Originally Posted by
picudo
I had same problem in one S76C+ in Nigeria also. 7000 feet IFR bad weather, both channels AP1 and 2 went to off at same time, I went down looking for VFR conditions flying with stand by horizon (analog), 300 feet I got VFR conditions, copilot tried several times to recover APs as emergency check list demand, pulling CB on top Pilot head, but never wait 5 seconds to back in, and then press APs switches, on VFR conditions we followed step by step emergency procedures, recovered the APs and back home (Port Harcourt)
AP1 and AP2 are isolated systems with different AP computers, different electric sources..... AP systems can't have any failure at same time (AP1 and AP2). It will be easy to understand that this dual AP failure is a consequence.
AP1/2 system will be automatically switched off if the autopilot systems electrical line actuators are not able to maintain selected couplings or if the autopilot system is not able to maintain helicopter's stability (AHRS information vs. helicopter selected heading and attitude is deviated).
The most likely the dual AP failure is a consequence and the root cause could be a blockage or a partial blockage of the flight control system.
Did you make an incident report of this dual AP failure? What was the company's conclusion for this event?
A half an year I was contacted by a pilot who has been able to follow very closely of two different events where (S76) the flight controls temporary jammed during flight. A few years later he was interested in to know what was the company's safety management systems conclusion of these two events. This major operator's (SMS) event dats base was clean and noboby could not memorized that these event has ever happen. It's like this FDR, FDAU, CAMERAS data are missing of 3rd February, 2016 accident. Coincidence?
12th August, 2016 S76C+ total loss of controllability! (six kills) Coincidence?
3rd February, 2016 S76C++ partial loss of controllability? Coincidence?
10th August, 2005 S76C+ total jamming of flight controls and total loss of helicopter's controllability (14 kills) Coincidence?
S76 helicopters are certified according Transportation category (FAA) and should not come suddenly unflyable without any warning - caution!