Accident Ayres S-2R-T34 Turbo Thrush N4017B, Wednesday 26 September 1990
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Date:Wednesday 26 September 1990
Time:09:14
Type:Silhouette image of generic SS2T model; specific model in this crash may look slightly different    
Ayres S-2R-T34 Turbo Thrush
Owner/operator:George Clanton Dusting Sprayin
Registration: N4017B
MSN: T34-002
Total airframe hrs:5592 hours
Engine model:P&W PT6A-34AG
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Destroyed
Category:Accident
Location:Thornton, MS -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Agricultural
Departure airport:Yazoo City, MS (87I)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
AIRPLANE EXPERIENCED SEPARATION OF RIGHT WING WHILE PULLING UP FROM AGRICULTURAL SPRAYING RUN. WING SEPARATED DUE TO FATIGUE FAILURE OF THE BOTTOM SPAR CAP WHICH WAS THE RESULT OF A HOLE BEING DRILLED INTO THE CAP. THE HOLE APPEARS TO HAVE BEEN DRILLED INTO THE CAP DURING INSTALLATION OF A WING MOUNTED AIR CONDITIONING COMPRESSOR, SIX YEARS AND 4,130 FLIGHT HOURS BEFORE THE FAILURE. THE AIR CONDITIONING UNIT WAS REMOVED 10 MONTHS LATER AND A PATCH WAS PLACED OVER THE AREA THE HOLE HAD BEEN DRILLED IN SPAR CAP. THE HOLE WOULD NOT HAVE BEEN VISIBLE DURING INSPECTION UNLESS MECHANIC REMOVED PATCH. CAUSE: THE IMPROPER DRILLING OF A HOLE IN THE SPAR CAP BY A MECHANIC RESULTING IN THE INITIATION OF FATIGUE CRACKING IN THE SPAR CAP AND SUBSEQUENT FAILURE OF THE SPAR CAP AND INFLIGHT SEPARATION OF THE WING.

Sources:

NTSB: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001212X24323

Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency, ]

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