NTSB Factual Report

On September 18, 2004, at 0715 mountain standard time, an experimental category Wolf Glassair IIS, N110UX, collided with terrain immediately after takeoff from Falcon Field, Mesa, Arizona. The owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot and a mechanic/passenger were fatally injured; the airplane was destroyed. Visual meteorological conditions prevailed, and a flight plan had not been filed.

Witnesses reported to the National Transportation Safety Board investigator that the airplane took off from runway 04R, was airborne by mid field, and climbed to about 100 feet. After the initial climb it did not appear to be climbing or accelerating normally. Some witnesses reported that the engine did not sound good and described engine noise fluctuations. The airplane then rolled to the left and impacted the ground inverted.

Examination of the Falcon Field tower radio communications audio tape recording revealed that the pilot broadcasted "Falcon tower, 110UX, like to return to land, emergency" about 1 minute 40 seconds after he was cleared for takeoff. The tower responded with a clearance to land on any runway. Twenty seconds later the tower broadcasted that an airplane had just crash off the end of the runway.

Examination of the airplane's maintenance records revealed that the airplane had undergone its annual inspection at Phoenix Composites, a local fixed base operator (FBO), and the flight was part of a post maintenance check. The work done on the airplane included replacement of the engine driven fuel pump, replacement of the fuel filter, and an overhaul of the supercharger. The general manager said that the pilot and the mechanic had performed an engine ground run the previous evening.

The engine and airframe were examined at Air Transport, Phoenix, Arizona. The Textron Lycoming technical representative and Federal Aviation Administration (FAA) inspectors performed the examination under the direct supervision of the Safety Board investigator-in-charge (IIC).

The airframe had been extensively thermally damaged in the post impact fire and consisted of mostly charred and collapsed fiberglass cloth. The aileron flight control tubes were traced from the cockpit control stick and found connected to both left and right aileron control surfaces. The right aileron control tube was fractured at the right wing root area. Rudder cables were traced from the cockpit to the rudder bell crank assembly. The elevator push tubes were traced from the aft bulkhead to the elevator assembly. The right main landing gear actuator arm was retracted and the left main landing gear inboard gear door was crushed inward.

The engine was hung by a hoist for examination. The left side ignition mount pad had a Slick 4271 magneto mounted to it. The magneto was severely thermally damaged and untestable. The right side ignition mount pad had an Electroair direct ignition rotor mounted to it, which when removed from the engine mount pad could be rotated by hand. The associated ignition box was thermally destroyed and untestable. Both sets of ignition harnesses were thermally destroyed. The spark plugs were oily black in color and exhibited no mechanical damage. Thumb compression was achieved on all four cylinders; all valves lifted an appropriate amount and in firing order sequence. The engine driven fuel pump was thermally destroyed and untestable. The Aero Solutions supercharger was displaced from its mountings and subjected to thermal effects; the impeller exhibited no leading edge damage and could not be hand rotated. The supercharger overpressure valve was thermally destroyed.

The electric fuel boost pump and fuel filter assembly was removed from its location in the wing and disassembled. The pump was clear of debris and could be hand rotated. The fuel filter was clear of debris.

The fuel selector was extensively thermally damaged. The selector valve shaft was loose in the valve housing and the fuel selector position could not be determined.

The Hartzell constant speed propeller was displaced from the crankshaft flange. The propeller blades remained attached to the propeller hub. Both blades displayed leading edge polishing, torsional twisting, and chordwise striations across the cambered surface.

NTSB Probable Cause

a partial loss of power for undetermined reasons, and, the failure of the pilot to maintain an adequate airspeed while maneuvering for a forced landing that resulted in a stall and a collision with terrain.