Final Report: Disoriented in fog, pilot crashed Learjet 25 on takeoff

 - August 5, 2008, 8:45 AM

LEARJET 25, ITHACA, N.Y., AUG. 24, 2001–The NTSB determined the probable cause of this accident to be the pilot’s failure to maintain a proper climb rate while taking off at night, resulting in spatial disorientation. Additional factors included low visibility and cloud conditions, and the dark night.

At about 5:42 a.m. EDT Learjet N153TW, operated by Ameristar Jet Charter, was destroyed when it crashed on departure from Ithaca Tompkins County Airport. Both the ATP-rated pilot and commercial-rated copilot were killed. There were no passengers on board the aircraft for the Part 135 on-demand cargo flight destined for Jackson, Mich. Night IMC existed at the time of the accident, and the aircraft was on an IFR flight plan.

While departing from the airport, with the second-in-command pilot at the controls, the airplane hit a fence, and subsequently the ground about 1,000 feet beyond the departure end of the runway. A witness on the ramp area south of the runway stated that he heard the engines spool up; however, due to the fog he could see only the strobe lights of the airplane. He then observed the airplane rotate about 3,500 feet from the departure end of the runway and begin to climb at a steep angle, before losing sight of it when it was about 150 agl.

The reported weather, at 0550 was calm; half a mile visibility in fog; overcast cloud layer at 100 feet; and temperature and dew point matched at 17 degrees C. Excerpts of the cockpit voice recorder (CVR) transcript revealed that the flight crew discussed the prevailing visibility at the airport on numerous occasions, and indicated that it appeared to be less than one mile.

Both pilots were current and qualified to operate the aircraft, according to FAA regulations, and examination of the wreckage revealed no anomalies with the airframe or engines.

According to the FAA Instrument Flying Handbook, “Flying in instrument meteorological conditions can result in sensations that are misleading to the body’s sensory system…A rapid acceleration, such as experienced during takeoff, stimulates the otolith organs in the same way as tilting the head backwards. This action creates the somatogravic illusion of being in a nose-up attitude, especially in situations without good visual references. The disoriented pilot may push the aircraft into a nose-low or dive attitude.”