NTSB Factual Report

On October 13, 2012, about 0920 eastern daylight time, two helicopters in a flight of five, a Hughes 369A, N369SN (Chalk 3), and another Hughes 369A, N546 (Chalk 4), collided during hover-taxi while landing at Brandywine Airport (OQN), West Chester, Pennsylvania. The 3 occupants in Chalk 3 and the 2 occupants in Chalk 4 were not injured. Chalk 4 sustained substantial damage to all four main rotor blades and the tail pylon. Chalk 3 sustained substantial damage to the left landing skid. Both helicopters were operated under the provisions of 14 Code of Federal Regulations Part 91as personal flights. Visual meteorological conditions prevailed.

The flight of helicopters, each designated "Chalk 1" through "Chalk 5," were enroute to an annual all-helicopter airshow. The pilots of Chalk 1, 3, and 4 provided written statements, and their statements were consistent throughout. They each said that "Flight Lead," Chalk 5 was flying in the trail aircraft position. According to their statements, the flight arrived in trail formation and overflew runway 09 at 1,200 feet and 60 knots. Chalk 1 stated he entered left traffic, and while on the left base leg for landing, Chalk 3 announced airplane traffic on final approach to Runway 09. Chalk 1 stated he turned left prior to the runway, and initiated a go-around on the north side of the runway. Flight lead, in the trail aircraft, then announced over the flight's internal radio frequency to, "Break left or land."

According to Chalk 3, he then "initiated a steep approach" to land on runway 09, and while he maintained visual separation from Chalk 2, noticed the rotor disk of another helicopter immediately below and to the right of his just as contact between the two was made, which separated the left landing gear skid. Chalk 3 then egressed his passengers from a hover, and repositioned the helicopter back to LNS and sought the assistance air traffic control (ATC) and crash/fire/rescue services. The helicopter landed without further incident.

According to Chalk 4, Chalk 1 announced a go-around, but Chalk 5 gave the command to break left or land. At that point, he had Chalks 1, 2, and 3 in sight. Chalk 4 then confirmed the airplane traffic was "no factor" and had initiated a go-around on the south side of the runway. When he looked back on the formation in front of him, he had only Chalk 2 in sight, and had lost visual contact with Chalks 1 and 3. Chalk 4 then performed a "normal" approach to a 5-foot hover over the runway centerline, began a hover-taxi to parking, and about 20 seconds later "felt" the contact with the other helicopter. He then landed the helicopter without further incident.

The pilot of Chalk 4 held a private pilot certificate, with a rating for a rotorcraft-helicopter. He reported 586 total hours of flight experience, of which 253 hours were in the accident helicopter make and model.

The pilot of Chalk 3 held a commercial pilot certificate, with a rating for a rotorcraft-helicopter. He reported 1,617 total hours of flight experience, 92 hours of which were in the accident helicopter make and model.

Each of the accident helicopters had 100-hour inspections performed during the year prior to the accident, and each pilot reported there were no mechanical deficiencies with either helicopter that would have prevented normal operation.

Examination of briefing slides provided to the group by the flight lead (Chalk 5) revealed that the aircraft position order briefed on the slides was not the order flown. There were no slides that provided guidance for loss of visual contact or an inadvertent encounter with instrument meteorological conditions. There was no slide that identified flight lead would fly from the trail position of the formation.

NTSB Probable Cause

The pilot’s failure to see and avoid the preceding helicopter while maneuvering for landing. Contributing to the accident were the flight lead pilot’s inadequate preflight briefing and in-flight instruction to the formation pilots, which resulted in the loss of the formation flight's integrity and the pilots’ situational awareness within the flight.