What is the maximum height for deploying a parachute?

Question

i see a detachable plane cabin project .When an airplane crashes, the human toll is generally heavy. Based on this observation, Vladimir Tatarenko, a Ukrainian engineer who worked in particular for the Russian aeronautical manufacturer Irkut, have a idea:the pilots join the passengers, and the cabin is ejected from the rest of the plane. The landing is carried out smoothly thanks to a system of parachutes and floats. The inventor of the concept is very serious, he even filed a patent in 2014 and invested $ 50,000,he he is currently looking for investors.

This concept of ejectable aircraft cabin is not yet ready to arrive on the market. If two Ukrainian aeronautical universities are working on the development of a model, the engineer is currently on the hunt for investors. Eight years will be needed to develop its concept, which is estimated to cost nearly two billion dollars.

The additional cost generated to equip the aircraft is estimated by Vladimir Tatarenko at "a few percent " of the list price of an aircraft, but 95% of passengers would however be ready to pay for their plane ticket 15% more if their plane was equipped with an ejectable cabin . A system nonetheless of no help in the event of a bomb on board or a missile fire.

But I am not sure that this is achievable,because of weight,height...for the weight they claim that it's possible with new ultra-light materials based on carbon, but which prove to be very expensive.The last limit concerns the flight phase during which the crashes take place. Between 2004 and 2013, out of all the crashes, 14% took place during takeoff and initial climb, and 47% took place during the final approach and landing. All these flight phases taking place between 0 and 1000m altitude, the opening of the parachutes may be too late to save the passengers.

what is the maximum height for deploying a parachute? is it technically possible? knowing that Parachutes for aircraft already exist and are developed by several companies including Ballistic Recovery Systems (BRS) which has already saved 350 lives thanks to its system. The product consists of a parachute, stored under the fuselage and which deploys after activation of a joystick by the pilot. A sail of some 220m² then comes to deposit the entire device on the ground. This solution already equips several models from the manufacturers Cessna and Cirrus which can transport from 2 to 5 passengers.

https://brsaerospace.com/

Answer 1

Not for large passenger aircraft. Single engine failure flies on. 2 engine failure? I'd rather have a (shielded) 3rd engine, perhaps doubling as a very robust APU. Probability of a major structural failure in a commercial aircraft is not high enough. Both pilots incapacitated, same. Saving people from a loss of control due to spatial disorientation or a spin, not in an airliner, but very good for GA aircraft.

Military or cargo transport, possibly, which would involve dropping an entire modular unit instead of pallets. The application could be an emergency shelter or command post in a remote or natural disaster stricken area.

As early space capsules have shown, parachutes are workable from very high altitudes and great speeds (with drouge chutes). There is no maximum altitude.

Detachable, interchangeable modules for cargo and passengers would certainly make a plane more versatile, but probably could more easily be slid off by opening one end, like a 747. The attachments to the frame of the aircraft for 2 separate external units may be much weaker than one semi-monocoque fuselage.

Large helicopters such as the Sikorsky S-64 Skycrane utilize a similar concept of a flying frame/cargo module arrangement. This idea may be best worked backwards from an application.

Answer 2

“What is the maximum height for deploying a parachute?” Probably somewhere in the neighborhood of 60,000 feet MSL. I have no citation for this opinion. Based on what I have seen and experienced, there will be some limiting factors that will not make a parachute effective beyond that. As a matter of fact, a better plan would be to fly the plane as long as possible to a lower altitude and speed before deploying a parachute above a safe landing zone. Or, (less ideally) you may deploy a drogue chute until you reach a lower altitude and speed before deploying the main chute.

One limiting factor is air density. Most jumpers who have parachuted higher than the 100 millibar pressure altitude (roughly 51806 feet or 15790.5 meters) have cited the same thing. There is a lack of directional stability and control due to not enough air resistance. A small drogue chute is necessary just to keep from tumbling uncontrollably. Deployment of a parachute in this state would be extremely dangerous. Even once you are stabilized, this same phenomenon might make it difficult to inflate a parachute once it has been deployed. Skydivers have a similar issue when their pilot chute is not thrown far enough away from their body during deployment. The pilot chute gets caught in the aerodynamic “burble” in the wake of their body.

A second limiting factor is speed. If you use a drogue chute to stabilize the free fall, it has to be large enough to produce sufficient drag to slow the falling object to a terminal velocity that the main chute can handle. Otherwise, you risk stressed seams, blown gore panels, snapped suspension/shroud lines, or the failure of the riser connection points. I’ve seen all but the riser failure on military airborne operations at speeds as low as 160-190 knots. I’ve seen the aftermath of even the riser failures on airborne drops of equipment at much lower speeds. And, if you increase the strength of the parachute used so that you can handle higher speeds, you would have to increase the parachute’s weight.

A third and maybe the most important limiting factor is safety. Deploying a parachute at a higher altitude may be of equal or greater danger than the underlying emergency. As a pilot, your number two concern has to be for the lives of your passengers. Your number one priority has to be for the lives of those on the ground, IMHO. If I had no other choice, I’d rather crash my plane in an open field than in a densely populated area. You give up more and more of that choice the higher you deploy the parachute.

I’ve seen experienced jumpers crash T10C and -1B parachutes into trees, buildings, power lines, etc. even at deployment altitudes under 2000 feet. I, myself have had an accidental deployment of my reserve chute when the retention pin broke upon exiting the aircraft at 17,000 feet. I was able to steer the ram-air canopy back to the dropzone. But, the deployment bag and pilot chute ended up drifting out of site.

The higher you deploy the parachute, the more likely you will be at the mercy of the winds. A rogue drogue or pilot chute may not cause too much damage. 350 pounds of soldier with gear may cause much more damage (especially to themselves). Even a 1380-2550 pound single engine GA aircraft may cause an acceptable level of damage. A fuselage for 100-400 people falling in a populated area will be catastrophic.

As for the minimum amount of altitude for safely deploying a parachute, I’ve always heard the rule of thumb from riggers and jumpmaster to be three times the length of the parachute itself.