Bell OH-58A accident near Brawley, California, November 21, 2023
On November 21, 2023 at about 4:05 am local time, a 1971 Bell OH-58A (helicopter), registered N158TR, was substantially damaged in an accident during initial climb near Brawley, California (Brawley Municipal airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A total loss of engine power due to the failure of the No. 8 bearing and the subsequent failure of the scavenge oil pump.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 21, 2023 · about 4:05 am local time
- Place
- Brawley, California · Brawley Municipal · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell OH-58A, built 1971 · all OH-58As on the register
- Registration
- N158TR · registry record · serial 71-20791
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot was conducting agricultural operations at night and had just departed from a company loading area. About 150 ft above ground level (agl), the pilot experienced a sudden power surge, abnormal engine noise, and vibration. The pilot believed that engine failure was imminent and turned back toward his point of departure. Engine power decayed, and the pilot bled off rotor rpm to maneuver over terrain toward flat ground. The helicopter landed hard, entered a pylon whirl condition, and the main rotor hub assembly separated from the main rotor mast. Postaccident examination of the airframe revealed no evidence of preaccident mechanical malfunction or failure. However, postaccident examination revealed a sheen of oil beneath the engine and that the engine’s compressor (N1) and power turbine (N2) systems were seized. Further examination of the engine revealed multiple failed bearings, failed drives, and fractures within the turbine scavenge oil pump assembly. The engine had been installed on the helicopter about 10 flight hours before the accident. Based on metallurgical analysis of the engine components, the No. 8 bearing likely failed and shed debris to the oil pump, which bound the first level oil pump gears and led a gear tooth to fracture and the pump driveshaft to fail. Subsequently, the engine was starved of oil and lost all power. The cause of the bearing failure could not be determined.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Hard landing during landing
- Loss of engine power (total) during initial climb defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Oil system › Failure
- Aircraft › Aircraft oper/perf/capability › Aircraft capability › (general) › Capability exceeded
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 13,255 hours in all; 2,750 in this make and model; 138 in the last 90 days; 46 in the last 30 days; 13,180 as pilot in command; 225 on instruments
- Last flight review: June 29, 2023
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 9,911.1 hours
- Last inspection: 100-hour inspection, November 7, 2023; 10.3 hours since
- Maximum gross weight: 3,000 lb
- Seats: 4
- Landing gear: fixed
- Engine: Rolls-Royce 250-C20B (turboshaft); 2,901 hours total
- Fire on the ground
The flight
- Flight plan: none
Weather at the time
- Light: night
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 28°F (-2°C)
- Altimeter: 30.22 inHg
- Observation at 7:53 pm from KIPL, 11 miles away
Weather report (METAR): METAR KIPL 210353Z AUTO 29004KT 10SM CLR 14/M02 A3022
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 1 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR24LA041.