ATA 28-22, A300-600 Trim Tank Isolation Valve

A breif explanation of actuator motors can be found here, rotate.aero/forum/troubleshooting-tips-g...-actuator-motors#189

Checking operation of fuel isolation valve and actuator in shop.



ASM 28-22-00 Trim Tank Isolation Valve

If you have the lockout tool installed, the input shaft "can" be rotated 360 degrees or more (I initially thought it would only turn 90 degrees before a stop was hit).

There really is no way to know if the shaft of the valve is sheared. The indication from the actuator switches for open or close might be working fine for the cockpit indication, but if fuel can't be moved in or out..... sheared shaft.

( Trick to move fuel into and out of tail tank )

I have done that deferral, and it's tricky with a chance to get your ass in a trap!

Stab trimmed to full aircraft nose down (stab leading edge up). If ANYONE is going to be in the cockpit, tag the trim switches and pull the hydro breakers. If it's crew, make damn sure they understand where you're going to be laying and not to dick with anything flight control or hydro related. You stand no chance if that stab were to move down.