i heard about a SAAB 340 from some operator way back in the day - apparantly they were high on the approach and slightly fast, the fairly new captain lifted the power lever triggers and pulled the engines into beta to help slow down the speed.
as a result the props did weird aerodynamic things and went into an uncontrollable over speed. the prop RPM gages were pegged off the measurable scale of the gage and as a result the torque, Ng, and ITT also went way out of the envelope which resulted in complete destruction of the engines within a matter of seconds.
they landed the plane without any engine power and ran off the end of the runway... nobody was hurt but in response to this incident an automatic flight idle stop was installed on all saab 340s to prevent the levers from being moved below flight idle when there is no weight on the wheels.
I do know that there is a certain model of king air that can be pulled harmlessly into beta in flight, but pilots are advised against this because of the 1 in a million chance that the props STICK in beta in flight!
It is possible to back up a large aircraft on the ramp using the "reverse" on the props but the biggest risk in doing this is when you try to stop the aircraft is very likely to fall on its tail. part of the C90 training that i went through a couple of years ago focused on "power backs" they told us NEVER to do it... but if we HAD to here is how to do it without breaking anything. ::)
in real life the reverse of the props is only used as an aide to breaking on the landing roll out, or to control speed during taxi, it is really not used in any other realm of flight.
To change track slightly, the C17 Globe Master can use thrust reverse in flight for tactical drops enabling I believe a descent rate of up 20000 feet per minute be produced. I would like to see it, but not be on board.
Matt
There is a video of that on flightlevel350
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