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Accident description
Last updated: 11 December 2017
Status:Final
Date:Thursday 18 January 1990
Time:17:10
Type:Silhouette image of generic LJ23 model; specific model in this crash may look slightly different
Learjet 23
Operator:Aero Flight Services
Registration: N331DP
C/n / msn: 23-067
First flight: 1965
Total airframe hrs:5600
Engines: 2 General Electric CJ610-4
Crew:Fatalities: 2 / Occupants: 2
Passengers:Fatalities: 0 / Occupants: 0
Total:Fatalities: 2 / Occupants: 2
Airplane damage: Destroyed
Airplane fate: Written off (damaged beyond repair)
Location:Ansonia, OH (   United States of America)
Phase: En route (ENR)
Nature:Ferry/positioning
Departure airport:Detroit-Willow Run Airport, MI (YIP/KYIP), United States of America
Destination airport:Louisville-Standiford Field, KY (SDF/KSDF), United States of America
Narrative:
The Learjet 23, N331DP, was cleared for takeoff on a flight from Detroit-Willow Run Airport, MI (YIP) to Louisville-Standiford Field, KY (SDF). At 05:32, about 17 minutes into the flight, the flight crew began to display indications of a deterioration of their ability to control the aircraft. At first, they deviated from instructions to hold west of the Findlay VOR at FL220. As the flight continued and was cleared to FL270, the crew displayed confusion about magnetic headings and basic instruments. At 05:48, the aircraft deviated from the en route heading and the wrong heading was read back after a heading correction was given. Also, the aircraft continued climbing (to FL291), then radar and radio contact were lost at 05:51. The controller noted the pilot's speech was slurred and some portions of the conversation were unintelligible. Subsequently, the aircraft crashed in a steep dive. No preimpact part failure was verified, though impact forces and post-crash fire resulted in extensive damage of the aircraft. The aircraft was equipped with oxygen and pressurization systems. No audible warning was noted on ATC recordings to indicate the cabin altitude had exceeded 10,000 feet, though the aircraft was equipped with such a device.

Probable Cause:

PROBABLE CAUSE: "The flight crew became incapacitated for undetermined reasons and lost control of the airplane. "

Accident investigation:
cover
Investigating agency: NTSB
Status: Investigation completed
Duration: 3 years and 2 months
Accident number: ATL90MA051
Download report: Summary report

Classification:
Flightcrew incapacitation
Loss of control

Sources:
» NTSB


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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Detroit-Willow Run Airport, MI to Louisville-Standiford Field, KY as the crow flies is 486 km (304 miles).
Accident location: Approximate; accuracy within a few kilometers.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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