Aviation Accident Summaries

Aviation Accident Summary ANC98LA143

HOMER, AK, USA

Aircraft #1

N4072A

Piper PA-31-350

Analysis

The pilot departed from an intersection 2,100 feet from the approach end of the 6,700 feet long runway. Immediately after takeoff the right engine failed. The pilot told the NTSB investigator-in-charge that he feathered the right propeller, and began a wide right turn away from terrain in an attempt to return to the airport. He stated the airspeed did not reach 90 knots, the airspeed and altitude slowly decayed, and the airplane was ditched into smooth water. After recovery, the cowl flaps were found in the 50% open position. No anomalies were found with the fuel system. The airplane departed with full fuel tanks, at a takeoff weight estimated at 6,606 pounds. The right engine was disassembled and no mechanical anomalies were noted. The best single engine rate of climb airspeed is 106 knots, based on cowl flaps closed, and a five degree bank into the operating engine.

Factual Information

On September 7, 1998, at 1513 Alaska daylight time, a Piper PA-31-350 airplane, N4072A, sustained substantial damage during a forced ditching in Kachemak Bay, five miles east of Homer, Alaska, after takeoff from runway 03 at the Homer Airport. The solo private pilot was not injured. The flight was operated under 14 CFR Part 91 as a business flight to Anchorage, Alaska. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The pilot transmitted to the Homer FAA Flight Service Station that one engine had failed during takeoff, and that he was ditching. He told the NTSB investigator-in-charge during a telephone interview on September 9, that the right engine failed after takeoff about 150 feet above the ground, as the landing gear was retracting. The flaps were retracted, and he feathered the right propeller. During this interview, the pilot said the airspeed never got above 90 knots. According to the pilot, the best single engine rate of climb airspeed for the PA-31 is approximately 106 knots. In an interview with the IIC on September 8, the pilot's son said his father told him that the airspeed never reached 90 knots, and that the airplane kept losing altitude. The pilot wrote in his NTSB Pilot / Operator report on September 12, that the highest speed attained was 100 knots. He said that the airspeed decayed as he tried to maintain altitude. He attempted a wide 180 degree right turn, away from steep terrain and over the ocean, to return to the airport. At 80 to 85 knots, the stall warning activated, and the airplane settled into smooth water. The pilot escaped without a personal flotation device and the airplane sank within one minute. The pilot was rescued 47 minutes later. A pilot who lives about 1 1/2 miles beyond the departure end of runway 03 told the NTSB IIC that he saw the airplane fly past his house in a nose high attitude, very low to the water. He described the left engine operating at high speed, the landing gear up, and the flaps up. He could not see the right propeller. This witness stated that his house is about 200 feet above sea level, and the airplane was below his house. The maximum allowable takeoff weight was 7,368 pounds. The weight at takeoff was calculated to be 6,606 pounds. This was based on the following: Basic Empty Weight 4,300 pounds Pilot 198 pounds Freight 800 pounds Fuel (full) 1,308 pounds Total 6,606 pounds After recovery, the airplane was observed by an FAA inspector to be configured as follows: Flaps UP Cowl Flaps Both - 50% Landing Gear UP Right Prop FEATHERED Left Prop HIGH RPM Right Mixture CUTOFF Left Mixture FULL RICH Boost Pumps Both ON Throttles Both Full Forward Fuel Selectors Both MAIN The PA-31-350 SINGLE ENGINE CLIMB chart, shows that at the weight, temperature, and pressure for the day, the best expected climb rate, given this configuration, with cowl flaps closed, 106 knots, and 5 degrees of bank into the left engine, would be 280 feet per minute. The emergency procedures chapter of the PA-31-350 Pilot operating Handbook states under ENGINE FAILURE DURING CLIMB: "This aircraft has a single engine Best Rate of Climb Speed of 106 KIAS." This section also states that with cowl flaps open "...climb rate will be reduced by approximately 50 FPM," and "WARNING Negative climb performance may result from an engine failure occurring after lift off and before ... a speed of 106 knots has been attained." The pilot departed runway 03 from the intersection of taxiway "A." This intersection is 2,100 feet from the approach end of the 6,700 feet long runway, leaving 4,600 feet remaining. The right engine was disassembled at Alaskan Aircraft Engines in Anchorage, with the FAA coordinator and NTSB IIC present, on September 28. No mechanical anomalies were noted.

Probable Cause and Findings

A total loss of power in the right engine for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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