ASN Wikibase Occurrence # 68304
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| Date: | Sunday 20 September 2009 |
| Time: | 13:09 |
| Type: |  Robinson R22 Beta |
| Owner/operator: | Hillsboro Aviation Inc |
| Registration: | N956SH |
| MSN: | 0956 |
| Year of manufacture: | 1989 |
| Total airframe hrs: | 10147 hours |
| Engine model: | Lycoming O-320-B2C |
| Fatalities: | Fatalities: 2 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Forest Grove, OR -
 United States of America
|
| Phase: | En route |
| Nature: | Training |
| Departure airport: | Hillsboro Airport, OR (HIO) |
| Hillsboro Airport, OR (HIO) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot under instruction was preparing for a certified flight instructor (CFI) check ride and was in the left seat. The CFI was in the right seat, and the two airmen were going to practice autorotations with power recoveries. A witness with helicopter experience observed several uneventful autorotations and then stopped watching; another witness heard a bang. The witnesses then observed the helicopter descending upright with the left skid low. Investigators examined the wreckage and observed signatures indicating that the engine and main rotor blades were rotating at a low speed at impact. The main rotor blades were also coned upward, which is indicative of a low main rotor rpm state. A safety notice issued by the helicopter's manufacturer notes that main rotor blade stall due to low main rotor rpm causes a high percentage of helicopter accidents. It points out that the stall causes the main rotor rpm to rapidly decrease, and leads to an immediate uncontrolled descent.
Probable Cause: The flight crew’s failure to maintain adequate main rotor speed while maneuvering, which resulted in a main rotor blade stall and an uncontrolled descent into terrain.
Accident investigation:
 |
|
Sources:
NTSB
FAA register: 2. FAA: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=956SH
Location
Images:
Photo(c): NTSB
Media:
20 SEP 2009: Robinson R22 Beta N956SH suffered an accident, Forest Grove, OR, 2 fatalities: Aircraft impacted te.. http://bit.ly/2cUsS
— Aviation Safety Net (@AviationSafety) September 21, 2009
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 20-Sep-2009 21:02 | Geno | Added |
| 03-Oct-2016 20:39 | Dr.John Smith | Updated [Time, Operator, Location, Phase, Departure airport, Destination airport, Source, Embed code, Damage, Narrative] |
| 03-Oct-2016 20:44 | Dr.John Smith | Updated [Source, Embed code] |
| 21-Dec-2016 19:25 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 02-Dec-2017 16:17 | ASN Update Bot | Updated [Other fatalities, Departure airport, Destination airport, Source, Embed code, Narrative] |
| 26-Feb-2022 00:24 | Captain Adam | Updated [Other fatalities, Location, Departure airport, Destination airport, Source, Embed code, Narrative, Photo] |
Corrections or additions? ... Edit this accident description
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