Loss of control and terrain impact of twin-turbojet aircraft

2 fatalities • Sierra Blanca, United States of America • Flight

A twin-turbojet transport aircraft crashed into terrain following a period of lost communication and an uncontrolled descent after exceeding maximum operating speeds.

What happened

During the descent toward its destination, the twin-turbojet aircraft was cleared to descend from FL 390 to 10,000 feet. The crew initiated a descent rate of 4,000 feet per minute. While passing through FL 219, air traffic control instructed the pilot to contact approach control. The pilot responded with an incorrect frequency and an unintelligible word. Despite attempts by the controller to rectify the communication error, no further contact was established with the crew.

During a brief silence in the final transmission, a 1680 Hz tone was detected for 0.1 seconds. This frequency corresponds to either the overspeed or cabin altitude warning systems, both of which were destroyed in the crash. Radar tracking showed the aircraft climbing to FL 231 before entering a steep, rapid descent. During this phase, the aircraft exceeded its maximum operating airspeed of 300 knots calibrated. Shortly before hitting the ground, the right wing and portions of the right horizontal stabilizer and elevator detached from the airframe, landing roughly 200 to 250 feet from the primary impact site. The crash resulted in fatalities and the total destruction of the aircraft.

Findings

Investigations revealed no mechanical issues with the engines or the airframe that would have caused the loss of control. While the aircraft exceeded its rated maximum operating speed, manufacturer data suggests the model is capable of flying at speeds up to 400 knots without losing control. The cockpit voice recorder was present on the aircraft but failed to capture the flight sequence.

Probable cause

The aircraft entered an uncontrolled descent after exceeding its maximum operating airspeed during the descent phase.

Frequently asked questions

What happened in the 2001-12-10 Learjet 24 accident near Sierra Blanca, United States of America?

A twin-turbojet transport aircraft crashed into terrain following a period of lost communication and an uncontrolled descent after exceeding maximum operating speeds.

Were there any fatalities in the 2001-12-10 Learjet 24 accident?

The accident was fatal, resulting in 2 fatalities.

What aircraft was involved and where did it happen?

The accident on 2001-12-10 involved a Learjet 24, registration N997TD, operated by Air Cargo Express (Fort Wayne), at Sierra Blanca, United States of America.

What was the probable cause of the accident?

The aircraft entered an uncontrolled descent after exceeding its maximum operating airspeed during the descent phase.

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