Per,



I think it is most likely one of the cylinder piston seals. They don¹t

always fail completely. I once had one that would leak only when the gear

was down. With the gear up the pressure did not decay and the pump did not

cycle. As soon as I put the gear down, every minute the pump would cycle

on for a second. Raise the gear and it was okay again.



I¹m not sure why it would stop after 15 minutes, but maybe it has to do

with temperature of the cylinder and seal. If you can get it to happen on

the ground, cap one cylinder off at a time until you find it. It could be

one of the door cylinders, but I think they are less likely to be leaking.

Mine door cylinders have not leaked in 1250 flight hours.



Mike Reinath

LNC2 N3602M at 1250 TT

San Jose, CA