2 fatalities

2001-08-24: Learjet 25 (N153TW) — Ameristar Jet Charter — Ithaca-Tompkins, United States of America

Ithaca-Tompkins, United States of AmericaTakeoff (climb)

On August 24, 2001, a Learjet 25 (registration N153TW) operated by Ameristar Jet Charter was involved in an aviation accident near Ithaca-Tompkins, United States of America during takeoff. 2 people were killed. Investigators recorded the probable cause as: The pilot's failure to maintain a proper climb rate while taking off at night, which was a result of spatial disorientation. Factors in the accident were the low visibility and cloud conditions, and the dark night. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 3 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781202497Data APIEditorial standards

During departure in fog, an airplane struck a fence and impacted terrain beyond the runway. The official probable cause attributes the accident to spatial disorientation and low visibility.

Accident Overview

While departing from the airport, with the second-in-command (SIC) at the controls, the airplane impacted a fence and subsequently the ground about 1,000 feet beyond the departure end of the runway. The accident occurred during a period of fog and low visibility.

Witness Account

A witness located on the ramp area south of the runway reported hearing the engines spool up. Due to the fog, only the strobe lights of the airplane were visible. The witness observed the airplane rotate approximately 3,500 feet from the departure end of the runway and begin to climb at a steep angle. The airplane was lost from sight when it reached about 150 feet above ground level.

Weather and Cockpit Discussion

The reported weather at 0550 included calm winds, visibility of 1/2 statute miles in fog, an overcast cloud layer at 100 feet, and a temperature and dew point of 17 degrees Celsius. Excerpts from the cockpit voice recorder (CVR) transcript revealed that the flightcrew discussed the prevailing visibility at the airport on numerous occasions, indicating that it appeared to be less than one mile.

Wreckage Examination

Examination of the wreckage revealed no anomalies with the airframe or engines, suggesting no mechanical failure contributed to the accident.

Probable Cause

According to the official findings, the probable cause was the pilot's failure to maintain a proper climb rate while taking off at night, which was a result of spatial disorientation. Factors in the accident were the low visibility and cloud conditions, and the dark night. The FAA Instrument Flying Handbook describes how a rapid acceleration during takeoff can stimulate the otolith organs in a way similar to tilting the head backwards, creating the somatogravic illusion of being in a nose-up attitude, especially when visual references are lacking. This illusion can lead a disoriented pilot to push the aircraft into a nose-low or dive attitude.