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Reversers on in midair

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Is this possible in real life? If so, what would happen to the a/c? I mean about the B-737,57,67,77, A320Series, etc... I have seen shots of some russian airliners do it...Thanks for any info!Z

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If I recall correctly, some years ago a JAL pilot chose to commit suicide in a novel way, by deploying his reversers while on final into Tokyo. The plane crashed into Tokyo Bay. Does anyone else remember this incident?

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This article suggests that deployment of such devices send the plane in to a sort of spin ("rapid torquing"), and ultimately the a/c would crash. I found this on google.http://abcnews.go.com/sections/us/DailyNew...ters110299.htmlI thought that reversers could only be activated while on the ground (by way of devices called "squat switches" which would lock the reversers unless the weight of the a/c against the runway pressed on them), but I guess I was wrong.

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But how is it with turboprops. If I'm right I recall reading about twotters deploying reverse trust (not standard procedure) for ultrashort field landings and/or very steep landings..http://www.emotipad.com/emoticons/Headspin.gif

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Yes I believe there are some older airliners with specially designed twin engine clusters, in which one of the engines on each side can deploy reverser buckets in flight to act as a type of speedbrake to increase descent rates...but I believe this is rare. My father is an aeronautical engineer who did some consulting for one of the airlines over a concern that an inadvertant thruster deployment in flight might happen, I think it may have been for the 747. Anyway, it is bad, very bad, for the airplane should the interlock systems fail for some reason and the thrusters are deployed at any time that the airplane isn't on the ground...regards,

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Hi,the (old) DC-8 was allowed to use 2 of its 4 engines on inflight reverse for speed reduction (e.g. during a high rate of descent).On the props, there are a bunch out there, mostly STOL capable aircraft, able to have a "beta range" on their props: (Twin) Otters, Pilatus Porters...Most prop aircraft don't need it, however, since the prop itself is a huge source of drag when feathered.Torsten

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That's true, then they found that Twin Otters and Turbo Beavers started crashing because of it. They then installed a "safety switch" of sorts, whereby you had to have 40% FWD power before you could get it into reverse. That really screwed up some folks in the beginning as they used to power-back those machines off beaches and whatnot. That became a whole lot more difficult, especially when pulling away from docks where you weren't already anchored.The squat switch was for spoiler deployment. For quite a while there, following the crash/burn of a DC 8 at Toronto (CYYZ) because the spoilers deployed at about 50 to 100 feet agl above the runway, you couldn't even arm the spoilers on approach. Now I believe the systems will allow that, and the squat switch has several redundancies, if I'm not mistaken. The Fokker F28 and BAe 146 use a different type of spoiler system, whereby they are like little flaps that stick out horizontally from the rear of the fuselage and destroy speed more than lift. These are used more to slow them down rather than dump the lift, and are used in the air. I guess they are more speed brakes than real spoilers.Glenn

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I think that in flight reversers are possible on the C17.Joel

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NASA uses Lear Jets in a dive with reverse thrust deployed to simulate shuttle landings, with no engines. The reversers are deployed to ack like the flying brick the shuttle acts like.

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Alrighty now...TOO MUCH MISINFORMATION IN THIS TOPIC...Sorry for the CAPS, but it's needed.1) Thrust reversers are NOT deployable in the air on ANY AIRCRAFT. In the case of the Lauda Air crash, there was a failure of the isolation valves that prevent the reversers from actuating inflight, which caused the reverser to open under AERODYNAMIC PRESSURE, it was not commanded, nor was it forced open. There was simply no pressure in the lines to hold it closed. In the JAL crash, that was speculation. Like I said, you CANNOT command the thrust reversers to actuate in flight. On all Boeing aircraft EXCEPT the 757, the nose squat switch MUST be depressed for reverser operation. On the 757 ONLY, the reversers are linked to the mains as the rudder on the 757 is so large that it allows for enough controlability with the nose off while under reverse thrust, even asymetric reverse thrust.2) The reversers on the early JT-3 and Conway powered DC-8s (-10 through -40 series aircraft) did not deploy in air, only the silencer rings, and ALL 4 could be operated. The later JT-3, JT-9 and CFM powered versions did NOT have this ability. The GROUND spoilers are just that, for the GROUND. Douglas installed the squat switch after an Air Canada crew attempted to use them in the air to slow down (at ALTITUDE, not on approach) and the aircraft broke up under the resultant stresses.3) Reverser deployment is not possible in flight on the C-17 for the simple reason that it'd rip the engines off their pylons. They are fast-acting reversers, so they'll open immediately after touchdown and it may seem like they're using reversers in the air.4) NASA uses specially modified GULFSTREAM II-SP aircraft where the normal target-type reversers (also called bucket reversers) are replaced with enclosed clamshell-cascade type reversers (like on the 727) to reduce the stresses on the engines and remove the buckets from the airstream (they'd rip off if they used buckets), and they have seriously re-enforced the engine pylons to take the stresses. The aircraft also deploy their main landing gear in the "Shuttle Mode", and the flaps and ailerons have been modified into Flaperons to increase the maneuverability of the craft and better simulate the handling of the Shuttle.5) Glenn, you're mostly correct on the F-28/-70/-100 and BAe RJ series aircraft. They still have "lift dumpers" on the wings that will spoil the lift on the ground, the tail is a speedbrake alone like you said. However, most aircraft nowdays have spoilers of a new kind. They're split into two categories- Flight Spoilers and Ground Spoilers. Flight Spoilers are used for speed reduction and roll-augmentation. Ground spoilers only deploy on the ground to dump lift off the wing and keep the plane from bouncing too much. A great example of this is the B-1B. Each wing has 4 spoiler panels. The outboard pair on each wing can be deployed at up to 40 degrees for roll augmentation and 75 degrees as an inflight speedbrake. The inner pair only deploy on the ground once momentary pressure has been applied to the nose gear and are purely for lift dumping. Many commercial aircraft have similar setups.Thanks for reading this guys. Only thing I request is that you guys do some research before providing answers and confirm what you think you know. It only takes a few minutes and saves on a lot of confusion.:)

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Aw thanks for clearing that up Chris, I knew it was some type of Biz Jet that NASA used, but I thought it was a Lear not a Gulf.

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DC8 did it on the two inboard engines, some B727 jocks did it as well when it was first introduced but had some jet upset problems. I have seen it done on the russian TU-154 deploying the reversers on short final on the two outboard engines, but I have also seen them blow a few tires as well upon landing in that configuration.When you feather the prop you are removing the drag induced by the windmilling propeller.Chris de Barros/MYNNBahamasair DHC8-300

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Actually I've just done some research today as I'm sitting here with a maintenance training manual for the learjet 35 :-) To activate the reversers on a lear 35 you first have to arm the reverse-thrust mode, turning on power to the reverse-thrust systems. When the system is armed, sensors coupled to the wheels and thrust requires these to have ground contact/idle thrust set. Not until then are you able to activate the reversers. So I think it's pretty foolproof in that case :-) Although if my memory serves me right, there where a couple of incidents with the saab 340 some years ago with pilots reversing the engines in mid-air, I think they changed the throttle-levers a bit after that... Maybe someone else knows something more about this? Would be fun to know!rgrds/fredrik

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Correction: NASA uses Gulfstream II aircraft specially configured for shuttle training.

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