The National Transportation Safety Board Preliminary Report on the July 26 fatal Pilatus PC12-47E accident in Wyoming does not offer much in the way of new information. It supports previous reporting that the single-engine turboprop, with seven on board including the owner-pilot, crashed after an apparent loss of autopilot function followed by a loss of control.
Pilot Debrief and Blancolirio both covered this incident and another very similar one where the autopilot of the PC12 disconnected and the pilot lost control in bad weather. It appeared that neither pilot was prepared to take command of the aircraft when that happened. It as been my experience, that the auto pilot will hand you the plane at the worst possible time and you better be able to hand fly it when that happens.
It is inconceivable to me that the loss of an autopilot in IMC could result in total loss of control of an aircraft and ultimately its loss. It’s as if the pilot never hand flew the aircraft in the soup. What am I missing?
You are correct. By the time the autopilot hands you the aircraft it has moved one or more trims to one of their max extents and there is still too much force for the auto pilot to counteract. When it finally disconnects the aircraft will violently pitch and/or roll. The pitch is usually downward pinning anyone not buckled up and all loose items to the ceiling. If unexpected and IMC, good luck.
Valid point. IF the plane was still controllable the AP would still be flying it. This seems like a worthwhile thing to practice in the sim or in VMXC with an expert pilot/instructor aboard.
We did practice it in the sim in various models of aircraft. We had to ignore indications that the situation was developing and when it happened you were not that surprised and ready to react. Sim practice is not that great because you are on high alert for problems all the time.
The ultimate lesson here is the need to be constantly monitoring one’s airplane in unstable air as to how it is responding to outside pressure and temperature in time to pickle automation and take over manually. It’s a full time job which requires a high state of mindfulness, and not only the ability to take over manually but a confidence and even an eagerness to do so which comes only with a high level of manual currency.
You’re missing nothing. It is a regrettable truth today that even among professional pilots, basic flying skills are sometimes not what they should be.
Don’t know the service ceiling, but from what I recall of weather could have pushed trying to top weather and when finally penetrated didn’t have a lot of performance margin left. If not proficient hand flying, having the autopilot dump it on you single pilot when potentially battling severe turbulence, icing, disorientation, panic in cabin and/or cockpit, all while nibbling at stall not a good mix.
Any flying machine can be overmatched, up to PIC not to put it there.