WEEK 2
H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.
TITLE
Training autorotation ends in uncontrolled descent after loss of engine power.
WHAT?
A flight instructor and student pilot were conducting an instructional flight when the instructor initiated a practice autorotation at about 1,100 ft above ground level by reducing the throttle to idle to simulate an engine failure. The engine then experienced a total loss of power. The instructor attempted a restart while the helicopter descended, and both pilots were reportedly involved on the controls during the autorotation. The descent was not sufficiently slowed before impact, and the helicopter struck terrain, rolled over, and sustained substantial damage.
WHERE?
The accident occurred near Howe, Texas, in a rural area with down-sloping grassy terrain adjacent to wooded areas and nearby residential structures.
WHEN?
August 9, 2016, at approximately 2035 local time, during dusk conditions near the end of civil twilight. The final NTSB report was published on September 26, 2017.
HOW?
During the training sequence, the instructor reduced power to idle to initiate a simulated engine failure, but the engine lost power completely. A restart attempt was made during descent, although the flight manual advised conducting a normal autorotation below 2,000 ft agl instead of attempting a restart. The student reported beginning the landing flare at about 25 ft agl but believed the descent rate had not been adequately reduced. The helicopter impacted terrain in a high-speed descent, causing tail boom separation and rollover.
CONDITIONS?
The flight took place under visual meteorological conditions at dusk with light winds and clear visibility. The training maneuver occurred at relatively low altitude, limiting recovery options. The helicopter was set up with dual controls and mixed control inputs were reported. The fuel boost pump switch was found OFF, and the aircraft’s flight manual contained warnings about rapid throttle reductions during autorotation training and the need for suitable landing areas. Post-accident examination found no mechanical anomalies.
OUTCOME?
The instructor sustained fatal injuries and the student pilot sustained serious injuries. The helicopter was substantially damaged. Investigators could not determine the exact reason for the reported engine power loss due to impact damage, but no mechanical failures were identified.
WHY?
- Practice autorotation initiated with throttle reduction practices that increased risk of engine stoppage.
- Unsuitable attempt to restart the engine at low altitude.
- Improper execution of the autorotation following loss of engine power.
- Uncontrolled descent into terrain during the landing phase.
- Flight instructor’s lack of remedial action during the autorotation.
- Instructor and student both making inputs on controls issues during the autorotation..
REFERENCE?
National Transportation Safety Board. (2017, September 26). Aviation investigation final report: Accident number CEN16FA315 (Hughes 269C, N9277R). National Transportation Safety Board. https://data.ntsb.gov/Docket?ProjectID=93803
Note:
Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.
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