GULFSTREAM AMERICAN CORP AA-5A — Baxter Pass, CO, 2008

GULFSTREAM AMERICAN CORP AA-5A — Baxter Pass, CO

2 fatal

Date	September 7, 2008
Location	Baxter Pass, CO
Aircraft	GULFSTREAM AMERICAN CORP AA-5A
Purpose of flight	Aerial Observation
Conditions	Visual Meteorological Cond
Phase / occurrence	Uncontrolled descent Collision with terr/obj (non-CFIT)
Pilot age	60
Pilot total time	Unknown
Time in type	Unknown
Fatalities	2

Probable cause

The pilot's failure to maintain adequate airspeed during a turn, resulting in an unrecoverable aerodynamic stall.

NTSB findings

Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C

What happened

Witness statements and recovered GPS data revealed that the commercial pilot and passenger were conducting aerial patrol of an underground pipeline. GPS data overlaid on a map of the pipeline route indicate that the pilot flew a track that was offset to the right of the pipeline, and then initiate a 90-degree left turn during the last 30 seconds of flight. During the offset and start of the turn, the airplane climbed 102 feet and decelerated from 95 miles per hour to 67 miles per hour. Density altitude was about 9,350 feet. Impact signatures and wreckage distribution indicated the airplane impacted terrain in a steep nose-low attitude, consistent with an aerodynamic stall. Examination of the wreckage showed no evidence of any pre-impact mechanical anomalies.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.