A few days ago I read an article on the “Ars Technica” website. Just by reading the title*1 and seeing the first image, I got really excited.
In case you have not already read it, the article says that Airbus filed an interesting patent *2 two weeks ago. With this patent Airbus is trying to speed up the passenger boarding process, thereby increasing efficiency and lowering costs.
But what immediately popped into my mind was passenger safety, or what could additionally be done to save people’s lives in the event of an emergency — a parachute for the crashing plane.
As the passengers' cabin is detachable, it will be significantly less heavy than the combined weight of the cockpit, wings, engines, landing gear, and tail, including the fuel and passengers' cargo.
The Boeing 747-200, for instance, can carry between 366 and 460 passengers. The weight of the empty airplane is 380,510 pounds (172.570 kg). If we assume that every passenger has an average weight of 200 pounds (90 kg) and that they may have cabin baggage of an additional 30 pounds, their combined weight is equal to 230x460 = 105,800 pounds. To this number we have to add the weight of the detachable passenger’s cabin with all its seats and other parts. Without a calculation I will estimate that number to be an additional 100,000 pounds. All together that should give us a rough estimate of 100 U.S. tons. If you wish to do a more precise calculation, check the following page.*3
Although the number is approximated, keeping in mind new materials like newly invented aluminum alloys and carbon fiber composites, this number should not exceed the approximated weight and should probably be lower.
With that number in mind, emergency parachutes become a feasible idea.
This idea is especially feasible considering that, for quite some time, Russians were dropping T-80 tanks using parachutes combined with retro rockets. In other cases, they were using a parachute combined with large air bags below the tank to safely land the vehicle on the ground.*4 The weight of one T-80 tank is around 50 U.S. tons, which is half the weight of what we estimated for the entire replaceable cabin cartridge along with the passengers.
Combining a few concepts like parachutes, retro rockets, and airbags could create a solution that saves lives, maybe not in the case of a terrorist attack with a bomb or a rocket, but perhaps in the case of an engine failure.
Additionally, as it is significantly lighter, additional engineering could make the replaceable passenger cabin floatable. In case of an emergency crash landing on water, the most important part of the airplane would not sink, significantly increasing the chance of passengers' survival.
Pondering along similar lines, I remember that pilots of jet fighters, while ejecting from the aircraft, can suffer neck or leg injuries.*5 How feasible would it be to have a detachable/ejectable cockpit?
Notes & References:
1. Airbus proposes new drop-in airplane “cabin modules” to speed up boardinghttp://arstechnica.co.uk/cars/2015/11/airbus-proposes-new-drop-in-airplane-cabin-modules-to-speed-up-boarding/
2. Method for boarding and unloading of passengers of and aircraft with reduced immobilisation time of the aircraft, aircraft and air terminal for its implementationhttp://pdfpiw.uspto.gov/.piw?docid=09193460&PageNum=1
3. Component Weights calculationshttp://adg.stanford.edu/aa241/structures/componentweight.html
4. Dropping Russian tank using parachutehttps://www.youtube.com/watch?v=GulrDxyId2k