Lynx Mk7/Gem Engine
 

Hi, hopefully someone can help me out.

Im looking into the Fuel Control Unit and Free power Turbine Governer on the Gem engine.

Specifically the causes of a partial runaway down on the ecu and what can cause it

Many thanks

matty,

so long since I worked on these at RR Leavsden test-beds, that I can remember none of the characteristics. Perhaps if you give a little more detail of what you are looking for, someone here a little more current on the Lynx/Gem may be able to help.

Good Luck!

N1 Vibes

Thanks N1 vibes,

In this case the aircraft experianced a torque mismatch as it started a climb and was unable to correct, pilot then landed on.

torque reading for No1 were low, approx 40%
and torque for No2 was high, approx 90%, with a slightly lower T6/Nh than normal.

the aircrew didnt have enough adjustment to bring to the number 2 down.

Hi matty,

so I'm guessing you suspect a runaway on the #2, but want to understand how the turbine overspeed system works on the Gem? In the civillian commercial a/c maint manuals we do have a basic breakdown of system operation/behaviour, but I'm not sure about millitary manuals.

Do you have a local RR rep that can get a system description/behaviour? On civillian commercial a/c overspeed systems, the engine is normally controlled just below the overspeed threshold, but if the throttle is retarded then the enigne should 'normally' retard.

Unless you have had something else occur that perhaps held the trottle full open - was this the case, or was the engine controllable when power was reduced?

Hope this is of some help.

Brgd's

N1 Vibes

PS - there is a Millitary Aircrew section on Pprune, that I believe some groundcrew may frequent also - could try there