N4077W

HISTORY OF FLIGHTOn June 3, 2023, about 0816 central daylight time, a Piper PA-31-325, N4077W, was destroyed when it was involved in an accident near Tupelo Regional Airport (TUP), Tupelo, Mississippi. The pilot and pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

A witness who spoke to the pilot said the pilot and pilot-rated passenger were departing on a currency flight. Review of recorded communication between the pilot and the Tupelo Air Traffic Control Tower controller, revealed that at 0806:49, the accident pilot transmitted to the ground controller and asked for their instrument flight rules clearance to Tupelo. The ground controller provided the pilot the clearance, to which the pilot read back and subsequently asked for and received clearance to taxi to runway 36. At 0813:58 the accident pilot transmitted on the tower frequency and requested clearance for takeoff on runway 36. The controller cleared the pilot for takeoff on runway 36, and to proceed on course. At 0815:46 the accident pilot transmitted on tower frequency the airplane’s call sign, however, when the controller responded, no further communication from the accident pilot was heard. At 0815:56 the controller queried the accident pilot and asked if they were experiencing any difficulties, with no reply.

A performance study was conducted using ADS-B data from a publicly-available, third party service, as FAA ADS-B data was unavailable. The data showed that the pilot departed runway 36 and initiated a right climbing turn at 0810:53 to about 250 ft above ground level (agl) and a maximum ground speed of 102 knots (kts). As the airplane continued the right turn, its speed slowed to below 90 kts calibrated airspeed. The final turn tightened from an 830-ft radius turn at 93 kts true airspeed to a 560-ft radius turn at 81 kts true airspeed. The calculated turn radii and airspeeds correlated to a bank angle of 42° and load factor of 1.36g, which increased to a 46° bank with a load factor of 1.44g. The airplane’s published calibrated stall speeds in a wings-level attitude with flaps extended 15° and landing gear extended were 66 kts at 6,500 lbs and 56 kts at 4,750 lbs.

Figure 1: ADS-B Data Plots for the accident flight.

Airport and private security video of the airplane at the time of the accident were obtained. The cameras observed the departure and impact sequence. On departure the airplane is shown departing with the landing gear retracted once airborne. The airplane maintained runway heading with wings level for approximately 18 seconds before beginning a gradually increasing right turn to what appears to be the downwind pattern leg, then continued into a higher-rate turn and bank angle until the right wing appears to stall and the left wing rolls over the top of the airplane until the nose pointed downward before impacting the ground and exploding.

An NTSB sound spectrum study was performed to estimate the speed of the airplane’s engines based on available sound streams recorded by two cameras installed on airport buildings. The spectrum of the recorded sound showed that at least one of the airplane’s engines was operating at the speed of 2,550 ±110 rpm when the airplane was flying along the runway and when it was in the right turn that ended in ground impact. It could not be determined whether the recorded sound signals were generated by one or two engines because two engines operating at the same speed generate sound spectral peaks that are identical to those generated by a single engine at that speed. PERSONNEL INFORMATIONThe pilot’s logbooks showed a total time of 3,619.8 hours with 14.4 hours in the previous 90 days, 11.7 hours of which was in the accident airplane. The pilot’s most recent flight review and instrument proficiency check was completed on December 18, 2022, in the accident airplane. The pilot had a commercial pilot certificate with airplane single-engine land, multi-engine land, instrument airplane, and glider ratings.

The pilot-rated passenger’s logbook could not be located, but the private pilot reported on his most recent FAA medical application, dated December, 2021, 200 total hours of flight experience with 74 hours in the previous six months. The pilot-rated passenger was rated in single engine land and sea but did not have a multi engine rating. WRECKAGE AND IMPACT INFORMATIONThe ailerons remained partially attached to each wing by their hinges and the bellcrank remained attached to its mount. The aileron and balance cables remained attached to the bellcrank arms, and the stops were intact and unremarkable. During the examination of the recovered wreckage, the right wing aileron balance cable was found separated from the end terminal near one of the fuselage pulley brackets. The cable and terminal end were sent to the NTSB Materials Laboratory for further examination. Examination of the separated cable revealed multiple grinding and cutting marks in multiple regions. One region exhibited a U-shaped channel cut with grinding marks, metal burrs along one edge, and several cut wires. The cable assembly length was approximately 142 inches, which was between 30 and 36 inches short of the nominal assembly length, according the manufacturer’s assembly drawing. The features and measurements were consistent with the cable having been cut. The end terminal did not have any apparent cable fragments retained in the socket.

Both flap jackscrews were measured and corresponded to a flap setting of 15°. The rudder remained attached by its hinges to the vertical stabilizer and the rudder trim tab remained attached to the rudder. The rudder trim jackscrew corresponded to a slightly nose right setting. The elevator remained attached to the horizontal stabilizer and the elevator trim tab remained attached to the elevator. The elevator trim jackscrew corresponded to a partial aircraft nose up trim setting.

Examination of the engines did not reveal any preimpact mechanical anomalies. Many of the engine components were fire damaged. Oil was present in the crankcases and both engines could be rotated by hand using the propeller. Examination with a lighted borescope did not reveal any catastrophic internal failures. Both engines’ electrical systems and magnetos were fire damaged and could not be tested. Neither of the propellers were feathered, and all propeller blades exhibited signatures consistent with rotational energy at the time of impact. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilots was performed by the Mississippi –State Medical Examiner, Pearl, Mississippi. The findings listed the cause of death as multiple blunt force injuries and the manner of death as an accident. No significant natural disease was identified.

Toxicology testing performed by the FAA Forensic Sciences Laboratory detected ethanol at 0.033 g/hg in liver tissue, 0.024 g/hg in lung tissue, 0.036 g/hg in kidney tissue, 0.029 g/hg in spleen tissue and 0.14 g/hg in muscle tissue. (In tissue, concentrations in g/hg are approximately equivalent to concentrations in g/dL.) N-propanol was detected in liver, lung, kidney, spleen, and muscle tissues.

Toxicology of the pilot-rated passenger revealed the presence of cetirizine, an antihistamine that can have sedating or impairing effects, in muscle and liver tissue.