NTSB Factual Report

HISTORY OF FLIGHT

On December 22, 1996, at 1044 hours Pacific standard time, a Piper PA-23-250, N2377T, en route to John Wayne airport, crashed and burned while diverting to Apple Valley airport, Lucerne, California. The aircraft was destroyed, and the certificated commercial pilot and her three passengers received fatal injuries. The aircraft was rented by the pilot from Command Aviation, Inc., for the cross-country personal flight when the accident occurred. The flight originated in Las Vegas, Nevada, on the morning of the accident. Visual meteorological conditions prevailed at the accident site and an IFR flight plan was filed.

The pilot was VFR on top at 8,500 feet msl when she advised Los Angeles ARTCC that she would be able to maintain VFR for only a few miles. She also reported that she was beginning to pickup ice. The controller suggested that she deviate to the west and she replied that she would turn to a heading of 240 degrees. At 1043, the pilot advised the controller that she was unable to maintain altitude, that she was experiencing moderate to severe turbulence, and then asked for the nearest airport. The controller replied that the nearest airport was Apple Valley on a heading of 290 degrees and 15 miles. The pilot then reported that her door had popped open. The controller then issued an amended heading of 280 degrees for the Apple Valley airport. There was no further radio contact from the pilot and radar contact was lost at 1044.

A witness reported to San Bernardino sheriff's deputies that he saw the aircraft level about 500 feet agl. He said that as he watched, the aircraft abruptly rolled to its right, pitched downward steeply, and continued in a nose down attitude until it disappeared from view. He said the aircraft exploded into a towering, red fireball on impact.

PILOT INFORMATION

The pilot received her private pilot certificate on March 7, 1991, her multiengine rating on May 7, 1992, and her instrument rating on May 13, 1993. She obtained her commercial pilot certificate on October 14, 1993, and her airplane flight instructor certificate on October 16, 1994. She received her airplane instrument instructor certificate on February 15, 1995, and her multiengine instructor certificate on July 22, 1995. Her last instrument competency check was completed on October 19, 1995.

AIRCRAFT INFORMATION

An inspection of the aircraft, engine, and propeller logbooks by an FAA airworthiness inspector did not reveal any discrepancies. The latest known aircraft weight and balance report was complied on January 10, 1996, by Western Avionics, Inc.

On October 2, 1996, a student pilot reported that while he and his instructor were preflighting the accident aircraft, he found that the stabilator was stuck in the down position. He said he was unable to identify any impingement on the controls; however, after wiggling the stabilator control surface, it finally broke loose. When he questioned the instructor, he said he was told that "it (the stabilator sticking) happens sometimes." He also said that, during the same flight, the cabin door popped open. Although the flight was continued with the door ajar, he said he did not notice any adverse flight characteristics as a result.

In an interview, the instructor for the flight in question stated that he did not recall the stabilator sticking, but did recall the door opening in flight.

The aircraft manufacturer reported that there have been no reported incidents for this model aircraft in which the stabilator stuck at any point in its range of travel.

A mechanic for the operator reported that he had repaired a broken cabin door latch spring. No aircraft logbook entry was found for that repair.

On December 17, 1996, a loose wire was found which was preventing the alternator from coming on line. The loose wire was repaired.

The pilot operating handbook (POH) emergency procedures section states that should the door open in flight, the pilot should slow the airspeed to reduce buffeting and then land at the nearest airport. The POH also states that should the pilot encounter rough air, the aircraft should be slowed to maneuvering speed or slightly less (131 knots). The pilot is directed to fly with reference to attitude and to avoid abrupt maneuvers. All seat belts and shoulder harnesses should be tightened.

On December 21, 1996, the accident pilot reported to the operator that she had experienced a battery problem. A battery was flown to Las Vegas by the operator and installed in the aircraft before the return flight.

The last recorded fuel purchase was for 26 gallons of 100LL from Signature Aviation on December 20, 1996.

METEOROLOGICAL CONDITIONS

At the time of the accident a frontal boundary of a weak cold front was passing over the area in an easterly direction. Surface winds were generally from the southwest about 40 to 45 knots and had been increasing in intensity.

Mountain wave and moderate turbulence were reported in the vicinity of Palmdale. Moderate to severe turbulence was reported in the vicinity of Palm Springs, Victorville, and Bermuda Dunes, with the conditions ranging from 7,000 to 16,000 feet msl.

Light rime icing was reported in the Palm Springs area and in the vicinity of the Paradise VORTAC between 8,000 and 10,000 feet msl.

The area forecast north of Palm Springs indicated scattered to broken clouds at 9,000 feet becoming broken at 12,000 feet msl. Cloud tops were expected to reach 30,000 feet. Widely scattered rain showers were also expected with rain turning to snow above 6,000 feet.

