Carl wrote:

 

Today on takeoff from Leesburg Fl on a trip back to Ann Arbor MI the tower controller informed me that one of my landing gear was not retracted. Checked the indicator lights and sure enough the nose gear light was indicating down and locked- but the mains had retracted normally. I cycled the gear down at about 150 kts (3 green), then back up as I climbed out. Still nose gear down and locked…  Slowed to 125, my usual gear down speed, cycled the gear down, 3 green. Retracted gear, all three came up as usual.

 

Anyone had a problem like this before? I checked over the gear after landing and everything looks normal. Plan to put it on jacks and swing the gear before flying again but any ideas on this one would be appreciated.

 

We replaced the gas strut at annual in October, simply because it had been in use for about 10 years. We also replaced the hydraulic cylinder end and did the over center link mod per service bulletin SB074-0111. Did gear swing after that work, all fine. Have done about 15 landings since the October annual.

 

Carl Loomis

 

Carl,

 

I have not heard of this occurrence before, but it sounds like either a restricted/galled nose actuator or significant friction/binding in the nose gear retract mechanism. Bending of the linkage/actuator rod/etc is a classic cause of this, but is not common at all within the IV-IV/P fleet. In any case, this is not something to mess around with—if any of these things are the cause, a failure to extend is as likely as a failure to retract! By the way, increased airspeed will slow/can limit the extension of your gear, especially emergency extension, but not retraction. Ditto for a defective gas spring/air strut.

 

If it were mine, I’d put the plane on jacks, disconnect the gas spring and the actuator cylinder and check the hinges/folding links for binding. You can also raise/lower the gear while on jacks and with the nose gear actuator disconnected, but for a completely valid check, I’d then remove the actuator and inspect the inside carefully after the functional test. I’ll send you Chris Zavatson’s excellent article about disassembling/servicing the actuator by separate email.

 

I can’t think of any other possibilities, given that it’s worked before, and did so again after three tries… During normal operation, my nose gear always extends and retracts first, with the mains being slower to both extend fully and to retract fully.

Bob