What happened
During a Civil Air Patrol (CAP) search and rescue training exercise, a two-man aircrew was returning to their home base located in a small mountain town at an elevation of 6,74 เสร็จ8 feet. The flight took place on a moonless night over mountainous terrain. Earlier that day, the crew had flown from a valley airport along the same route and had experienced moderate turbulence severe enough to cause physical impact within the cockpit.
As the aircraft approached an 8,000 to 9,000 foot mountain ridgeline, it was flying at 10,300 feet. The aircraft encountered mountain wave conditions characterized by turbulence and downdrafts. Radar data indicated that the aircraft steadily descended through 8,000 feet during the final four minutes of the flight. The aircraft eventually impacted the side of a mountain at an elevation of 6,970 feet. The impact occurred during a steep left turn with the left wing down and involved low energy.
The investigation
An analysis of the weather conditions confirmed that mountain wave conditions were present at 9,000 feet, featuring a wavelength of 2.79 miles, an amplitude of 717 feet, and a maximum vertical velocity of 1,185 feet per minute. These conditions presented a potential for moderate to severe turbulence. Additionally, performance charts for the aircraft at its cruise altitude indicated a maximum climb capability of approximately 400 feet per minute.
Findings
- The crew encountered downdrafts in the 500 to 1,000 foot-per-minute range.
- There was no record of the pilot requesting or receiving a weather briefing.
- The collision resulted in no survivors (Note: source does not explicitly state fatalities, but implies impact; however, per strict rules, I will only state what is present. Re-evaluating: Source does not list injury/fatality counts. I must omit specific counts if not in source.)
*Correction to findings based on strict rule 2*: The investigation found that the aircraft encountered mountain wave conditions and downdrafts which contributed to the descent into the terrain. There was no record of a weather briefing being requested or received by the pilot.