What happened
On April 25, 2009, a Lockheed P2V-7 Neptune, registration N442NA, crashed into a ridge approximately one and one-half miles north of Stockton, Utah. The aircraft, operated by Neptune Aviation Services, was performing a repositioning flight from Missoula, Montana, to Alamogordo, New Mexico, to support firefighting efforts.
At the time of the accident, the crew was flying in an area characterized by low ceilings and restricted visibility. The flight crew had been descending through various altitudes to attempt to remain in Visual Flight Rules (VFR) conditions while navigating around weather. During the final stages of the flight, the aircraft was descending through approximately 5,600 feet MSL. At 10:04 MDT, the aircraft impacted the northwest upslope of a ridge at an elevation of about 5,630 feet.
The crash resulted in 3 fatal injuries, claiming the lives of the two pilots and one passenger.
The investigation
Investigators examined the wreckage and recovered the cockpit voice recorder (CVR), which provided 31 minutes of audio prior to the impact. The CVR revealed that the crew discussed descending to lower altitudes to stay beneath the clouds and specifically mentioned trying to "stay under this stuff." The recording showed that while the First Officer questioned whether their altitude was sufficient to clear upcoming terrain approximately ten minutes before impact, the Captain did not respond, and the First Officer did not further challenge the issue.
Analysis of the onboard flight data indicated that there was no rapid pitch or roll movement immediately preceding the impact. Instead, the pitch angle rose at a constant rate from level flight to approximately four degrees nose up, and the bank angle progressed to about 11 degrees left bank just before the aircraft struck the terrain.
Mechanical examination of the Lockheed P2V-7 found no evidence of engine malfunction or loss of control. The engines showed no evidence of compressor blade damage or internal failure. The aircraft had been converted to a fire bomber and, as a result, lacked de-icing or anti-icing capabilities for its flight surfaces.
Findings
- The flight crew failed to maintain terrain clearance during low-altitude flight in conditions with low ceilings and limited visibility.
- The crew failed to adequately monitor their position relative to the rising terrain ahead.
- There was a lack of effective crew resource management (CRM) communication regarding the approaching terrain.