Reverse thrust lockout

[Just a spotter]

Reading another thread, some posters were speculating on the possibility of the thrust reversers being deployed on one side of an aircraft, and that raised a question for me ...

Is there normally a lockout to prevent reverse thrust being commanded in flight (perhaps a weight on the main main wheels requirement)? If so, suppose a situation with a very close V1/VR, if an RTO was attempted and, with reverse thrust selected the aircraft did manage to become airborne would the lockouts enable/prevent the movement of (particulary mechanical) thrust leavers to be returned to a stowed/forward thrust position?

JAS

[diddy1234]

maybe there is these days but back in the Trident days these aircraft could perform an emergency decent with reverse thrust enabled without damaging the aircraft.

I wonder who thought of that feature when designing the Trident aircraft !

As for today's aircraft I would have thought there would be multiple redundant systems in place to prevent reverse thrusters being deployed in flight.

RD

[dazdaz]

Diddy, yes it can. Air Lauda..............

Lauda Air B767 Accident Report (http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/ComAndRep/LaudaAir/LaudaRPT.html)

Daz

[Intruder]

Is there normally a lockout to prevent reverse thrust being commanded in flight (perhaps a weight on the main main wheels requirement)? If so, suppose a situation with a very close V1/VR, if an RTO was attempted and, with reverse thrust selected the aircraft did manage to become airborne would the lockouts enable/prevent the movement of (particulary mechanical) thrust leavers to be returned to a stowed/forward thrust position?

In the case of the 747, there is a reverse lockout that is actuated by the main landing gear tilt switches. So, the main gear would have to be fully off the ground to go into the flight (locked) mode.

I doubt many pilots would attempt an RTO after rotation with a single engine failure. Also, reverse thrust could NOT be selected until the main gear were on the ground again, so your question about restowing them is moot.

[littco]

I can only comment on the aircraft I fly.

The thrust reversers can only be deployed when the primary throttle levers are in the IDLE position and the aircraft is on the ground. Landing gear squat switches prevent the system being energised when airbourne, there is one on each landing gear and BOTH have to activated to work the system.
In the event of an inadvertent thrust reverser deployment, the throttle feedback machanism will move the affected engine's throttle to idle automatically.

There are also emergency stow switches on the glareshield.. And finally the hydraulic system is a fail safe system, in that should anything fail on the associated hydraulic system, actuators or switches the thrust reversers will fail to the closed position.

This is one type on a specific aircraft, and as only given as an example of how an aircraft may be configured and is by no means meant to be a reflection of any or all there types. I think it will just give you an idea of what safety measures can be employed to prevent such an emergency situation.

[Blink182]

Reverse thrust activated (available ) on the 737 Classics by way of the Rad Alt <15 feet.

[Just a spotter]

Thanks Chaps!

JAS