Went out this morning for a short flight in LNC2 N7PN.  It was shorter than I planned.  On takeoff, the gear transit light stayed on and the right main green light remained on.  I pulled the circuit breakers and did a 90-270 back to a low approach to runway 29 with the rising sun behind me.  My shadow showed all three gear extended, but I only had one light.  I pulled up to a downwind, tried the hydraulics again to no avail, pulled the breakers, opened the bypass valve, fishtailed the airplane, and the left main green light illuminated.  When I slowed to about 90 knots, the nose showed down and locked, so I landed.  Total flight time was about 6 minutes.

 

When I dismounted, I noticed hydraulic fluid on the right flap.  I crawled under the airplane and the gear door sequence valve had come apart.  The snap ring holding the mechanism in place apparently popped out or something.  I examined the valve in the right gear well and saw no obvious signs of wear, so I really don't know what happened.  I had never dismantled the valve, so I don't know if the snap ring was installed properly or not.  I hadn't paid much attention to the sequence valves other than inspecting them well at the annual condition inspection.  From now on, they'll be a specific preflight item.

Naf,

 

Nice flying.

 

This is the first time I have heard of anything like this. 

 Was the valve actuating screw recently adjusted? 

If you found enough parts, was the locking nut in place? 

If those parts are gone, is it possible that the screw/locknut backed out so that retraction would have driven the plunger too deep? 

Is there a possible side angle situation where the screw head was off center on the leg and retraction snapped (bent) the thing out of place (examine gear leg for scratch)?

 

It is hard to imagine the snap ring just giving up without some unusual force being applied....  Please keep us informed.