This has happened to me even at the beginning of a flight, if the temps in the hangar have gone from cold on a previous day, to warm on flight day. I guess cold temps shrink the fluid and suck more from the reservoir into the lines, and when it warms, the pressure builds on both sides of the system, so that the "up" and "down" pressure switches are both open and the gear won't move until I pop the bleed valve.
Nasty when the gear won't retract just after blasting off into a low overcast.
Charley Brown Legacy #299 200 hr
On Jan 25, 2013, at 7:23 AM, randy snarr wrote:
. I dont like having to open the dump valve but it is necessary once in a while especially when it is cold. The pressures on both sides of the system climb due to the engine heat and the gear sometimes will not move without dumping the pressure.
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