Bell OH58A accident near Holtville, California, July 31, 2020
On July 31, 2020 at about 3:45 am local time, a Bell OH58A (helicopter), registered N901XV, was substantially damaged in an accident during maneuvering (low-alt flying) near Holtville, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The total loss of engine power due to the decoupling of the engine's turbine and compressor sections, which resulted from improper maintenance.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 31, 2020 · about 3:45 am local time
- Place
- Holtville, California · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell OH58A · all OH58As on the register
- Registration
- N901XV · registry record · serial 69-16273
- 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 performing agricultural operations in the helicopter. He made a normal takeoff and completed three passes over the field being sprayed. As he approached wires, the pilot maneuvered the helicopter into a climb and prepared to make a fourth pass. As he was completing a left turn back to the field, the engine experienced a total loss of power. He performed an autorotation, and during the touchdown, the helicopter collided with haystacks. Postaccident examination of the engine revealed extensive damage to the aft end of the compressor, the spur adapter gearshaft, and the compressor splined adapter. A material analysis revealed that the compressor splined adapter had failed in fatigue. The failure decoupled the turbine section from the compressor section resulting in the loss of engine power. The compressor splined adapter failed due to a misalignment of the engine's centerline shafting components that resulted from two separate improper maintenance actions. The first improper maintenance action was the installation of an incorrect number of shims at the interface between the rear compressor diffuser and the accessory gearbox. The second improper maintenance action was the installation of an incorrect compressor splined adapter; the impeller had been machined to fit a larger diameter (-3) compressor splined adapter: however, a smaller diameter (-1) adapter was installed.
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
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Incorrect service/maintenance
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Failure
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 18,000 hours in all; 9,000 in this make and model; 105 in the last 90 days
- Last flight review: September 26, 2019
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 7,299 hours
- Last inspection: 100-hour inspection, July 8, 2020; 30 hours since
- Maximum gross weight: 3,200 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rolls Royce 250-C20C (turboshaft); 3,646 hours total
- Operator: A Farmer Service Corp.
The flight
- Departed from: IPL Imperial CA at 3:30 am
- Destination: IPL Imperial CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 230° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 104°F (40°C), dew point 52°F (11°C)
- Altimeter: 29.68 inHg
- Observation at 3:53 am from KIPL, 16 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on January 24, 2023. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 7 pages | View Download |
| 2 | Investigation Support Material Supplement | PDF, 5 pages | View Download |
| 3 | Rolls Royce Engine Examination Report | PDF, 5 pages | View Download |
| 4 | Statement of Party Representatives to NTSB Investigation | PDF, 1 page | View Download |
| 5 | Statement of Party Representatives to NTSB Investigation - Rolls Royce | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.