Aviation Accident Summaries

Aviation Accident Summary WPR20LA128

Billings, MT, USA

Aircraft #1

N926K

Piper PA31T

Analysis

Air traffic control communications revealed that the pilot requested to take off from the departure runway so that he could perform traffic pattern work and return for a landing on the left adjacent runway. Shortly after takeoff and while departing to the west, the pilot was instructed twice to enter the left traffic pattern, with no response. Radar data showed the airplane departing the runway and remaining on runway centerline heading for the length of the flight. The airplane climbed to about 100 ft above ground level and the airplane’s groundspeed increased to 81 knots soon after departure then decreased to 70 knots before dropping off radar. Witnesses reported seeing the airplane depart the airport at a low climb rate and slow airspeed. Shortly after, the airplane flew out of view and a column of smoke was seen on the horizon. Accident site documentation identified symmetrical propeller strikes on the ground consistent with the airplane impacting the ground in a shallow, nose-up, wings level attitude. Examination of the airframe and both engines did not reveal any evidence of a preaccident mechanical failure or malfunction that would have precluded normal performance to allow for sufficient airspeed and climb rate after takeoff. Both the engines exhibited damage signatures consistent with the engines producing symmetrical power at impact. The pilot’s most recent flight in the accident airplane was 2 months before the accident. The pilot was reported to have problems with understanding the accident airplane’s avionics system; however, it is unknown if he was having these problems during the accident flight. Review of the pilot’s medical history revealed no significant medical concerns or conditions that could pose a hazard to flight.

Factual Information

HISTORY OF FLIGHTOn April 20, 2020, about 0950 mountain daylight time, a Piper PA-31T1 airplane, N926K, was destroyed when it was involved in an accident about 1 1/2 miles west of Billings Logan International Airport (BIL), Billings, Montana. The airline transport pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 local flight. According to air traffic control information, the pilot requested to taxi to runway 28L for takeoff, perform pattern work at BIL, and return to land on runway 28R. After the pilot held short of runway 28L, the controller cleared the pilot for takeoff with instructions to extend the upwind leg. Shortly after takeoff and while departing to the west, the pilot was instructed twice to enter the left traffic pattern for runway 28R, with no response. A subsequent attempt was made to establish communication, with no response. Video from a security camera shows a column of smoke west of the airport about 1.5 minutes after the airplane departed. Radar data showed the airplane departing runway 28L and remaining on runway centerline heading for the length of the flight. The airplane’s altitude climbed to about 100 ft above ground level and the airplane’s groundspeed increased to 81 knots soon after departure, and then decreased to 70 knots before dropping off radar near the accident site. Witnesses located near the departure end of runway 28L watched the airplane through a window. The airplane was lower than normal with its gear not retracted as it neared the end of the runway. All the witnesses moved outside to watch as the airplane flew away from their location. One of the witnesses stated that the airplane had a “slow descent trajectory and a slight-nose up attitude.” The airplane passed over a hill and out of view. None of the witness reportedly saw the accident sequence but saw the column of smoke rising from the accident site. Another witness who was sitting in his vehicle near the accident site saw the airplane pass about 250 ft in front of his position. He reported the airplane’s wings were level, and the landing gear was up when it struck the ground. He lost sight of the airplane as it flew into a nearby coulee. PERSONNEL INFORMATIONThe 64-year-old pilot held an airline transport pilot certificate with rating for multiengine land, single engine land and single engine sea. His most recent first-class Federal Aviation Administration (FAA) airman medical certificate was issued on dated May 22, 2019. At that time, he had reported 12,955 total hours of flight experience and 65 hours in last 6 months. The pilot’s logbooks were not located during the investigation. The pilot completed a flight review in the accident airplane in December 2019. According to the flight instructor who conducted the flight review, the pilot seemed “unnerved” by the airplane’s avionics. The flight instructor reported that the pilot was a good pilot but did have to spend some extra time with him with the avionics. Additional training specific to the accident airplane was completed on January 25, 2020. The pilot had flown the airplane eight times in the last three weeks before it was put into scheduled maintenance. The pilot’s last flight before maintenance was on February 13, 2020. While the airplane was down for maintenance, the pilot performed 4 hours of aircraft familiarization in the accident airplane with one of the fixed based operator’s (FBO) employees. This training included weight and balance review, sample loading, and flight log and aircraft time verification in the avionics system. Additional to the training, the pilot had an hour of avionics run-up checks by himself. The airplane had been returned to service on February 29, 2020. AIRCRAFT INFORMATIONThe airplane was manufactured in 1980. The airplane was a multiengine, all-metal, low-wing, with a retractable tricycle landing gear configuration. It was equipped with two 550-shaft-horsepower Pratt and Whitney turbine engines. The last inspection was completed on November 25, 2019, at an airplane total time of 4,696 hours of operation. AIRPORT INFORMATIONThe airplane was manufactured in 1980. The airplane was a multiengine, all-metal, low-wing, with a retractable tricycle landing gear configuration. It was equipped with two 550-shaft-horsepower Pratt and Whitney turbine engines. The last inspection was completed on November 25, 2019, at an airplane total time of 4,696 hours of operation. WRECKAGE AND IMPACT INFORMATIONGround scars found near the top of a coulee consisted of the airplane’s fuselage impact mark and symmetrical propeller strikes consistent with the airplane impacting the ground in a shallow, nose-up, wings-level attitude. The airplane continued about 410 ft over the coulee and about 75 ft down the side before impacting the terrain where a postimpact fire ensued. All major structural components of the airplane were located within the debris field. Figure 1-Accident site, initial ground impact marks. The FAA and a representative from Piper Aircraft Company responded to the accident site, and onsite photographic documentation was accomplished. An airframe examination was performed at the accident site and the wreckage was recovered to a secured facility. TESTS AND RESEARCHThe engines were shipped to the manufacturer where examinations were conducted on both engines with the FAA conducting the federal oversight. According to the manufacturer, the examination did not reveal any evidence of any pre-impact mechanical anomalies that would have precluded normal operation. The rotational scoring on the compressor and power turbines of both engines are consistent with the engines producing symmetrical power at the time of the impact.

Probable Cause and Findings

The degraded airplane performance after takeoff for reasons that could not be determined from available evidence.

 

Source: NTSB Aviation Accident Database

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