Accident Air Tractor AT-401 N4538K,
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ASN Wikibase Occurrence # 131739
 
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Date:Tuesday 9 July 1991
Time:23:30 LT
Type:Silhouette image of generic AT3P model; specific model in this crash may look slightly different    
Air Tractor AT-401
Owner/operator:Frontier Ag Service
Registration: N4538K
MSN: 401-0770
Engine model:P&W R-1340
Fatalities:Fatalities: 0 / Occupants: 1
Aircraft damage: Destroyed
Category:Accident
Location:Calexico, CA -   United States of America
Phase: Initial climb
Nature:Agricultural
Departure airport:
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
THE INVESTIGATION REVEALED THAT DURING THE DAY ON JULY 9TH, WORKERS FROM THE IMPERIAL COUNTY IRRIGATION DISTRICT ERECTED A LARGE CAUTION SIGN ON THE DEPARTURE RUNWAY ABOUT ONE THIRD OF THE WAY FROM THE START. THAT NIGHT THE PILOT ARRIVED AT THE AIRPORT FOR HIS NIGHT SPRAY RUN AND HE WAS UNAWARE OF THE NEWLY PLACED SIGN. AFTER LOADING THE CHEMICALS TO BE SPRAYED ON BOARD THE AIRCRAFT, THE PILOT TOOK OFF AND THE AIRCRAFT STRUCK THE SIGN WITH THE LEFT SPRAY BOOM. THE BOOM WAS TORN LOOSE FROM THE STRUCTURE, HOWEVER, DID NOT SEPARATE TOTALLY AND BEGAN TO FLAP IN THE AIRSTREAM AS CHEMICALS POURED FROM THE HOPPER. THE PILOT TURNED THE AIRCRAFT TO RETURN TO THE AIRSTRIP AS HE REACHED FOR THE EMERGENCY SHUTOFF VALVE TO STOP THE FLOW OF CHEMICALS. AS THE AIRCRAFT NEARED THE AIRSTRIP, IT COLLIDED WITH A STACK OF HAY BALES RECENTLY ERECTED NEAR THE RUNWAY.

Probable Cause: THE ERECTION OF A CONSTRUCTION SIGN ON AN ACTIVE RUNWAY BY COUNTY WORKERS WITHOUT NOTIFYING THE AIRPORT OPERATORS, AND, THE INABILITY OF THE PILOT TO DETECT THE PRESENCE OF THE SIGN DURING THE DARK NIGHT TAKEOFF.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: LAX91LA302
Status: Investigation completed
Duration: 1 year and 8 months
Download report: Final report

Sources:

NTSB LAX91LA302

Location

Revision history:

Date/timeContributorUpdates
21-Dec-2016 19:25 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
11-Apr-2024 14:04 ASN Update Bot Updated [Time, Other fatalities, Phase, Source, Narrative, Category, Accident report]

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