I have the dubitable distinction of one gear-up landing in my logbook, intentional, caused by hung mains, with perfect nose gear cycling. I even have a video of it at Pax River. It was a T-39 modified for radar testing, about 1989, and I believe the unusual stresses of the long abnormal nose cone damaged the core box structure around the landing gear. The plane never flew again but sits in the museum at Pax.
Lesson learned, among others, was to land with all three gear up. The other choice was nose gear down alone, a very unstable condition. what I discovered as the test pilot in this realm of flight, which is never tested until it happens, is ground effect on pitch control. When the downwash from the wing gets close to the runway, it changes the angle of attack on
the horizontal stabilizer, increasing lift back there, and pitching the nose down. The pilot reacts by pulling and pitching up. As soon as the wing leaves ground effect, there is overcompensation in pitch up, so you then push the nose down again. This generates a classic "pilot induced oscillation" (PIO) The pilot is exactly 90 degrees out of phase with the pitch control and it's an undamped oscillation. This is not a good thing to misunderstand, close to the ground, on your first intentional gear up landing. I cannot say if this is a potential problem in other airplanes. I suspect a low wing and low horizontal tail might aggravate, while a high wing or t-tail might lessen the effects.
A review of mishaps indicates lots of loss of control in this scenario: dragging wings, pitch overs, ground loops, departing the runway. I Found, on the T-39, just hold the attitude and let the plane settle gently to a flare in ground effect. The roll was
stabilized by the symmetry of the inboard flaps and I had good rudder control to get back to centerline on the runway when it began to drift off to the right. I realized that I might stop at the runway intersection, but coasted on past it, to a stop about 2/3 down the runway. Military pilots dread a crash at the runway intersection, making you famous with your wingmen (ahh.., now wingpersons), for closing the whole field! I noticed it took a lot of power to taxi thereafter.
Thanks for the IV procedure and review of the nose gear gas piston. I have heard many replace this at the annual condition inspection, but it's not easy, but then....
Gear up belly landing is better than one main down. 2 mains down is better than belly, just hold the nose off as long as you can.
Humorous note: my copilot 'Smiley' (chief test pilot/instructor at TPS) was in his first flight in this airplane. He called "abeam,
gear, three UP and locked, full stop", opposite the standard Naval Air Station call, at the abeam. Since we troubleshoot and burned down to min fuel for an hour, they got everybody on the phone, entire chain of command, maint, contractors, etc, and I began to wonder if you can get too much helpful advice. One skipper said just keep pulling the emergency gear cable until something breaks, but that would keep the nose gear down alone, a worse scenario.
"Smiley" later made Admiral so this adventure was not career damaging.
And a flight Doc was flying the plane, go figure...
Safe 2014 !
"Doc" Bill Miller
FAIL SAFE NOSE GEAR EXTENSION
the check that every Lancair 4 should make in the air.
The Lancair IV series of airplanes have a "fail safe" nose gear extension system.
if the gas piston is in good condition the nose gear will extend and lock. Cost $65.00
$20,000 PART
that is the likely cost of a new propeller and engine tear down and reinstall.. YUCK
HOW TO CHECK
IN FLIGHT
slow to 120 knots
1. Raise the gear
2. pull the pump breaker
3. cycle the flaps til no movement
4. put the gear switch in the down position
IF YOU GET a GREEN LIGHT ON THE NOSE GEAR
Then you system is working as it should and you will have a nose gear even
if you have a total hydraulic failure or broken hydraulic line
TESTING ON THE
GROUND
--no positive
will only tell you if the system is not working.
you need the actual conditions of air load to be confident that the system will work under air load
LANDING GEAR UP IS A MISTAKE
A. yea, i forgot--well, we all fear that
BUT, INDICATING ONE OR TWO GREEN
Land with what you got; you will have considerable control; rudder, aileron, pitch
gear up landing is scary' NO CONTROL
there is a video of a lancair landing gear up... on purpose, so to speak
SCARY- wing tip grabs, plane spins one way; Plane spins the other way
and goodby prop and engine.
AND
as it gets harder and more expensive to
insure Lancairs, it may well be that you are going to pay out our your pocket
the repair cost.
like i say, the $65.00 part that could cost you $20,000
RECENTLY
i posted a video of a Cessna 210 landing with the nose gear only. a beauty to see
peter
I THANK CHARLIE KOHLER FOR THIS INFORMATION, HE, ME TAUGHT.
THANK YOU CHARLIE