ERA17LA046
2016-11-15 · West Chester, Pennsylvania, United States · None · 1 aircraft · Status: Completed
Airport OQN
Aircraft involved
Probable cause & findings
The flight instructor's decision to continue the practice autorotation in known gusting wind conditions, which resulted in a hard landing and roll over.
Factual narrative
On November 15, 2016, about 1500 eastern standard time, a Robinson R22, N306RL, was substantially damaged 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 the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Day, visual meteorological conditions prevailed at the time, and no flight plan was filed. The local flight departed OQN about 1430.The flight instructor reported that he was demonstrating straight-in autorotation landings to a power recovery using the runway. The wind was generally from the north, but shearing from the northeast to the northwest, horizontally. 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. An inspector with the Federal Aviation Administration responded to the accident site and 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. He determined that the helicopter was operated within the aircraft's 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, which placed the helicopter near the upper weight limit. His examination of the wreckage did not reveal evidence of a mechanical failure or malfunction. He reported that 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 with the helicopter that would have precluded normal operation. The flight instructor was demonstrating straight-in autorotations to a power recovery over the runway. He stated that the wind during the flight was generally from the north, but shearing horizontally to the northeast/northwest. He began to flare the helicopter about 40 ft above the ground. About 20 ft above the ground, a large wind gust with a horizontal wind shear resulted in a drift to the right and loss of tail rotor effectiveness. He corrected the drift and heading with flight control inputs, returned to the runway area, and continued the flare. During the last portion of the flare, the helicopter encountered a vertical wind shear and climbed about 20 ft. At that point, "all wind stopped," and the helicopter descended. The instructor attempted a power recovery; however, the helicopter landed hard on the skids with some lateral motion. The helicopter bounced, the left skid broke, and the helicopter rolled and came to rest on its left side. The flight instructor did not report any preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Postaccident examination of the wreckage confirmed substantial damage to the airframe and main rotor blades; there was no evidence of a preimpact mechanical failure or malfunction. Additionally, the flight instructor reported that there were no preaccident mechanical malfunction or failures that would have precluded normal operation. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
FAA avdata. C = Cause, F = Factor.
- C Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Instructor/check pilot - C
- C Personnel issues-Task performance-Use of equip/info-Aircraft control-Instructor/check pilot - C
- C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Descent/approach/glide path-Not attained/maintained - C
- — Environmental issues-Conditions/weather/phenomena-Wind-Gusts-Effect on operation
Verbatim from NTSB's published report. Source file
NTSB_2016_ERA17LA046.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
Matched on aircraft type or causal vocabulary (wind shear). All research papers
- NASA NTRS 2019 · Conference Paper Optimal recovery from microburst wind shear
The flight path of a twin-jet transport aircraft is optimized in a microburst encounter during approach to landing. The objective is to execute an escape maneuver that maintains safe ground clearance …
- NASA NTRS 2019 · Contractor Report (CR) An Examination of Aviation Accidents Associated with Turbulence, Wind Shear and Thunderstorm
The focal point of the study reported here was the definition and examination of turbulence, wind shear and thunderstorm in relation to aviation accidents.
- NASA NTRS 2019 · Conference Paper Analysis of extreme wind shear
New methods utilizing extreme value statistical theory are applied in the analysis of the largest wind component shear in a wind profile as a function of shear layer thickness and season.
- NASA NTRS 2019 · Technical Memorandum (TM) Probabilities of zero wind shear phenomena based on Rawinsonde data records
Probabilities of zero wind shear occurence and depth based on rawinsonde data records
- NASA NTRS 2019 · Contractor Report (CR) A Wind Shear Mechanism for Producing Sporadic E by Concentrating Minor Meteoric Ions
Wind shear mechanism for producing sporadic E layer by concentrating minor meteoric ions
- NASA NTRS 2019 · Technical Memorandum (TM) Some aspects of wind shear in the upper atmosphere
Hydrodynamic turbulence and wind shear in upper atmosphere