Aviation Accident Summaries

Aviation Accident Summary DEN01LA093

St. George, UT, USA

Aircraft #1

N27367

Piper PA-31-350

Analysis

The pilot departed on runway 16, which is located on a narrow mesa (the surrounding terrain is 300 to 350 feet below). He said that immediately after takeoff, he experienced a loss of power on the right engine. The pilot feathered the propeller on the left engine and performed a forced landing. He had raised the landing gear with runway left to land on. The FAA Advisory Circular 61-21A, Flight Training Handbook states that the landing gear should not be raised until a safe landing can no longer be made on the remaining portion of the runway. Postaccident examination of both engines revealed no mechanical anomalies which might have affected their performance. Recovery personnel reported that both propellers were "dramatically" bent in the opposite direction of rotation. Additionally they found that the right wing root fuel sump valve was installed improperly, and was impossible to sump. When they removed the valve, they found that the fuel sample was approximately 25% water. The wind, at the time of the attempted takeoff, was 130 degrees at 21 gusting to 31 knots. The direct crosswind was calculated to be 16 knots, which was within the airplane's demonstrated crosswind limit of 20 knots.

Factual Information

On April 27, 2001, at 1722 mountain daylight time, a Piper PA-31-350, N27367, was substantially damaged when it landed gear up following a loss of engine power on takeoff from St. George Municipal Airport, St. George, Utah. The airline transport pilot, the sole occupant in the airplane, was not injured. The airplane was being operated by American Aviation, Inc., Salt Lake City, Utah, under Title 14 CFR Part 135. Visual meteorological conditions prevailed for the cross-country cargo flight, which was originating at the time of the accident. A company VFR flight plan had been filed. According to the pilot's written statement, he took off on runway 16 with full power and a "strong left crosswind." After liftoff, the right engine failed. The pilot said "with the gear up the airplane would not accelerate and began to sink." He made a gear up landing, and the airplane slid to a stop approximately 100 feet off the right side of the runway. The pilot turned off all switches and evacuated the airplane through the left cockpit door. The right main wing spar was bent, the underside of the fuselage was damaged, and the propellers were damaged. A Federal Aviation Administration (FAA) Aviation Safety Inspector said that the pilot told him that he lost an engine on takeoff, and he "thought" he feathered an engine (the left engine's propeller was found feathered). Post impact examination of both engines revealed no anomalies which might have affected their performance. Recovery personnel reported that both propellers were "dramatically" bent in the opposite direction of rotation suggesting that there was power on the engines at the time of ground contact. They further stated that the right main fuel tank sump valve (in the wing root) could not be manipulated (opened) because of its orientation in its cavity. They said that during a normal preflight it could not have been sumped. When they removed the valve and sumped the tank, they got 25 percent water. The airplane's Information Manual (Navajo Chieftain) performance section indicates that the airplane's single engine climb rate (estimated weight of 6,500 pounds; inoperative engine propeller feathered) should have been 225 feet per minutes with the existing metrological conditions. The Information Manual also states that an airplane must be preflight checked before every flight. Normal preflight of the airplane includes sumping all seven fuel system sumps. The FAA Advisory Circular 61-21A, Flight Training Handbook states that "the landing gear may be raised as soon as practicable but not before reaching the point from which a safe landing can no longer be made on the remaining portion of the runway." The St. George Municipal Airport sits on a narrow mesa, which drops off 300 feet on one side and 350 feet on the other. The winds reported at the airport's automated weather observation station at 1735 were 130 degrees at 21 gusting to 31 knots. A wind components chart indicated that with a wind 30 degrees left of the runway heading, (using the maximum gusting wind) would have been 16 knots crosswind. The airplane's Information Manual indicates that the maximum demonstrated crosswind velocity was 20 knots. The airport manger said that because of the airport's geographic location, when the wind is 10 to 15 knots, it becomes progressively more turbulent with the wind "spilling" over the mesa. He said that pilots have reported very unusual turbulent wind during some crosswind operations.

Probable Cause and Findings

the pilot's failure to sump all the fuel drains during preflight and the subsequent loss of power in the right engine during takeoff, the pilot feathering the wrong engine's propeller during the forced landing, the pilot improperly raising the landing gear with usable runway in front of him, and lack of suitable terrain for the forced landing. Contributing factors were the water in the fuel, the terrain induced turbulent cross wind condition, and the mountainous/hilly terrain for the forced landing.

 

Source: NTSB Aviation Accident Database

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