Have a prop on a -16 that will not pitchlock. Prior to us getting the plane for ballistic foam install, the squadron had the same problem. They changed pitchlock reg., valve housing, then the gearbox sh*t the bed and the prop was seized on the shaft so they r2\'d the tq meter, gearbox, prop/dome. Sooo. They had a good pitchlock after all of that...once...so it could get here.
We have tried all manner and techniques IAW pubs, and otherwise without success. It will overspeed without a problem, but does not even think about locking.
Re-Indexed about 6 times (1x=2 then 3 master).
Tried getting low/ref tq at about 97% then going to 1077 before locking and hitting gov switches...no dice.
Tweeked fuel topping to the high limit 105.6/1600pph. The beta is at 6.0.
Syncrophaser was R2 for a different problem on a different engine.
Thought that it may be in mech gov the whole time, but droop checks from the new sync are good both as master and slave (problem is on no.2)
It has been suggested by the prop guru at PPI that we try to pitchlock in auto. Fuel topping has been confirmed at 105.6 (autotach) so there is not 110 worries. Thinking was that TD had to put above xover, and that coming back to ref. rpm was below lights out. Xover checks have the TD taking as normal, and the sucker is about 45rich.
Any takers.....?