Accident Learjet 23 N5DM, Friday 11 June 1982
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Date:Friday 11 June 1982
Time:18:32 LT
Type:Silhouette image of generic LJ23 model; specific model in this crash may look slightly different    
Learjet 23
Owner/operator:Private
Registration: N5DM
MSN: 23-028
Total airframe hrs:5164 hours
Engine model:GE CJ610
Fatalities:Fatalities: 0 / Occupants: 8
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Abilene, TX -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Private
Departure airport:Dallas, TX (KDAL)
Destination airport:Abilene, TX (KABI)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
ABOUT 5 MIN AFTER TAKEOFF, THE PILOT INITIATED A HIGH SPEED LOW PASS OVER THE AIRPORT. WHEN THE AIRCRAFT WAS ABOUT 1000 FT FROM THE AIRPORT AT ABOUT 100 FT AGL, THE RICHT WINGLET SEPARATED. A WITNESS ESTIMATED THAT THE AIRCRAFT'S SPEED WAS ABOUT 200 MPH. SUBSEQUENTLY, THE PLANE ROLLED INVERTED AND CRASHED. AN EXAMINATION REVEALED THAT THE WINGLET WAS NOT INSTALLED IN ACCORDANCE TO THE DESIGNER'S PLANS. SPECIFICALLY, THE PLANS CALLED FOR AN 8-PLY FIBERGLASS BUILD-UP ON THE OUTSIDE RADIUS FROM THE LOWER WING TO THE OUTSIDE SURFACE OF THE WINGLET. THIS BUILD-UP WAS NOT INCORPORTED. THE DESIGNER ESTIMATED THAT IT HAD LESS THAN 1/20 OF THE DESIGN STRENGTH. AT HIGH SPEED, WITH ZERO SIDE SLIP, THERE IS AN INWARD AERODYNAMIC (BENDING) LOAD ON THE WINGLET THAT IS EQUIVALENT TO A 15 DEG SIDE SLIP AT LOW SPEED. THIS WINGLET HAD FAILED INWARD. ALSO, A NUMBER OF OTHER DEVIATIONS FROM THE DESIGNERS PLANS WERE NOTED.

Probable Cause:

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: FTW82FPD14
Status: Investigation completed
Duration: 1 year
Download report: Final report

Sources:

NTSB FTW82FPD14

Revision history:

Date/timeContributorUpdates
03-Apr-2024 08:27 ASN Update Bot Added

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