Aviation Accident Summaries

Aviation Accident Summary WPR13LA299

Trout Lake, WA, USA

Aircraft #1

N75542

CESSNA 172 - N

Analysis

The pilot reported that the engine was developing full power during the attempted soft-field takeoff from the 1,800-foot grass airstrip in calm wind. About halfway down the runway, the airspeed indicator only read about 40 knots. When the airplane was about two-thirds of the way down the runway, the pilot realized that he was committed to take off because insufficient runway was remaining to stop the airplane. After reaching about 45 knots, the airplane's nosewheel lifted off the runway, but it only lifted about 4 feet off the ground. About the same time, the airplane's right wing impacted two 10-foot-tall trees and a barbed wire fence. The airplane subsequently cleared a drainage ditch, the main landing gear impacted a sprinkler pipe, and the airplane skidded on all three main landing gear before coming to rest in an upright position. The airplane sustained substantial damage to the right wing and empennage. A postaccident examination of the airframe and engine revealed no anomalies that would have precluded normal operation. The airplane was within its weight and balance limits. The pilot reported that he had experience taking off and landing on short and soft fields and that, on the day before the accident, he had practiced short-field takeoffs and landings at another airport; however, he did not indicate if he had practiced soft-field takeoffs and landings at that time. The pilot should have aborted the takeoff when the airplane reached the runway's midpoint at an airspeed of only about 40 knots.

Factual Information

On June 28, 2013, about 0950 Pacific daylight time, a Cessna 172N, N75542, was substantially damaged after impacting terrain following an aborted takeoff from the Trout Lake Airport (66WA), Trout Lake, Washington. The certified private pilot and his three passengers were not injured. Visual meteorological conditions existed for the planned local flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight was originating at the time of the accident. In a written statement submitted to the National Transportation Safety Board investigator-in-charge, the pilot reported that after lining up on the 1800-foot long grass airstrip he advanced the throttle to full power with the brakes applied, 10 degrees of flaps, observed about 2,600 engine revolutions per minute, and released the brakes. The pilot stated that from the start he had the control wheel completely extended according to the procedure for soft-field takeoffs. The pilot further reported that about halfway down the runway he noticed that the airspeed indicator had only moved off the peg and just above the 40 knot mark. The pilot stated that about 60 percent of the way down the runway he realized that he was committed [to take off], as there was not enough runway to stop. The pilot reported that when he was at about 45 knots he pulled the nose off the runway, but there was only enough airspeed to lift the airplane about 4 feet off of the ground. The pilot revealed that he thought the airplane's elevator subsequently struck a barbed wire fence, just as the right wing impacted a couple of 10-foot high trees. The airplane then flew over a drainage ditch, followed by the main landing gear colliding with and severing a sprinkler pipe. The pilot added that the airplane then skidded on all three wheels before coming to rest upright about 30 feet past the sprinkler pipe. The pilot stated that because he could not attain adequate airspeed, he questioned whether something mechanical may have been wrong with the engine. The pilot reported that at the time of the accident the wind was calm and that the airplane was within its weight and balance limits. The pilot added that he had experience with soft and short fields, and that on the day prior to the accident he made 4 or 5 short-field takeoffs and landings at another airport in preparation for the next day's flight at the grass airstrip, 66WA; he made no reference to having practiced soft-field takeoffs and landings that day. The pilot added that in the future he would establish minimums for short-field operations, and not use a soft-field operations. Under the supervision of a Federal Aviation Administration (FAA) airworthiness inspector, a postaccident examination of the engine was performed by a certified FAA airframe and power plant mechanic. The mechanic reported that the initial visual inspection of the engine revealed no abnormalities. The engine compartment was clean, with no stains of oil or fuel noted. The oil level was 7 quarts, and the oil was clean. Engine cylinders 1, 2, 3, and 4 spark plugs were clean and gapped properly. Cylinder compression was tested cold, with the following noted: No. 1 - 79/80; No. 2 - 77/80; No. 3 - 78/80; No. 4 - 80/80. The throttle and mixture control cables were free and clear and observed in proper working order. The fuel valve rotated properly. The gascolator screen was clear and clean, with approximately 1 cup of fuel captured; no contaminants were observed. The airbox was clean. The carburetor, an AVSTAR MA 4-5, serial number AV95059, was removed and inspected. The carburetor accelerator pump worked properly, the carburetor bowl was clean, the floats were intact with no leakage, the springs were all in working order, the jets were clean, and approximately 1 cup of fuel was captured; no contaminants were observed. The fuel color was noted as blue. There were no known defects with either the left or right magnetos. The engine crankshaft was observed to rotate freely, with possible damage to thrust bearing, as front and back play was beyond limits. The FAA inspector reported that the engine appeared to have been well maintained, and despite the accident, was in good condition. The inspector further stated that he found no anomalies during the inspection that would indicate that the engine would not have been developing full power at the time of the accident.

Probable Cause and Findings

The pilot's failure to maintain clearance from trees during takeoff from a soft field and to abort the landing when the airplane reached the runway’s midpoint at a low airspeed.

 

Source: NTSB Aviation Accident Database

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