What Happened
On March 29, 2001, about 7:01 p.m. mountain standard time, Gulfstream III N303GA struck sloping terrain approximately 2,400 feet short of runway 15 at Aspen-Pitkin County Airport, Colorado. The two pilots, flight attendant, and 15 passengers were killed. Avjet operated the charter flight under Part 135, and the airplane was destroyed.
The flight had started well before the final approach. During preflight planning, the first officer obtained a weather briefing and filed an instrument flight plan with Rifle, Colorado, as the alternate. The briefing included a change to the approach procedure and a restriction concerning circling minimums at night.
The crew repositioned the airplane from Burbank to Los Angeles to collect the passengers. The passengers were not there when the airplane arrived. The eventual departure was 41 minutes later than scheduled. A planned flight time of 1 hour 35 minutes put arrival at Aspen at about 6:46 p.m., only 12 minutes before the airport’s applicable nighttime landing cutoff.
The captain knew the time limit. During the flight, the pilots discussed sunset and the allowance of 30 minutes afterward. Their alternate remained Rifle, and the captain said there was time for only one approach at Aspen before they would need to divert.
As they entered the Aspen area, the crew heard another aircraft request another approach after missing its first attempt. The captain asked the controller whether that had been a practice approach. It had not. That information established that reaching the airport visually was already proving difficult for another crew.
The pilots continued looking for a highway and other visual features. Their recorded conversation showed intermittent identification of terrain features, not a shared, continuous view of the runway. The captain told the controller he could almost see up the canyon but did not know the terrain well enough to accept a visual approach.
Then another aircraft reported seeing the airport at 10,400 feet and subsequently landed. That aircraft’s success did not establish what the Gulfstream crew could see at the time and position of its own approach. The Gulfstream continued with the instrument approach.
The airplane descended below the minimum descent altitude without the appropriate runway reference. Darkness and weather limited the crew’s ability to see the mountainous terrain. Before reaching the runway, N303GA struck the slope.
Investigation Findings
The NTSB identified the descent below minimum descent altitude without appropriate visual reference as the probable cause. Minimum descent altitude was the altitude boundary protecting the approach until the required visual transition could be made. Recognizing a highway, river, or town did not establish that the runway environment needed for that transition had been acquired.
Several pressures had converged on the final approach. The late passenger arrival had consumed 41 minutes before takeoff. The airport’s landing restriction then created a deadline at the destination. The NTSB also found that the charter customer had pressured the captain to land. Those were contributing factors, not permission to modify the published approach limits.
The crew had already identified an alternate and discussed a one-approach limit. That is an important part of the sequence. An escape plan existed, but the protection depended on executing it when the approach could not be completed within its limits. Naming the alternate before arrival did not itself stop an unsafe descent.
The investigation also found a problem outside the cockpit. The FAA’s March 27 notice concerning the nighttime restriction for the VOR/DME-C approach was unclear, and the FAA had failed to communicate the restriction to the Aspen tower. The Board included both shortcomings in its contributing factors.
Those administrative problems did not erase the altitude finding. The probable cause separated the crew’s operation below minimums from the unclear notice, the darkness and weather, and the pressure to land. Keeping those elements distinct explained how several weaknesses could converge without making any single factor an excuse for the final descent.
NTSB Probable Cause
the flight crew’s operation of the airplane below the minimum descent altitude without an appropriate visual reference for the runway.
Contributing to the cause of the accident were the Federal Aviation Administration’s (FAA) unclear wording of the March 27, 2001, Notice to Airmen regarding the nighttime restriction for the VOR/DME-C approach to the airport and the FAA’s failure to communicate this restriction to the Aspen tower; the inability of the flight crew to adequately see the mountainous terrain because of the darkness and the weather conditions; and the pressure on the captain to land from the charter customer and because of the airplane’s delayed departure and the airport’s nighttime landing restriction.
Safety Lessons
The following takeaways apply the investigation findings to flight planning and cockpit decisions.
- Make the diversion trigger independent of the customer. Brief the alternate and the conditions that require it before time pressure builds. A passenger deadline belongs in trip planning; it cannot determine whether the required visual reference exists at minimums.
- Use the visual reference required for your approach. Intermittent views of ground features and another aircraft reporting the airport are information, not a substitute for your own required runway reference. Maintain the published limits and execute the applicable missed approach when the conditions for continuing are not met.
- Resolve restrictions before the approach. Unclear notices and operating deadlines need attention before workload peaks. If a restriction cannot be resolved in time, preserve an alternate plan that does not depend on interpreting it in the most favorable way.
Watch the Full Analysis
Frequently Asked Questions
Q: What caused the 2001 Aspen Gulfstream crash?
A: The NTSB found that the crew descended below minimum descent altitude without appropriate visual reference for the runway. Weather, darkness, unclear FAA notice wording, and pressure to land contributed.
Q: How many people died in the Aspen Gulfstream III crash?
A: All 18 occupants died: two pilots, one flight attendant, and 15 passengers.
Q: Did passenger pressure contribute to the Aspen accident?
A: Yes. The NTSB identified pressure from the charter customer, the delayed departure, and the airport nighttime landing restriction among the contributing factors.
Sources and References
