Question: Do you think that some of the special features of the boeing C17 like revesing up hill or refuelling in flight is something we're ever likely to see in commercial planes?

Al Bartlett answered on 22 Mar 2012:

Hello Meganl56,

I don’t think so Megan – Things like in-flight refuelling and engine reversing are very expensive additions to an aircraft.

Inflight refuelling – When refuelling in the air we need a tanker aircraft to carry the extra fuel – This is not only expensive but quite a dangerous process – Fuel is very flammable and the military pilots that are qualified to do this have trained for yearsto be able to do it safely. This is unlikely to be something that the airlines would pay for, it would also increase the price of your ticket. If we were able to refuel commercial aircraft in flight it would mean the ability to fly from London to Australia non-stop – this would also mean about 20 hours of flying in the same aircraft in the same seat. Im not sure passengers would be happy with that and would probably prefer to stretch their legs in Dubai or Singapore!!

Reversing – Most commercial planes already have a system like this but only use it for slowing the aircraft down rather than reversing it. An aircraft engine uses its exhaust to propel the aircraft forward. When the aircraft lands, it activates a system called ‘reverse thrust’ which effectively directs the exhaust gases to the front of the engine meaning that all the thrust is now facing the other direction and helps to stop the aircraft. The ability to use this system to reverse requires incredibly powerful engines that are too expensive for commercial airlines to afford – also, runways for civil airliners are significantly longer than those found in the middle of a war zone so the need to stop quickly is not needed.

Hope this helps you