really not practical. I would do it IF a) the plane is currently under control; b) landing is not practical; c) It's really 1000 feet, not less; d) I'm sitting beside the door. Possible scenario is the engine goes boom and I know there's nothing but rocky land ahead of us. Of course my gear is already on my back ready to go, and I know how to use it. There have been many cases of a jump plane experiencing engine problems on the way up. By the time the pilot turns around, the cabin is usually empty. There have also been cases where jump planes have crashed on takeoff. None of the (very experienced) jumpers on board thought about anything other than tightening the seatbelt. Points I disagree with: (although they do not change the outcome) • Emergency parachutes (seat-pack types) are available for far less than sport rigs. Maybe$1,500 each. Weight around 8-10kg. Putting a purpose-built one on would be not much more complicated than a 4-point harness. This was seriously considered back in the 1950's - aircraft seats were designed with parachutes built in. Planes were neither pressurized nor fast back then. Think DC-3 era - the DC-3 makes a great jump plane, I have used one a few times.

• maintenance costs would be no more than the escape slides, flotation gear or other similar equipment.

• The technical answers have been great, but there is one very simple answer to why airlines don't provide parachutes:

It implies that commercial flight isn't safe

For the similar reason that car's don't protect you to the nth degree, many people will stop using them as they'll realise just what they are actually doing, and as pointed out in another answer the margins are so low that a 10% drop in passengers would be ruinous to many airlines.

• Prelude: While studying for being airplane engine engineer in university I took 3 years of special military course where been taught to be military aircraft mechanic. Also forgive my possible incorrect tech terms as English isn't my native language.

As OP has stated one on hand those systems are expensive, but this isn't the main point why those are not used in commercial aviation. There are two points to consider:

1. Those systems are heavy. We all have seen how on commercial airlines they weigh your luggage. This is done for a reason - the airplane does not have infinite weigh capacity. If we equip standard commercial plane like Boeing 777 with eject seats there will be no free weight capacity for either passengers or their luggage. One such system (the one I have studied) weights appx 80-90 kg. Seeing standard commercial seats I'd say their weight is no more than 10-15 kg (anyone correct me if I am wrong here). However installing such systems could be done for example on private airplanes where the number of passengers is limited and thus there is some free weight capacity, but it still would be bad solution due to second point.
2. In order to survive ejection procedure one should have perfect health and wear special suit. Let's start from suite - you've probably seen in movies that military pilots wear special suits, those suits are designed to handle two things that happen to you during flight - depressurization and extreme acceleration. Not sure if in any movie it was shown, but this suite actually consists of network of tubes and pads that are being inflated with high pressure air through connection in pilots seat. Why there is a need in such suit? I won't talk about normal flight in those suits as we are talking about commercial airline, let's see what happens during ejection. When one is ejected, their seat is basically being launched with a rocket engine, in order to prevent damage to pilot/passenger from any parts of aircraft, he/she should be moved away of it very quickly, this means very high acceleration rate. On the other hand our body contains big amount of liquids. Now imagine what would happen if suddenly kick a glass with water? Inertia will hold liquids from moving together with glass, that means all blood in case of ejection will move down in our body - 1) leaving our brain without oxygen supply; 2) destroying blood circulation systems in bottom half of our body. With special suit (that with extra pressure on our body balances this effect) we can make sure that our body will not burst itself out with high pressure blood from below chest level. Although I myself never went through such examination, while studying we learnt that one of very important health checkups for pilots is their cardiac system, means that their heart and blood tubes will be able to handle such an extreme procedure (and this is why running is an important part of military training as it strengthens whole blood circulation system). Still having said all of that about military pilots, more than half of them while will survive ejection procedure, will blackout for some time due to low oxygen level in brain. Also as we were told while studying, even with all this training and equipment people who once went through ejection in mid-air are usually not piloting after that due to damages their body suffered (this info maybe outdated as eqipment we learnt was about 10 years old at that time). Now compare trained military aviation pilot equipped with compensation suit to the average commercial airline passenger who perhaps smokes, eats high cholesterol food and doesn't do much sports ;) What do you think will be chances of survival?

