Incident Overview
On November 15, 2016, about 1500 eastern standard time, a Robinson R22 helicopter, registration N306RL, sustained substantial damage during a practice autorotation landing at Brandywine Airport (OQN), West Chester, Pennsylvania. The flight instructor and a student pilot were not injured. The helicopter was privately owned and operated under 14 Code of Federal Regulations Part 91 as an instructional flight. Day visual meteorological conditions prevailed, and no flight plan was filed. The local flight had departed OQN about 1430.
Sequence of Events
The flight instructor reported that he was demonstrating straight-in autorotation landings with power recovery using the runway. The wind was generally from the north but experienced horizontal shear from the northeast to the northwest. During an autorotation to runway 9/27, he began to flare about 40 feet above the ground. At 20 feet, a large gust with a horizontal wind shear caused the helicopter to drift to the right and lose tail rotor effectiveness. He corrected the drift and heading with flight control inputs, returned to the runway, and continued the flare. During the last portion of the flare, a vertical wind shear was encountered, and the helicopter climbed, uncommanded, about 20 feet. At that point, "all wind stopped," and the helicopter descended. He attempted a power recovery; however, the helicopter landed hard on the skids, with some sideward motion. The helicopter bounced, the left skid broke, and the aircraft rolled and came to rest on its left side. The two pilots egressed the helicopter and were met by first responders.
Examination and Findings
An inspector with the Federal Aviation Administration examined the wreckage. Structural damage to the airframe was confirmed. The main rotor blades were deformed from impact forces, and the tail boom was partially separated. The inspector determined that the helicopter was operated within its weight and balance limitations at the time of the accident; however, it was operated at the forward center of gravity limit. The pilots weighed about 200 pounds each, placing the helicopter near the upper weight limit. The examination did not reveal evidence of a mechanical failure or malfunction. The surface wind at the time of the accident varied between 330 and 350 degrees at 11 to 14 knots. The flight instructor did not report any preaccident mechanical malfunction or failures that would have precluded normal operation.