ASN Wikibase Occurrence # 353575
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Date: | Thursday 12 November 1998 |
Time: | 20:15 LT |
Type: | Bell 206B |
Owner/operator: | Helicopter Inc |
Registration: | N32KY |
MSN: | 4039 |
Year of manufacture: | 1989 |
Total airframe hrs: | 3169 hours |
Engine model: | Allison 250-C20J |
Fatalities: | Fatalities: 0 / Occupants: 3 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Louisville, KY -
United States of America
|
Phase: | En route |
Nature: | Survey |
Departure airport: | , KY (43KY) |
Destination airport: | |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:The pilot reported that while in cruise at 700 feet AGL the helicopter yawed left, followed by a low rotor caution light being illuminated. The pilot executed an autorotation landing under dark night conditions to a flat, wet, muddy surface. During the landing the helicopter's skids began to dig in, and the helicopter began to nose over. The pilot applied aft cyclic in an effort to prevent the nose over during which the rotor blades impacted and severed the tailboom. Post-crash examination revealed 51 gallons of fuel aboard and no spreading deformation to the helicopter's skids. Further examination revealed that the 'B' nut on the PC air line from the power turbine governor to the fuel control unit was backed off about 2-3 'flats.' The engine was successfully operated in a test cell in an 'as received' condition. During subsequent engine runs, the 'B' nut was tightened and loosened to one flat with no variation in engine performance. The 'B' nut was also completely removed resulting in a stagnant start. According to the manufacturer, a breach in the PC air line will allow air pressure to bleed out and result in the fuel control unit automatically shifting to a minimum flow condition (less than idle). The test cell conditions may or may not have duplicated the vibratory conditions in the aircraft's airframe at the time of the power loss.
Probable Cause: A loose 'B' nut on the aircraft's PC Air line which resulted in fuel starvation, and the pilot's abrupt application of aft cyclic to prevent a nose over. Contributing factors were soft terrain and dark night conditions.
Accident investigation:
|
| |
Investigating agency: | NTSB |
Report number: | IAD99LA015 |
Status: | Investigation completed |
Duration: | 1 year and 4 months |
Download report: | Final report |
|
Sources:
NTSB IAD99LA015
Location
Revision history:
Date/time | Contributor | Updates |
10-Mar-2024 08:15 |
ASN Update Bot |
Added |
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