5 ms·
A tough call. Your solution would disappoint a pilot who actually wanted to slow down ASAP more than Boeing's solution, and might contribute to a runway overrun
by emiliobumachar 8y ago
A tough call. Your solution would disappoint a pilot who actually wanted to slow down ASAP more than Boeing's solution, and might contribute to a runway overrun.
- ravingraven 8y agoNo, it would not. If the engine is shut down moments before touching down it would mean that there would be no reverse thrust after touching down since it takes a considerable amount of time to re-start a turbo-fan (not 60 seconds as OP wrote as the engine is still spooling but still a significant amount of time and I don't think that any pilot would go through the workload and checklists of re-starting an engine during the landing roll anyway). This leads to a longer braking distance. The sane choice would be to not engage reverse thrust at all (until the pilot has reset the reverse thrust throttle) or to only engage reverse thrust once the landing gear has weight on it.
- dmead 8y agohundreds of people are going to die.
- Retra 8y agoOnly if the people in this thread are designing aircraft. Presumably the actual aircraft designers have more experience reasoning through these kinds of problems.
- jagger27 8y ago> or to only engage reverse thrust once the landing gear has weight on it. Having reverse thrust depend on a sensor that could fail seems like a poor choice. What if the landing gear don't drop? Is there a situation where you would still want reverse thrust without landing gear?
- usefulcat 8y agoHow would that work exactly? Surely the engines will be among the first things to be destroyed on 'landing' if the gear aren't down.
- rpeden 8y agoIt depends on where the engines are mounted. There was a Tu-154 that landed gear-up in Greece, then took off again, dropped the landing gear, and landed normally. https://en.wikipedia.org/wiki/Mal%C3%A9v_Flight_262 https://en.wikipedia.org/wiki/Mal%C3%A9v_Flight_262
- jagger27 8y agoThere are plenty of examples of non-catastrophic belly landings. I'm no pilot or aircraft engineer, so I don't know for sure if you'd want reverse thrust in such a situation. https://en.wikipedia.org/wiki/Belly_landing https://en.wikipedia.org/wiki/Belly_landing
- rpeden 8y agoSometimes you'd like to have reverse thrust in-flight if you want to descend really, really quickly. Airliners don't have that feature anymore, but the C-17 and C-5 do. Actually, maybe some ex-Soviet airliners can still do it. DC-8s being used by cargo airlines could possibly still technically do it, but don't use the ability.
- mrguyorama 8y agoSpecifically, it wasn't a design goal of reverse thrust, and it's operation mid-flight was directly responsible for over 200 innocent lives lost[0]. Thrust reversers are very much a "nice to have" feature on turbofan aircraft, with every one qualified to both land and initiate a rejected takeoff at maximum weight without using them, though not without some maintenance after. [0]: https://en.wikipedia.org/wiki/Lauda_Air_Flight_004 https://en.wikipedia.org/wiki/Lauda_Air_Flight_004
- ravingraven 8y ago
- amelius 8y ago> or to only engage reverse thrust once the landing gear has weight on it. Or if the manual override is turned on.