I need some clarification on the Hydraulic Cut off switch on B3 models.
If you read the Flight Manual of B3 B3+ & B3e and the report in the link bellow they all state that when switching the HYD cut-off switch in the off position the pedals should retain hydraulic assistance.
quoting from the RFM section 7
- A single-body yaw servo
- A load compensating system to reduce, in the event of a hydraulic pressure loss, the yaw pedal feedback loads for an indefinite period.
- The load compensator pressure can only be dumped by selecting the accumulator test switch to TEST position (down)
I flew many B3 from old ones to brand new ones and, as far as I can remember, every time I tested the HYD cut-off switch on the collective the pedals lose hydraulic assistance
Quote from the report
During the extensive system testing, it was found that the operation of the…“HYD” cut-off switch activation, resulted in the yaw load compensator solenoid valve energisation [too], which was not expected by design (loss of the complete hydraulic assistance on the yaw control).
The related wiring configuration was checked and a discrepancy was detected
Surely all the B3s I've flown can't all have been wrongly wired??
What am I missing here?
Fire-Fighting AS350 Hydraulics Accident: Dormant Miswiring
https://aerossurance.com/helicopters...ics-miswiring/