Aviation Accident Summaries

Aviation Accident Summary BFO94LA011

ELMIRA, NY, USA

Aircraft #1

N41S

SCHWEIZER 269C

Analysis

THE PILOT AND CO-PILOT WERE PRACTICING AUTOROTATIONS DURING A TEST FLIGHT. DURING THEIR SEVENTH AUTOROTATION, AT AN ALTITUDE OF ABOUT 100 FEET ABOVE THE GROUND, THE ENGINE LOST POWER. THE AUTOROTATION WAS CONTINUED AND THE CREW REPORTED THEY ENCOUNTERED A DOWNDRAFT. THE HELICOPTER LANDED HARD AND WAS SUBSTANTIALLY DAMAGED. THE CONTROL TOWER REPORTED THE WINDS FROM A MAGNETIC BEARING OF 240 DEGREES AT 15 KNOTS WITH GUSTS TO 30 KNOTS. IN HIS WRITTEN REPORT CONCERNING THE ACCIDENT, THE PILOT SAID THE WINDS WERE FROM A MAGNETIC BEARING OF 230 DEGREES VARIABLE TO 270 DEGREES AT 23 KNOTS WITH GUSTS TO 35 KNOTS. THE MANUFACTURER'S FLIGHT MANUAL STATES: 'CONTROLLABILITY HAS BEEN SHOWN TO BE ADEQUATE IN 20 MPH WINDS FROM ANY DIRECTION.' THE REASON FOR THE ENGINE'S LOSS OF POWER WAS NOT DETERMINED.

Factual Information

On November 15, 1993, about 1100 hours eastern standard time, a Schweizer 269C, N41S, landed hard at the termination of a practice autorotation, at Elmira Airport, Elmira, New York. About 100 feet above the ground, the crewmembers noted a total loss of engine power. The certificated commercial pilot received minor injuries and the certificated commercial co-pilot was not injured. The airplane sustained substantial damage. The local area experimental test flight was being operated by Schweizer Aircraft, Incorporated of Elmira. Visual meteorological conditions prevailed and a flight plan was not filed. An FAA safety inspector examined the aircraft and interviewed the crewmembers on scene. The pilots told the inspector they were performing their seventh practice autorotation when the accident occurred. They said that about 100 feet above the ground during the simulated engine failure autorotative descent, they noted the helicopter's engine had actually failed. They further reported that a "strong downdraft" was encountered and the helicopter landed hard. A weather observation was taken at Elmira Airport at 1058 hours and at that time the winds were from 240 degrees magnetic at 15 knots with gusts to 30 knots. The winds reported by the pilot in the Pilot/Operator Report, NTSB Form 6120.1/2, were from a magnetic bearing of 230 degrees variable to 270 degrees at 23 knots with gusts to 35 knots. Paragraph 5-1 of the Schweizer Aircraft Model 269C Helicopter Pilot's Flight Manual states: "Controllability has been shown to be adequate in 20 mph winds from any direction." The reason for the engine's loss of power was not determined.

Probable Cause and Findings

A LOSS OF ENGINE POWER AT A CRITICAL POINT ON A PRACTICE AUTOROTATION, AND FAILURE OF THE PILOT TO ATTAIN A FLARE FOR THE LANDING. FACTORS RELATED TO THE ACCIDENT WERE: THE ADVERSE WIND AND DOWNDRAFT.

 

Source: NTSB Aviation Accident Database

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