Dom,

My 360 requires a strut force somewhere south of 65 lbs to lock the gear in flight.  The strut when new at ~100 lbs has a huge margin.  I base my replacement interval on actual strut performance in-flight.  I look for the maximum airspeed at which the gear will lock.  I start at 120 KIAS and free-fall the gear.  New gas struts will lock the nose gear even at this much elevated speed.  If it does not lock, I start slowing until I get a green light.  During this test the gear has already lost its momentum from the free fall and it is just the  gasstrut pushing the gear forward into the airstream.  Once the maximum locking speed (without the aide of a free fall) drops below 100 KIAS I replace the strut.  They have been lasting about seven years.   Note that undue friction in the bearings or linkages can reduce your margins during the free fall.  So even if the strut is replaced more frequently, an inflight test is the only way to know the actual functional performance of the system.

In-flight testing of the emergency extension is a critical maintenance item.  Throughout the years the Lancair fleet has suffered a number of nose gear collapses  (following emergency extensions) as a result of weak gas struts that were not being properly checked.

Note that undue friction in the bearings or linkages can reduce your margins during the free fall.  In an actual emergency extension one should slow down at 80 to reduce the air loads.

For more nose gear maintenance items:

http://www.lancairowners.com/nosegearmaintenance/

Chris Zavatson

N91CZ

360std