Accident Learjet 23 N331DP, Thursday 18 January 1990
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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
Owner/operator:Aero Flight Services
Registration: N331DP
MSN: 23-067
Year of manufacture:1965
Total airframe hrs:5600 hours
Engine model:General Electric CJ610-4
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Destroyed, written off
Category:Accident
Location:Ansonia, OH -   United States of America
Phase: En route
Nature:Ferry/positioning
Departure airport:Detroit-Willow Run Airport, MI (YIP/KYIP)
Destination airport:Louisville-Standiford Field, KY (SDF/KSDF)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
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: "The flight crew became incapacitated for undetermined reasons and lost control of the airplane. "

Accident investigation:
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Investigating agency: NTSB
Report number: ATL90MA051
Status: Investigation completed
Duration: 3 years 1 month
Download report: Final report

Sources:

NTSB

Location

Revision history:

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