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By alexbrett2
#1836760
So today I ticked off another emergency situation, smoke in the cockpit...

I was heading to Southend to do some circuit training, and was running a bit early so was doing some general handling to get my eye back in and kill time etc. I'd just done a PFL (would probably have made the field), and while climbing pointed myself towards Southend, and decided to pop the autopilot on to hold the heading.

As I levelled off, I suddenly got a whiff of smoke - at first I wondered if I'd somehow flown through my own exhaust, but then looked down and saw there was a modest amount of smoke coming through all around the AP controls.

My first instinct was to turn it off, and then pull the breaker (with hindsight I probably should have gone straight for the breaker as while it was fine, given there was smoke it could have been the case the switch would have been hot enough to burn me depending on where the problem was).

After a few seconds (that felt a lot longer!), the smoke stopped. At this point I turned back towards base, and assessed the situation in my head. My conclusion was the AP was the most likely cause as where it is there's very little else that could cause that sort of problem, and as such I decided to leave the master and avionics on etc, but switch off if any further smoke appeared.

I declared a PAN-PAN and explained the situation to ATC. I then decided it was a good idea to try and ventilate the cabin, so opened up the vents (carefully in case they eg fanned some remaining flames). I also unclipped the fire extinguisher from under my seat and got it out just in case (as a note, it's worth ensuring you know how to do this, as in my case the mechanism wasn't entirely obvious, and had I been panicking e.g. with actual flames this could have been an issue).

An uneventful return and landing (the airport fire service were standing by but once safely on the ground I was able to stand them down).

Subsequent examination on the ground shows it appears a capacitor in the AP decided to commit suicide and turn itself mostly into smoke - it probably therefore produced all the smoke pretty much instantaneously (as the fact the breaker didn't trip would suggest no sustained short circuit etc).

Certainly an 'interesting' first post-lockdown flight anyway...
JAFO, TheKentishFledgling, T6Harvard and 1 others liked this