It hit a "mountain of turbulence" and the tail "dug in"? What universe
did that happen in? Aft CG would exacerbate any tendency to a pitch
overshoot after a tab failure, but I can't see how any amount of
turbulence could produce a 10G pitchup without a coincidental tab
failure, unless the plane was totally unstable and Leeward was crazy to
be flying it. The pitch-up would reduce tab loads, not increase them.
Actually, the tab seems to have had two or three failures: possibly an
actuator first, then a hinge, and then the tab itself, mid-span. Maybe a
hinge was the first to go. NTSB metallurgists should be able to identify
pre-existing fatigue cracking, if there was any.

People are going to have axes to grind here, and blaming the pilot is
always a good strategy. Funny that the Hannah/Voodoo precedent is not
mentioned in this explanation. Another turbulence-mountain?

Peter Garrison

So here is the scoop I got over the weekend. Turns out one of the mechanics at the airport was on the ground team for one of the unlimited racers and had the spot in the pits right next to the lost plane. The ground team had a real time data feed from the airplane.

Looks like the plane had a high speed flutter on the port elevator trim tab. The pilot reported a vibration.

The trim tab came off in flight which caused the entire tail group to twist. There are trim tabs on both sides and the asymmetry caused a huge over load. Also high power settings require a lot of nose down trim to stay level, the loss of the trim tab could not be overcome by the pilot. The twist in the tail group made the tendency to nose up even greater and caused damage to the internal structure in the tail  looking at the pictures you will see the tail wheel is down and the gear doors are gone stuff was coming apart in there.

The twist and the loss of trim caused a near instantaneous 11G pull up  this probably incapacitated the 73 year old pilot and may even! ; have broken the mounts on the pilot seat. Note you cannot see him in the cockpit. The 11G pull also caused a brief loss of engine power from low fuel pressure the pump could not overcome 11G.

After the 11G pull up the airplane unloaded in steep climb  with the G off the engine regained power.

Without the pilot to overcome it the airplane torque rolled causing a split S into the ground.
The data showed that the airplane was pulling 105 inches on manifold pressure on impact. The "normal" race boost would be 60 to 70. So the airplane was going just under 500MPH when it hit so no fire just total disintegration


Mike Ethridge


As I understand it there was only one trim tab. The other had been removed.
Therefor there would be no torque on the elevator tube due to that.
Only due to the stick angle.


Paul Lamar

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