Aviation Accident Summaries

Aviation Accident Summary SEA01LA116

Custer, WA, USA

Aircraft #1

N52BG

Yakovlev YAK 52

Analysis

The experimental category Yakovlev Yak-52, was destroyed after colliding with terrain while maneuvering. The first pilot, a commercial pilot/certified flight instructor who was seated in the forward seat, and the second pilot, a commercial pilot receiving instruction, were fatally injured. The accident airplane, a Yak-52, was the number two airplane in a flight of three aircraft. Shortly after takeoff, the number three airplane (Yak-18) returned to secure a fuel door that became unlatched during the initial takeoff. The pilot of the Yak-52 elected to maneuver over an area know as Cherry Point and wait for pilot of the Yak-18 to rejoin him. Approximately 10 minutes later, the pilot of the Yak-18 rejoined the Yak-52. The Yak 18 pilot stated that as he approached the area from the northwest, he observed the accident airplane maneuvering northeast of his position at an altitude of 1,500 feet mean sea level (MSL). He instructed the Yak-52 pilot to reverse his course in an effort to join him in formation flight. He reported that shortly after the pilot of the Yak-52 initiated the turn to the west (left), the airplane "...stalled and pitched nose down at about 40-60 degrees." Reportedly, the Yak-52 then rolled to the right, pitched up and oscillated around its vertical axis. Witnesses stated that the accident airplane rotated 2-3 times prior to impacting terrain. The pilot of the Yak-18 stated the accident airplane impacted terrain in a relatively level attitude with little forward motion. Post accident inspection of the airplane and associated components revealed no evidence of a preimpact mechanical malfunction or failure.

Factual Information

On June 10, 2001, about 1220 Pacific daylight time, an experimental category Yakovlev Yak-52, N52BG, was destroyed after colliding with terrain near Custer, Washington. The aircraft was owned by a private party and was being operated as a visual flight rules (VFR) cross-country flight under the provisions of Title 14, CFR Part 91. The first pilot, a commercial pilot/certified flight instructor who was seated in the forward seat, and the second pilot, a commercial pilot receiving instruction, were fatally injured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight originated from a private airstrip near Point Roberts, Washington, approximately 10 minutes prior to the accident. The pilot's planned destination was Snohomish County Paine Field, Everett, Washington. The accident airplane, a Yak-52, was the number two airplane in a flight of three aircraft that departed Point Roberts. Shortly after takeoff, the number three airplane (Yak-18) returned to Point Roberts to secure a fuel door that became unlatched during the initial takeoff. The pilot of the lead airplane (Yak-55) continued to his intended destination. The pilot of the Yak-52 elected to maneuver over an area known as Cherry Point and wait for the pilot of the Yak-18 to rejoin him and then continue to their final destination as a flight of two. Approximately 10 minutes later, the pilot of the Yak-18 rejoined the Yak-52. The Yak-18 pilot stated that as he approached the area from the northwest, he observed the accident airplane maneuvering northeast of his position at an altitude of 1,500 feet mean sea level (MSL). He instructed the Yak-52 pilot to reverse his course in an effort to join him in formation flight. He reported that shortly after the pilot of the Yak-52 initiated the turn to the west (left), the airplane "...stalled and pitched nose down at about 40-60 degrees." Reportedly, the Yak-52 then rolled to the right, pitched up and oscillated around its vertical axis. Witnesses stated that the accident airplane rotated 2-3 times prior to impacting terrain. The pilot of the Yak-18 stated the accident airplane impacted terrain in a relatively level attitude with little forward motion. Whatcom County Sheriff's Deputies reported that the airplane came to rest in an open field near Jackson Road. They reported that the airplane appeared to have impacted terrain in a nose-low attitude, and that the left wing and cockpit canopy had separated from the main structure. In a subsequent written statement, deputies reported smelling "...a very distinct odor of spilled fuel around the airplane..." On June 20, 2001, personnel from the National Transportation Safety Board and the Federal Aviation Administration examined the wreckage at the airplane owner's hangar facility near Everett, Washington. The wreckage consisted of the engine and associated engine components, the remnants of the fuselage and cockpit, both wings and respective flight control surfaces, and the separated empennage and tail control surfaces. Impact damage was noted to the frontal and accessory areas of the radial engine. The cylinders and associated overhead components were intact and observed to be in their respective locations. A number of the rear accessories, oil and pneumatic lines and ignition components sustained impact damage and were displaced from their respective mounting flanges/pads. The crankshaft flange and propeller hub assembly was intact, however, both propeller blades (wood) were sheared from the hub assembly. Propeller blade "A" was fractured at mid-span and separated from the propeller hub at the root of the blade. Propeller blade "B" also separated from the hub and fractured at mid-span. The inboard section of the propeller was not recovered. Downward and aft crushing was noted to the front and rear cockpit areas and canopy. The instrument panels and cockpit controls sustained heavy impact damage and extensive fragmentation was observed. During the examination of the cockpit, the owner of the airplane indicated that the stall warning system was inoperative and that the airplane was normally operated in this configuration. It was also noted that the cockpit instruments and switches were marked with Cyrillic lettering and no English markings or conversions were noted. Both wings were recovered from the accident site and were secured with the main wreckage. Leading edge damage and rearward crushing was noted to the inboard section of the right wing. The right wing flap and aileron sustained impact damage, but were still attached to the wing prior to recovery efforts. The main landing gear was attached to its respective attach points and was observed in the up position. The left wing separated from the fuselage at the wing root. The two sections of the left wing (inboard and outboard) sustained crushing type damage to the leading edge and trailing edge surfaces. The aileron separated from the attach points. A section of the left flap was still attached to the inboard section of the wing. The empennage separated from the main fuselage midway between the canopy and vertical stabilizer. Both elevators remained attached to the horizontal stabilizer and the rudder was attached to the vertical stabilizer. Upward crushing was noted to the lower portion of the rudder. Control continuity was established from the empennage flight control surfaces forward to the area where the tail section separated from the fuselage. Postmortem examinations of both pilots were conducted by the Whatcom County Medical Examiner's Office, Bellingham, Washington. According to the autopsy report(s), the cause of death for the two pilots was attributed to "Multiple injuries due to blunt trauma." The manner of death for both pilots was listed as accidental. The FAA Civil Aeromedical Institute (CAMI), Oklahoma City, Oklahoma, conducted toxicology testing on both pilots. All test results for the first pilot were negative. Test results for the second pilot indicted that amounts of Bupropion and Bupropion Metabolite (a prescription antidepressant) was detected in the second pilot's blood and liver (forensic toxicology report attached). According to FAA records, the first pilot held a second-class medical certificate dated June 14, 2000. Records for the second pilot indicated that he held a first-class medical certificate dated February 8, 1996. On July 7, 2001, the airplane, engine and associated components were released to the registered owner in Bellevue, Washington.

Probable Cause and Findings

The first pilot's failure to maintain aircraft control while maneuvering. Factors include an inadvertent stall.

 

Source: NTSB Aviation Accident Database

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