• As an alternate answer in that you can still get parachutes on a plane, even if the airline doesn't provide them...we had a related question over on Travel.Stackexchange. While, as you noted, airlines don't typically provide parachutes, the TSA specifically allows you to bring your own.

Are parachutes allowed on airplanes as cabin baggage?

Short version from the TSA:

You may bring skydiving rigs with and without Automatic Activation Devices (AAD) as carry-on or checked luggage.

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• I understand that commercial flights are equipped with life vests. I also understand that most military jets are equipped with ejection seats. It may be costly and technically challenging to equip passenger planes with ejection seats. Having seen air-borne personnel lining up and parachuting out of a C130, what is preventing flights from equipping each passenger with a life-saving parachute? Is it very technically challenging for an untrained person to deploy a parachute, or are there other reasons?

• Per FAR 91.307: Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft carrying any person (other than a crewmember) may execute any intentional maneuver that exceeds... So if I'm flying aerobatics solo, I'm not required to have a parachute. But if I have a passenger, both are required to have one. What is the rationale for that? I suppose that in something like a Super Decathlon, where the pilot must exit the plane before the passenger, it would be senseless to have one for the passenger but not the pilot. But is there anything more to this?

• There was another question that asked why commercial flights don't have parachutes. The almost ubiquitous response was that the parachutes would be useless because: Most accidents with commercial airliners happen on take off and landing, and there is no time to parachute. In order to get to a position where 100+ people can successfully jump out, you'd most likely need to descend some 20,000 ft... out? It seems like a somewhat practical solution, yet I have never heard of anyone doing it. Why do pilots often try to find a road to land on or a lake to ditch in when trouble strikes instead

• Some light aircraft now have airframe parachutes. If a pilot does have to pull the chute on a Cirrus (for example), is the aircraft flyable or at least repairable after landing or is it a write-off? What G forces are involved in the impact? I realize that there are lots of possible variables here, but let's assume that the parachute deploys correctly and in plenty of time for a stabilized...). The airframe, seats and landing gear are all designed to absorb the impact energy.

• Recently I was checking in to a flight and was asked if I'd like a window or aisle seat as usual and choose a window seat. I was then told that there are no more window seats available but I could get an aisle seat without someone sitting next to me and then just take that window seat. The plane was an ATR-72 so the rows were 2+2 seats. I know about weight distribution to the front/back but I couldn't come up for a good reason to do this. What could be the reason for not giving me that apparently free window seat right away?

• On commercial flights, in part of the pre-flight safety demonstration, you're told in the event of a crash, not to inflate your life vest until you're outside the airplane — why is this?

• I regularly fly a DA42 4-seater equipped with a G1000 system. Sometimes my passengers in the rear seats complain that the radio volume is too loud for them but it is OK for me (intercom is just right for everybody). Reason probably is that I am using a very different headset than them which I assume has a higher impedance and thus requires more electrical power for the same audio volume. If I turned down the COM volume it would be too quiet for me. I wonder if there is any trick to adjusting/balancing the volume in such a setup.

• When the Cirrus was first introduced, it included a Ballistic Recovery System, which shoots a parachute out the rear of the plane that can save a plane and its occupants when something goes wrong. Seeing as how this technology has been honed over the past decades, why don't all new planes incorporate this feature? I would think that any drawbacks outweigh the benefit of not losing one's life when something happens unexpectedly.

• that in the current design, there's a great deal of space wasted over the passengers' heads. And that many of us passengers already do our best to sleep through flights. Hence my question: Is there any reason... (or cargo restraint webbing? I'm not sure I'm joking) could handle the remaining risk. No, I don't really think it would be commercially viable ... but I'm wondering whether folks who actually Know Something about aircraft safety and loading think it's technically viable.

• I've always wondered, what are those dual-layered (bonus: sometimes they have a little <2mm hole, why is it there?) windows commercial jets put next to their seats made of?

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