NTSB Factual Report

On June 18, 2001, at 2015 central daylight time, an Enstrom F-28A, N612B, piloted by a private pilot, was substantially damaged when it impacted the terrain during takeoff. The flight was conducted under the provisions of 14 CFR Part 91 and was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot received serious injuries and the passenger received minor injuries. The flight was originating at the time of the accident and the destination was the Davenport Municipal Airport, Davenport, Iowa.

In his written report, the pilot said, "...(5) Preflighted, got in, shut doors, sett belts on, headset on, started, warmed up then picked up to a 3 [foot] hover. Everything was in the green and looked normal. I then rotated 180 [degrees] to transition out, stopped, everything looked normal. (6) I then added full power, lower cyclic and slightly raised collective to start moving [forward]. As we climbed to about 15-17 [feet], we heard a coughing sound, then silent. Engine quit, I tried to get it back on the ground as flat and level as possible. You can not auto[rotate] at 17 [feet]."

Federal Aviation Administration publication FAA-H-8083-21 - ROTORCRAFT FLYING HANDBOOK states, "A height/velocity (H/V) diagram, published by the manufacturer for each model of helicopter, depicts the critical combinations of airspeed and altitude should an engine failure occur. Operating at the altitudes and airspeeds shown within the crosshatched or shaded areas of the H/V diagram may not allow enough time for the critical transition from powered flight to autorotation." A copy of the Enstrom F-28A height/velocity diagram is appended to this report.

The helicopter flight manual states in section 8, "... The effects of wind on take-off and landings are important factors and should be considered in the operation of the helicopter; however, in planning critical helicopter operations, the effects of winds can be relied upon to assist in accomplishing landings and take-offs from unobstructed areas. If the helicopter were riding a gust of wind on the final approach and the gust should decrease as the helicopter was approaching a hover, the helicopter would probably rapidly 'settle' if the wind factor was planned on to execute the landing. This condition would also hold true during the initial phase of take-off. ... Another effect of wind that must be considered is the 'lee' effect of the wind over hills, ridges, and obstacles. The downdrafts resulting from these conditions particularly affect the initial phase of take-off or the final phase of landing."

A postaccident examination of the helicopter and accident site was conducted. The helicopter was found facing in a northerly direction in an flat, open, unobstructed field. The field was estimated to be about 15 acres in size. There were buildings to the south of the field. The helicopter control system was examined and no anomalies that could be associated with a preexisting condition were found. The engine was examined and no anomalies were found. Photographs of the accident scene are appended to this report.

The weather at the Davenport Municipal Airport, Davenport, Iowa, was reported as: Observation time 0054 UTC; Winds 200 degrees at 17 knots gusting to 22 knots; Visibility 10 miles; Sky condition clear; Temperature 29 degrees Celsius; Dewpoint 16 degrees Celsius; Altimeter setting 29.89 inches of mercury. The report also contained a remark that the peak winds recorded were 210 degrees at 26 knots at 0038 UTC.

NTSB Probable Cause

The inadequate autorotation and disregarded wind information by the pilot. Factors were the gusting tailwind and the loss of engine power for undetermined reasons.