T/R Failure
Well ... as many UK pilots know, I've been lucky enough to cope with three T/R failures. (in 14,000 hours tho') The first in 1975 in an Enstrom 280 Shark at Shoreham when the T/R drive shaft sheared at around 300 feet in the climb out. As a low time rotary my instinct was to dump the lever and when I found myself on a reciprocal heading, and about to make contact with the aerodrome, I raised the lever and shoved the stick forward. The machine stayed upright in a 60 knot 'run-on' landing. I spent some time studying the incident and having established a corrective sequence of control handling I began teaching a recovery procedure to interested pilots.
Following a long briefing on the planned handling, in the air exercise, I have my pilot place both feet flat on the cabin floor and by observing the airspeed selected and the power being used, I simulate the relevent yaw angle as I can best determine. The exact yaw angles may not be correct, but the required corrective handling is.
I still teach T/R failures and offer the following procedure based on my experiences ....
T/R FAILS - airframe yaws rapidly RIGHT. Actual rate of yaw depends on power and airspeed at the time of failure. RESPONSE .... Collective lever is lowered with cyclic forward and LEFT to achieve say 60 - 70 knots. Yaw stops and commences slower yaw LEFT due to transmission frictions. Allow airframe to yaw LEFT to the 10 0'clock position when lever is then raised slightly using RIGHT cyclic. Continue lifting lever to bring nose RIGHT to not more than a 2 0'clock position while maintaining 60-70 knots attitude. As airframe passes the 12 0'clock position cyclic is reversed to LEFT as nose settles at 2 0'clock. Carry out standard emergency checks and endeavour to maintain speed and a stable 2 0'clock position in level or descending flight. (Largely depends mainly on A/C weight)
Select the best available emergency landing site using cyclic to achieve a 400 to 500 feet final position. Once certain of reaching the LS, lower lever (cyclic from LEFT progressively to RIGHT as the 12 0'clock position is passed) to commence descent allowing nose to return to the LEFT 10 0'clock position maintaining 60-70 knots. (Lever down/cyclic right ... lever up/cyclic left is a good dictum.)
Maintain descent in 10 0'clock attitude until A/C is around 20 feet above the landing surface when lever is raised (nose going RIGHT) using progressive aft cyclic to minimise skid contact speed. Allow nose to pass the 12 0'clock position until 2 0'clock when throttle is closed smoothly and fully ... nose commences LEFT yaw and as it passes the 1 0'clock position, cyclic is pushed firmly forward to make skid contact at a 'dead ahead' 12 0'clock position or as best as can be achieved and at the lowest ground speed. Depending on skid contact and grip, nose may well continue to yaw LEFT, possibly to a 180 degree 'skids in contact' turn as happened on my third T/R failure experience.
The above notes are offered more as a discussion point on the general handling and need to be modified for type variations. (obviously read left for right etc on the French types) I appreciate the vast level of similar experience out there and I'm sure our thread will benefit from other views, but the above suggested handling worked for me at Cranfield 1986 and Biggin Hill in 1999 with nil airfame damage.
Naturally I'm happy to enlarge on any aspects of the above as required.
Dennis Kenyon.