SIGMET Papa 12 forecasted moderate to severe turbulence below FL 200 with low level wind shear expected. SIGMET Papa 13 extended the forecast below FL 180.

WRECKAGE AND IMPACT INFORMATION

The wreckage was located about 100 feet south of Cambria Road and 1 mile east of Highway 247 in Lucerne Valley at 34 degrees 29.956 minutes north latitude and 116 degrees 55.892 minutes west longitude.

The aircraft impacted flat desert terrain. A ground scar 37 feet in width was found to contain both engines. The aircraft came to rest on a magnetic heading of 312 degrees. Soot patterns on vegetation was on a magnetic heading 064 degrees. The debris field was forward and to the right of the nose of the aircraft. Sheet metal fragments from the aircraft were found east of the main wreckage with the farthest located about 1,600 feet away.

The fuselage and cabin area exhibited impact and fire damage. The fuel selector was positioned on the left and right inboard fuel tanks. The fuel filler caps from the tanks in the main wings were found at the impact site. All flight control surfaces were located; however, due to the extent of impact damage, control continuity was not established.

The front and rear luggage doors were both located at the accident site. The forward door was examined for evidence of contact with the propeller. The striker plates on both door frames were examined for evidence of distortion. There was no evidence of blade contact on the forward door and both striker plates showed evidence of distortion.

The cabin door assembly was found at the impact site. The door and frame exhibited both impact and fire damage. The upper forward door support pin was found in the forward frame assembly. The bottom lock rod pin was found in the retracted or unlocked position. The door latch assembly had separated from the door assembly. The striker plate exhibited evidence of exposure to the postcrash fire, but was otherwise not distorted.

Both flaps were found in the retracted position. The landing gear locks were over center. The stabilator trim jack screw was found with no exposed threads. The jack screw's position, according to the manufacturer, is equivalent to 3 degrees tab up.

The engines were imbedded in the earth on a near vertical orientation to a depth approximately equal to their length. The propellers, main wings, tail assembly, and flight control surfaces were also located at the accident site.

The right engine showed evidence of impact damage and postcrash fire. Valve and gear train continuity were established through a visual inspection. The accessory section had been destroyed by impact forces and fire. The right propeller separated from the crankshaft at the crank cheek just aft of the front bearing. The separated propeller was found imbedded in the same ground scar as the engine.

The propeller flange and a portion of the crankshaft remained attached to the propeller. One blade had separated from the hub assembly, but it was found in the same ground scar. The separated blade exhibited S-bending at midspan and exhibited torsional twisting. The blade was fractured about 5 inches inboard from the tip. The separated portion of the blade was also recovered from the same ground scar. The remaining blade was bent forward about midspan, exhibited torsional twisting, and was in flat pitch.

The left engine showed evidence of impact damage and postcrash fire. Valve and gear train continuity were established through a visual inspection. The accessory section had been destroyed by impact forces and fire. The left propeller remained attached to the engine crankshaft.

The propeller flange was bent about 45 degrees to the normal plane of rotation. One blade had separated from the hub, but was found in the same ground scar. The separated blade exhibited bending and torsional twisting. The tip had separated from the blade but was also located in the same ground scar. The remaining blade was bent forward about midspan, exhibited torsional twisting, and was in flat pitch.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed by the San Bernardino County Coroner on December 31, 1996. Samples of muscle tissue were taken for toxicological examination at the Civil Aero-Medical Institute (CAMI). The results of the examination revealed the presence of ethanol and acetaldehyde in the tissue.

The Safety Board flight surgeon reviewed the results of the toxicological examination and stated that the results suggest postmortem alcohol production.

FIRE

Wreckage at the point of impact with terrain exhibited evidence of fire. Wreckage found outside the immediate impact area was neither burned nor sooted. Witnesses stated that the aircraft burst into a fireball on impact with the initial flames reaching a height of about 50 feet. The flames dissipated after about 15 seconds and a ground fire continued to burn.

TESTS AND RESEARCH

Radar data was reviewed with the aid of a computer software program. The data revealed that the aircraft beacon showed a turn to the west when Los Angeles ARTCC lost contact. The impact site is located about 1 nautical mile northwest of the last beacon return.

ADDITIONAL INFORMATION

The aircraft was recovered by personnel from National Aircraft Salvage and secured in a hangar at Brackett Field, La Verne, California. The wreckage was released to a representative of the registered owner on May 22, 1997.

NTSB Probable Cause

the pilot's failure to maintain an adequate airspeed after encountering turbulence, low level wind shear, and an open door.