LE Flaps
On the CX Classic with RR RB524's the LED's DID NOT retract on application of reverse thrust. QF Classics DID. The reason they used to on some B747's was because, I believe, the possible damage to the LED's by hot stream gas flow being reversed. On the RR only the cold stream is reversed. CX believed that it was less costly to prolong pneumatic drive motor life by not retracting the LED than repair any damage they may incur from reverse operation. QF obviously did not share the view of CX, just as they differed on Rudder Fine Steering. Active on the CX aircraft, de-activated on the QF aircraft I was given to understand.