Stuck cowl flaps
-
I was doing the first longer leg with around 700NM, and because of favorable winds I decided to put on the extra oxygen and go up to FL280.
Climbing was done with 36 inches and 2750RPM and 140 knots, 130 higher up, cowl flaps 90% or so open (held the close switch 2 seconds after passing FL150 or so). At 26000 or so I lost both engines briefly when I misjudged the mixture setting, however they came back immediately after correcting.
When I wanted to close the cowl flaps after settling into cruise, I held the switch for 15 seconds. For reassurance I checked the graphics in the tablet, which showed the right one 10% open (the small angled part just touching with the outlining of the nacelle), and the left one fully closed. I then tried to fully close the right one, but it didn't move in either direction. The I tried to open the left one. Doing so, the tablet animation directly jumped to the same position as the right flap (with no animation), and didn't move in either direction afterwards as well. I checked the failures and breakers, which showed no evidence of an issue.
I couldn't move the cowl flaps for the remainder of the flight, including on the ground later on.
Bug, feature, misuse..? Maybe a bug in combination with the flame out? Never had that before. -
I've never seen anything like this before either. I don't believe there is anything that should preclude normal operation of the cowl flaps, apart from the failure, resulting in a popped circuit breaker. I haven't seen this yet, but I assume that there are some people out there with hardware bindings for the cowl flaps, which may interfere. Beyond that, I don't have much else to say, unfortunately. The cowl flap code is pretty isolated, and unrelated to other code. If you see it happen again, please let me know. If it does happen again while you're on the ground, I would be curious to know if you can hear the sound of the cowl flap actuator running out the storm window when they are not moving. That would give us some information about what might be going wrong.
