Aviation Accident Summaries

Aviation Accident Summary LAX08TA116

Logan, UT, USA

Aircraft #1

N6358Z

Hughes TH-55

Analysis

The helicopter was registered to, and operated by a state university. The public-use flight was conducted for the purpose of demonstrating rotor blade tracking and balancing to an aviation maintenance technician class. The helicopter was placed facing south into the wind on the asphalt ramp about 150 feet in front of the maintenance hangar. The doors of the hangar face north, and the hangar "seemed to block the wind in the run-up area." The pilot described the weather as "quite windy (20-25 knots est.) with scattered cumulus, very gusty, temperature around 50 degrees." In an interview conducted on the day of the accident, the pilot told a police officer that he had lifted the helicopter to a hover at 6 to 8 inches above the ground and was about to set it down, but mistakenly rolled the throttle on instead of rolling it off. The helicopter lifted to just above the height of the hangar and was caught by a gust of wind. The pilot attempted to descend, but when the helicopter descended below the height of the hangar, it "lost the wind lift and began to descend too fast." Initially the pilot reported to the Safety Board investigator that he intended to fly, however, in a written report submitted 11 days after the accident, the pilot stated that he had "no intent or expectation of flight," and that he "suddenly and unexpectedly" found himself "5 to 10 feet in the air, out of control." The helicopter was drifting toward the students who were standing about 100 feet away. The pilot attempted to turn away from the students and set the helicopter down as quickly as possible. The helicopter touched down tail low and hard on the left rear skid, the main and tail rotor blades contacted the ground, and the helicopter rolled on to its left side. The pilot's medical certificate and flight review were expired. He reported no flight hours in the 90 days preceding the accident, and he told the police officer that "it had been a while" since he had flown a helicopter. Following the accident, the university implemented changes in class procedures for all maintenance courses. The new procedures include having a current, appropriately rated pilot at the controls for all starting and running operations, including both airplanes and helicopters. Also, run-ups will now be performed only in designated areas and calm weather conditions.

Factual Information

On April 18, 2008, about 1600 mountain daylight time, a Hughes TH-55 helicopter, N6358Z, sustained substantial damage when it landed hard and rolled over following a loss of control while hovering at the Logan-Cache Airport, Logan, Utah. The private pilot, the sole occupant, was not injured. The helicopter was registered to, and operated by, Utah State University (USU). The public-use flight was conducted for the purpose of demonstrating rotor blade tracking and balancing to an aviation maintenance technician class. Visual meteorological conditions prevailed, and no flight plan was filed. During a telephone interview conducted by the National Transportation Safety Board investigator-in-charge (IIC) on April 18, 2008, the pilot reported that a gust of wind caught the helicopter and he lost control. As he attempted to regain control, the helicopter landed hard, rolled over, and came to rest on its left side. The tail boom was buckled, and the main rotor blades were bent and twisted. In response to a direct question from the IIC, the pilot stated that he intended to fly the helicopter. According to a report prepared by the Logan City Police Department, an officer interviewed the pilot on April 18, 2008, and the pilot reported that he was "demonstrating a lift into hover" for USU flight students. The maneuver was to involve "lifting the craft 6 to 8 inches off of the ground and to check the track of the main rotor blades." The pilot explained to the officer that he had lifted the helicopter and was about to set it down, but mistakenly rolled on the throttle instead of rolling it off. The helicopter lifted to just above the height of the USU hangar and was caught by a gust of wind. The pilot attempted to descend, but when the helicopter descended below the height of the hangar, it "lost the wind lift and began to descend too fast." The pilot was unable to recover before the helicopter contacted the ground. The pilot told the officer that he had many years of flight experience but stated that "it had been a while" since he had flown a helicopter. In the Pilot/Operator Aircraft Accident/Incident Report (NTSB Form 6120.1) submitted on April 29, 2008, the pilot stated that he had "no intent or expectation of flight." He reported that he was instructing a class that was in the final phase of completing a 100-hour inspection on the helicopter. The inspection was complete to the point of engine run-up checks and a track and balance check. The helicopter was placed facing south into the wind on the asphalt ramp about 150 feet in front of the maintenance hangar. The doors of the hangar face north, and the hangar "seemed to block the wind in the run-up area." The pilot described the weather as "quite windy (20-25 knots est.) with scattered cumulus, very gusty, temperature around 50 degrees." The pilot reported that he was completing the run-up phase of the inspection with the class observing. He "suddenly and unexpectedly" found himself "5 to 10 feet in the air, out of control." The helicopter was drifting toward the students who were standing about 100 feet away. The pilot attempted to turn away from the students and set the helicopter down as quickly as possible. The helicopter touched down tail low and hard on the left rear skid, the main and tail rotor blades contacted the ground, and the helicopter rolled on to its left side. The pilot held a private pilot certificate with airplane single engine land and helicopter ratings. He stated that his medical certificate and flight review were expired. He reported that he had accumulated in excess of 4,000 total flight hours, of which approximately 130 hours were in helicopters, with 65 hours in the accident helicopter make and model. He reported no flight hours in the 90 days preceding the accident. The reported winds at the airport at 1551 were from 230 degrees at 15 knots, gusting to 24 knots. Following the accident, USU implemented changes in class procedures for all maintenance courses. The new procedures include having a current, appropriately rated pilot at the controls for all starting and running operations, including both airplanes and helicopters. Also, run-ups will now be performed only in designated areas and calm weather conditions.

Probable Cause and Findings

The pilot's inadequate compensation for the wind conditions and failure to maintain control of the helicopter while hovering. Contributing to the accident were the wind gusts and the pilot's lack of recent experience in helicopters.

 

Source: NTSB Aviation Accident Database

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