# NTSB DEN91LA114: Air Tractor AT-502, N4535K, Clovis, NM, August 16, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 15, 1991, 19:41 local (Aug 16, 1991, 01:41 UTC)
- Place: Clovis, NM
- Coordinates: 34.410987, -103.199958 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.4110&lon=-103.2000&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 2, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18123
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN91LA114
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18123/pdf
- Page: https://openairdocs.org/ntsb/DEN91LA114

## Probable cause

FAILURE OF THE PILOT TO MAINTAIN CLEARANCE FROM RISING/UNEVEN TERRAIN.  FACTORS RELATED TO THE ACCIDENT WERE: THE LIGHT CONDITIONS AT DUSK, AND THE LACK OF VISUAL CUES FOR THE PILOT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight collision with terrain/water, maneuvering - aerial application
  - light condition - dusk (contributing factor)
  - terrain condition - rough/uneven (contributing factor)
  - clearance - not maintained, pilot in command (cause)
  - visual/aural perception, pilot in command (contributing factor)

## Analysis

THE PILOT WAS FLYING HIS LAST SWATH RUN OF THE DAY AT DUSK. HE SAID HE DIDN'T SEE A RISE IN THE TERRAIN AT THE END OF THE FIELD AND ALLOWED THE AIRCRAFT TO STRIKE A DIRT BERM. THE AIRCRAFT ENGINE IMMEDIATELY CAUGHT FIRE. HE DUMPED HIS LOAD OF FERTILIZER/FUNGICIDES AND LANDED THE AIRCRAFT. THE FIRE DESTROYED THE AIRCRAFT.

## Aircraft

- Registration: [N4535K](https://openairdocs.org/deregistered/N4535K-1998-10-01), registration cancelled 1998-10-01, S/N 5020104 (OpenAirDocs)
- Reported make and model: AIR TRACTOR AT-502
- Registry model: [Air Tractor AT-502](https://openairdocs.org/model/air-tractor-at-502) (registry code 0390303) (OpenAirDocs)
- Category: Airplane
- Serial number: 502-0104
- Engines: P&W PT6A-34 750 horsepower turbo prop
- Damage: Destroyed
- Fire: On-Ground
- Flight: Aerial application, Part 137
- Operator: Gregory L. Kubin, doing business as Kubin Aerial, Inc.
- Registered owner: Gregory L. Kubin
- Departed: Q34, PORTALES, NM

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; flight hours: 6,700 total, 560 in this make and model

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 135° at 2 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19910815034569A](https://openairdocs.org/incident/19910815034569A), Aug 15, 1991: Airtrc AT502, Clovis, NM, Destroyed. Struck a dirt berm on a spray run. Impact caused engine fire. Dumped load,landed and aircraft destroyed by fire.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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