Surveillance footage and federal tracking data detail how a Cessna approached a hovering state police helicopter after radio contact between the crews.
CARLISLE, Pa. — Federal investigators found no evidence of a pre-impact mechanical failure in either aircraft involved in an Aug. 19 collision at Carlisle Airport that killed a Cessna pilot and seriously injured two Pennsylvania State Police aviators, according to a newly released preliminary report.
The National Transportation Safety Board report provides the clearest official timeline yet of the collision between a Cessna 150H and a Pennsylvania State Police Bell 407 helicopter. Investigators used flight-tracking information, interviews and footage from three airport security cameras to reconstruct the aircrafts’ movements. The report does not identify a probable cause or assign responsibility, and its findings remain preliminary while investigators continue examining wreckage and recorded data.
The NTSB placed the collision at 6:52 p.m. Aug. 19. The state police had initially reported an approximate time of 6:58 p.m. The helicopter crew had departed Capital City Airport near Harrisburg and traveled about 15 nautical miles to Carlisle Airport for flight instruction exercises. According to federal tracking data, the helicopter made a straight-in approach to Runway 28, crossed the runway threshold at about 50 feet and descended into a hover taxi. It moved about 1,800 feet along the 4,008-foot runway before leaving the paved surface to the north over a grassy field.
The Cessna was approaching the same runway as the helicopter. Investigators said the airplane crossed northeast of the airport and made left turns into the traffic pattern for Runway 28. A witness reported hearing radio communications between the airplane pilot and helicopter crew on the airport’s Common Traffic Advisory Frequency. Carlisle does not have an operating control tower, so pilots use the shared frequency to announce their positions and intentions to other aircraft in the area.
The helicopter flight instructor told investigators that the crew first detected the Cessna through the helicopter’s traffic-alert system and then saw it on the crosswind portion of the airport traffic pattern. After the helicopter crew reported its position on final approach, Cessna pilot Paul William Sokoloski asked whether the helicopter crew wanted him to extend the downwind portion of his approach. The instructor told him to extend it, and Sokoloski acknowledged the communication and said he was second in sequence for landing, according to the preliminary report.
Flight-tracking data showed the Cessna later turning onto the base leg of the traffic pattern about 2,500 feet from the runway threshold. Its ADS-B tracking ended shortly after the turn, but airport surveillance cameras recorded the rest of the flight. The footage showed the helicopter crossing the threshold while the Cessna was still on its base leg. About 30 seconds later, the airplane crossed the threshold while the helicopter remained in the runway area.
The surveillance video showed the Cessna flying low above the runway without touching down. Investigators described its wings rocking from side to side and said the aircraft made several vertical and lateral movements. As the airplane continued down the runway, the helicopter moved north over the grass and remained pointed generally toward the departure end of Runway 28. The helicopter pilots told investigators that their position and orientation prevented them from seeing the airplane approaching from behind.
The Cessna then pitched upward and began climbing, according to the NTSB. Near the top of that climb, its right wing dropped and the airplane turned right and descended toward the northwest. Investigators said the wings then returned to level before the airplane pitched upward again and struck the rear of the hovering helicopter, contacting its tail rotor and main rotor blades. The NTSB calculated that about eight seconds passed between the helicopter leaving the paved runway surface and the collision.
The helicopter sustained substantial damage, including separation of its main rotor blades and tail boom, while the Cessna was destroyed. Investigators recovered the major sections of both aircraft and found damage patterns consistent with an in-flight collision. Their examination found no evidence of a mechanical malfunction or failure before impact that would have prevented either aircraft from operating normally. Avionics capable of storing digital information were also recovered and retained for further examination.
Weather observations cited in the federal report showed visual meteorological conditions at the time. Skies were clear, visibility was 10 miles and winds were reported at 5 knots from 270 degrees at an observation facility about 18 nautical miles from the accident site. The NTSB has not said that weather, visibility, pilot actions or any other single factor caused the crash.
Sokoloski, 57, of Hershey, was the Cessna’s sole occupant and was pronounced dead at the scene, Pennsylvania State Police said. He worked as an emergency medicine physician with Penn State Health. The helicopter was carrying Cpl. Bryce Corman and Trooper Jason Mills. The NTSB classified both helicopter crew members as seriously injured. Corman was released from Penn State Health Milton S. Hershey Medical Center the day after the crash, and state police later said Mills also had been discharged, according to WGAL.
The NTSB investigation remains open. Investigators are continuing to examine the recovered avionics, aircraft wreckage, surveillance recordings and other evidence before determining a probable cause. The preliminary report states that its information is subject to change as additional evidence is analyzed.
Author note: Last updated September 8, 2026.