- Date
- July 9, 1991, 23:30 local (Jul 10, 1991, 06:30 UTC)
- Place
- Calexico, CA
- Injuries
- 1 minor
- Damage
- Destroyed
- Phase of flight
- Initial climb
- Aircraft
- N4538KAir Tractor AT-401
- Weather
- Visual (VMC) · Night/dark
- Status
- Completed · report March 31, 1993
- Report
- Approved by Office Director
- FAA report
- 19910709026639A
- Case key
- 27282
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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.
Aircraft
- Registration
- N4538K
- Reported as
- Air Tractor AT-401
- Category
- Airplane
- Serial number
- 401-0770
- Engine
- P&W R-1340, 600 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Aerial application · Part 137
- Operator
- Frontier Ag Service
- Registered owner
- Frontier Ag Service
- Last inspection
- Unknown · January 2, 2000
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 55
- Certificate
- Commercial
- Airplane ratings
- Single-engine land, Multi-engine land
- Medical
- Class 2, Valid Medical--w/ waivers/lim
- Flight hours
- 8,100 total · 1,400 in this make and model · 160 in the last 90 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Night/dark
- Wind
- 250° at 6 knots
- Visibility
- 30 statute miles
- Lowest ceiling
- None
- Temperature
- 81 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.