NYC03LA195

According to the pilot of the accident airplane, while he was on the downwind leg of the traffic pattern, he heard a helicopter announce over the UNICOM frequency that he was "inbound...5 miles to the northeast." The pilot continued in the pattern, and when he was at an altitude of 100 feet on final approach, he obtained visual contact with the helicopter, which was descending towards the taxiway adjacent to runway 30, about 1/3 down the runway. The pilot then decided to initiate a go-around; however, the airplane had already "lost its lift," and only climbed to about 20-30 feet before it was blown "by the propwash of the helicopter" to the left of the runway. The right wing dropped, impacted the runway, and the airplane "cartwheeled," coming to rest on the grassy area between the runway and taxiway. A review of FAA Advisory Circular (AC) 90-23E, Wake Turbulence, revealed: "A hovering helicopter generates a downwash from its main rotor(s) similar to the "prop wash" of a conventional aircraft. However, in forward flight, this energy is transformed into a pair of strong, high-speed trailing vortices similar to wing-tip vortices of larger fixed-wing aircraft. Pilots should avoid helicopter vortices since helicopter forward flight airspeeds are often very low which generate exceptionally strong wake turbulence."

On September 5, 2003, at 1635 eastern daylight time, N6183J, a Piper PA-28-140, was substantially damaged while landing at the Somerset Airport (SMQ), Somerville, New Jersey. The certificated student pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the flight which originated at the Solberg-Hunterdon Airport (N51), Readington, New Jersey. The solo instructional flight was conducted under 14 CFR Part 91.

According to the pilot, he entered the traffic pattern at Somerset Airport, on a 45-degree, left downwind for runway 30. While on the downwind leg of the traffic pattern, the pilot heard a helicopter announced over the UNICOM frequency that he was "inbound...5 miles to the northeast." The pilot advised over the frequency, that he did not have the helicopter in sight, and reported turning "left base for 30, Somerset." At an altitude of 500 feet, the pilot still did not see the helicopter, and announced his position over the UNICOM, as he turned onto final approach. After turning onto final, the pilot observed a black helicopter ahead, below and to the right of his approach for runway 30. After announcing his turn onto final approach, the pilot heard over the UNICOM frequency, "...helicopter will keep right."

As the airplane was at an altitude of 100 feet over the tree line, at the approach end of runway 30, the pilot observed the helicopter descending towards the taxiway adjacent to runway 30, about 1/3 down the runway, between the runway and the parked aircraft on the ramp. The pilot then decided to initiate a go-around, and applied full power.

The pilot reported that the airplane seemed to have "lost its lift," and only climbed to about 20-30 feet before being blown "by the propwash of the helicopter" to the left of the runway. The right wing dropped and impacted the runway. The airplane "cartwheeled," coming to rest on the grassy area between the runway and taxiway, ahead of the helicopter.

According to the co-pilot of the helicopter (a Bell 430, N431HF), the flight approached Somerset from the east, and his first call on the UNICOM frequency was announcing the helicopter's position, "about 15 miles out." He made two more transmissions at 10 miles out, and 5 miles out, both times announcing the helicopter's position and altitude. The co-pilot stated that he did hear a pilot of another airplane announce his intention to land on runway 30, as the helicopter approached the airport. The co-pilot made a final transmission over the UNICOM frequency, stating the helicopter was two miles east of the airport with intentions of entering a right base and final to the taxiway grass area, right of runway 30. At that point, the helicopter crew had visual contact with the airplane on left base to runway 30, and it appeared the airplane was 1/2-mile behind the helicopter, as the helicopter turned final. The helicopter crew "shot the approach" to the grass area right of runway 30, and were waiting for another airplane to clear the taxiway when the co-pilot observed the accident airplane in a 75 degree right bank at an altitude of 50 to 70 feet, left of the runway. The airplane then impacted the runway with the nosegear and propeller simultaneously and spun clockwise, coming to rest on the grass on the right side of the runway.

Winds reported at Somerset, at 1553, were from 010 degrees at 9 knots.

The pilot of the accident airplane reported 47 hours of total flight experience, all in make and model.

A review of FAA Advisory Circular (AC) 90-23F, Wake Turbulence, revealed: "A hovering helicopter generates a downwash from its main rotor(s) similar to the "prop wash" of a conventional aircraft. However, in forward flight, this energy is transformed into a pair of strong, high-speed trailing vortices similar to wing-tip vortices of larger fixed-wing aircraft. Pilots should avoid helicopter vortices since helicopter forward flight airspeeds are often very low which generate exceptionally strong wake turbulence."

The AC further stated that pilots should avoid operations within distances of 3 times the rotor diameter of a hovering helicopter.