Aviation Accident Summaries

Aviation Accident Summary SEA94LA098

TROUTDALE, OR, USA

Aircraft #1

N2865B

BELL 47G-2

Analysis

WHILE HOVERING IN A VARIABLE, GUSTY WIND, THE STUDENT PILOT FAILED TO MAINTAIN DIRECTIONAL CONTROL OF THE HELICOPTER. THE INSTRUCTOR PILOT TOOK CONTROL OF THE AIRCRAFT, BUT HIS REMEDIAL ACTION WAS NOT ADEQUATE TO PREVENT THE TAIL ROTOR FROM STRIKING THE GROUND.

Factual Information

On April 12, 1994, approximately 1300 Pacific daylight time (PDT), a Bell 47G-2 helicopter, N2865B, collided with the terrain while hovering at Portland-Troutdale Airport, Troutdale, Oregon. The certified flight instructor and his student were not injured, but the aircraft sustained substantial damage. The local instructional flight, which departed the same airport about 15 minutes earlier, was in visual meteorological conditions at the time of the accident. No flight plan had been filed, and there was no report of an ELT activation. According to the FAA inspector who responded to the scene, the dual student, who had a total time of 3.5 hours, was practicing a hover about three to five feet above the ground when the helicopter began a deviation from the desired flight attitude. The instructor took over from the student, but the tail rotor impacted the ground before the instructor was able to complete his desired remedial action. After a post-accident inspection of the aircraft, this same inspector said that he could find no evidence of pre-impact malfunctions or anomalies. The Troutdale Surface Analysis (SA), taken about five minutes prior to the accident, showed that there were rain showers of unknown intensity in all quadrants, and the flight instructor reported that the winds, which he said were gusting to 10 knots, were coming from an "unusual" direction. The instructor said that Troutdale Airport was "...notorious for having very unusual wind directions, speed, turbulence, and wind shear."

Probable Cause and Findings

THE INSTRUCTOR PILOT'S INADEQUATE REMEDIAL ACTION. FACTORS INCLUDE THE DUAL STUDENT'S LACK OF EXPERIENCE, AND HIS FAILURE TO MAINTAIN DIRECTIONAL CONTROL. ANOTHER FACTOR WAS UNFAVORABLE, GUSTY WINDS.

 

Source: NTSB Aviation Accident Database

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