ASN Wikibase Occurrence # 138553
This record has been locked for editing.
| Date: | Thursday 15 September 2011 |
| Time: | 12:23 |
| Type: |  Van's RV-6A |
| Owner/operator: | Private |
| Registration: | N641JC |
| MSN: | 60235 |
| Total airframe hrs: | 1052 hours |
| Engine model: | Lycoming O-320 SERIES |
| Fatalities: | Fatalities: 1 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | West Jordan, UT -
 United States of America
|
| Phase: | En route |
| Nature: | Private |
| Departure airport: | Sierra Vista, AZ (FHU) |
| Salt Lake City, UT (U42) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
While approaching the airport at the conclusion of a 4-hour flight, the pilot announced his intention over the common traffic frequency to join the traffic pattern. A short time later, an undiscernible distress transmission was made over the frequency. A few seconds later, the airplane was observed spiraling to the ground. Global positioning system data recovered from the airplane revealed that it was traveling at an appropriate airspeed for entry into the downwind leg of the traffic pattern with a sufficient margin above the stall speed to maintain flight. It then made an abrupt left turn, resulting in a spiral dive, which progressed into a spin. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
No evidence of a bird-strike was found, and review of radar data did not reveal the presence of other aircraft in the vicinity just prior to the accident. However, radar data did reveal that the airplane passed through a cluster of primary targets (with no altitude information) at the time of the accident. Such primary targets could potentially be radar system anomalies, thermal air currents, or bird reflections. According to a bird mitigation specialist, large birds, or flocks of smaller birds, are often present at that time of year, and such birds typically fly circling patterns in thermal air currents at traffic pattern altitudes.
The pilot’s abrupt maneuver during the approach was consistent with an avoidance maneuver. The maneuver, which was calculated to be a 65-degree angle of bank to the left, most likely placed the airplane into an accelerated stall condition, which developed into a spin. The airplane was loaded toward its aft center of gravity limit, which could have increased its pitch sensitivity, thereby exacerbating the turn. A successful recovery from an unintentional stall-spin at pattern altitude is extremely unlikely.
Probable Cause: The pilot’s execution of an abrupt maneuver, likely to avoid birds, which resulted in a stall and spin.
Accident investigation:
 |
|
Sources:
NTSB
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 15-Sep-2011 15:02 | RobertMB | Added |
| 15-Sep-2011 21:49 | RobertMB | Updated [Aircraft type, Registration, Cn, Operator, Source, Narrative] |
| 16-Sep-2011 00:21 | Anon. | Updated [Aircraft type, Registration, Cn, Operator, Source] |
| 16-Sep-2011 06:12 | RobertMB | Updated [Aircraft type, Operator, Source, Narrative] |
| 27-Sep-2011 12:00 | Anon. | Updated [Aircraft type, Departure airport, Destination airport, Source, Narrative] |
| 21-Dec-2016 19:26 | ASN Update Bot | Updated [Time, Damage, Category, Investigating agency] |
| 08-Apr-2017 19:23 | junior sjc | Updated [Location, Departure airport, Destination airport, Source, Damage, Narrative] |
| 27-Nov-2017 17:14 | ASN Update Bot | Updated [Aircraft type, Other fatalities, Departure airport, Destination airport, Source, Damage, Narrative] |
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