Aviation Accident Summaries

Aviation Accident Summary WPR12FA058

Coupeville, WA, USA

Aircraft #1

N2611R

PIPER PA-28R-200

Analysis

Witnesses located adjacent to the accident site reported observing the accident airplane approaching their position at a low altitude while over water and that it appeared as if the pilot were attempting to land in an open prairie located at the top of a cliff. The witnesses stated that as the airplane moved closer, they did not hear the engine as the airplane impacted a bluff just below a ridgeline and a postimpact fire ensued. One witness stated that it appeared the propeller was windmilling before impact with terrain. First responders extinguished the fire with an unspecified amount of water from a fire truck. A postaccident examination of the airframe and engine revealed no evidence of preaccident mechanical malfunctions or failures that would have precluded normal operation. However, during the postaccident examination, evidence of water was located within the airframe fuel filter and engine fuel flow divider. Due to the damage sustained to the airframe and engine, it could not be determined if the water was introduced into the system during postaccident firefighting efforts or from another source.

Factual Information

HISTORY OF FLIGHT On December 8, 2011, about 1557 Pacific standard time, a Piper PA-28R-200, N2611R, was substantially damaged during a forced landing near Coupeville, Washington. The airplane was registered to Whidbey Island Navy Flying Club, Oak Harbor, Washington, and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot, sole occupant of the airplane, sustained fatal injuries. Visual meteorological conditions prevailed and a company flight plan was filed for the personal flight. The local flight originated from the Whidbey Island Naval Air Station (NUW), Oak Harbor, Washington, about 1500. In a written statement to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), a witness, who was a rated pilot, located adjacent to the accident site reported observing an airplane approaching their position at an altitude of about 500 to 700 feet above the water as if the pilot was attempting to land in a nearby open field at the top of a cliff. The witness stated that as the airplane moved closer, they did not hear the engine and watched the airplane impact terrain just below a ridge line of a cliff and erupt into flames. He added that the entire time he saw the airplane, the landing gear was in the extended position and the flaps appeared to be retracted. A second witness, who was sitting in a parked car adjacent to the accident site reported that the pilot appeared to be attempting to land in an open prairie, however, the airplane impacted the ground about halfway up a bluff. The witness added that the airplane appeared to remain at a constant altitude from the time they saw it until it impacted the ground. First responders to the accident reported that in order to extinguish the post-accident fire, they utilized an unspecified amount of water from fire trucks. PERSONNEL INFORMATION The pilot, age 59, held a private pilot certificate with an airplane single-engine land rating. A third-class airman medical certificate was issued on July 22, 2010, with no limitations stated. The pilot reported on his most recent medical certificate application that he had accumulated 295 total flight hours. The pilot’s logbook was not located. AIRCRAFT INFORMATION The four-seat, low-wing, retractable-gear airplane, serial number (S/N) 28R-35669, was manufactured in 1969. It was powered by a Lycoming IO-360-C1C engine, serial number L-11661-51A, rated at 200 horse power. The airplane was also equipped with a Hartzell model HC-C2YR-1BF, serial number AW2375 adjustable pitch propeller. The operator of the airplane reported that the airplane was typically parked outside on the ramp area, which was not covered. Review of the airframe and engine maintenance logbooks revealed that an annual inspection was completed on May 26, 2011, at a tachometer time of 906 hours and airframe total time of 3,869 hours. The most recent 100-hour inspection was completed on October 7, 2011, at a tachometer time of 1,099 hours, airframe total time of 4,063 hours, and engine time since major overhaul of 1,176.9 hours. METEOROLOGICAL INFORMATION Review of recorded weather information from NUW, located about 10 miles north of the accident site, revealed that at 1556, weather conditions were wind from 040 degrees at 3 knots, visibility 10 statute miles, scattered cloud layer at 2,200 feet, broken cloud layer at 4,000 feet, broken cloud layer at 25,000 feet, temperature 4 degrees Celsius, dew point -1 degree Celsius, and an altimeter setting of 30.43 inches of mercury. COMMUNICATIONS Information provided by Whidbey Island approach control revealed that the pilot initially established radio contact and reported inbound to NUW at 1,400 feet. No distress calls were received from the pilot. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the airplane impacted a hill side about 50 feet below the top of a ridge line adjacent to an open field and came to rest upright. A large area of disturbed dirt about 20 feet upslope of the main wreckage was identified as the initial impact point. Within the area of disturbed dirt, various portions of plexi glass, nose wheel landing gear, outside air temperature gauge, and engine oil dip stick were located. The main wreckage was located about 20 feet downslope of the initial impact point. All major structural components were located within about 100-feet of the main wreckage. Examination of the main wreckage revealed that the center portion of the fuselage from the base of the vertical stabilizer forward to the engine was consumed by fire. The left wing remained attached to the fuselage. Both the left flap and left aileron remained attached to the wing. The inboard portion of the left wing was consumed by fire. The right wing remained attached to the fuselage. Both the right flap and right aileron remained attached to the wing. The inboard portion of the right wing was consumed by fire. Both leading edges of the left and right wings were crushed aft throughout their span. The vertical stabilizer and rudder were intact and undamaged. The horizontal stabilator remained attached and was intact and undamaged. The nose wheel landing gear was separated from its mounts. Left and right main landing gears were observed in the extended position. Both the left and right vented fuel caps were intact and exhibited fire damage. Flight control continuity was established from the cockpit control column and rudder pedals throughout to all primary flight controls. All areas of separation within the control system were consistent with thermal damage and wreckage recovery efforts. The horizontal stabilator trim actuator was measured at 0 threads, which equates to nose down, tab up, approximately 3 degrees. Examination of the airframe fuel filter revealed that it was intact and remained attached to the engine firewall. The fuel filter bowl was removed and a liquid (tested positive with water finding paste) was observed. Examination of the recovered engine was conducted on December 10, 2011, at the facilities of AvTech Inc., Auburn, Washington, by representatives of Lycoming Engines, Piper Aircraft, and Federal Aviation Administration under the supervision of the NTSB IIC. The engine remained partially attached to the firewall via its mounts. The engine exhibited thermal and impact related damaged. All four cylinders remained attached to the engine crankcase. The vacuum pump, propeller governor, fuel pump, left and right magnetos were secure to their mounts and exhibited severe fire damage. The fuel injection servo was recovered with the separated throttle plate, which were fire damaged. The fuel injector servo brass plug was observed partially dislodged from the side of the fuel injector servo. The safety wire was intact. The fuel flow divider was found secure to its mount and was subsequently removed and disassembled. No defects were observed to the fuel flow divider. A trace of liquid, which tested positive with water finding paste, was observed on the rubber diaphragm and internal areas of the housing. The oil suction screen was removed and found to be free of debris. The oil sump was impact damaged. All accessories were removed from the accessory housing. All of the spark plugs were removed. All rocker arm covers were removed. The propeller was removed. The crankshaft propeller flange exhibited impact damage and was removed from the crankshaft to facilitate crankshaft rotation. The crankshaft was rotated by hand using a hand tool at an accessory drive pad. Rotational continuity was established throughout the engine valve train and accessory gears. Thumb compression and suction was noted on all four cylinders. The propeller assembly was intact. Both propeller blades remained attached to the propeller hub in a low pitch position. One propeller blade exhibited an approximate 5 degree aft bend throughout its span. The opposing propeller blade exhibited an approximate 5 degree forward bend about 10 inches inboard from the blade tip. The fuel injector servo was sent to the NTSB Materials Laboratory in Washington, DC for further examination. MEDICAL AND PATHOLOGICAL INFORMATION The Island County Coroner conducted an autopsy on the pilot on December 9, 2011. The medical examiner determined that the cause of death was “...Blunt force injuries” The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report, carbon monoxide, cyanide, volatiles, and drugs were tested, and had negative results. TESTS AND RESEARCH The fuel injector servo was examined at the NTSB Materials Laboratory. As-received, the hex plug was found loose and could be manually rotated and wiggled within the regulator cover plate, consistent with significant distortion within the threaded hole in the regulator cover plate. The safety wires were threaded through each of the mounting screws on the regulator cover plate and through the hex plug. The safety wires attached to the hex plug were cut during the laboratory examination and the hex plug was manually unscrewed from the regulator cover plate. Examination of the threaded hex plug hole in the regulator cover plate using a 5X to 50 X stereo zoom optical microscope revealed that the regulator plate was heat-damaged in a manner that substantially distorted the plate at the hex plug threads. The entire regulator cover plate was heat-damaged to an extent that the aluminum core fused and flowed away leaving largely a wrinkled and sagged hollow shell comprised of oxidized aluminum and some re-solidified aluminum under the oxide.

Probable Cause and Findings

The total loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal evidence of preaccident mechanical malfunctions or failures that would have precluded normal operation.

 

Source: NTSB Aviation Accident Database

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