Arrow Falcon Exporters INC OH-58C accident near Brentwood, California, July 3, 2011
On July 3, 2011 at about 1:30 pm local time, a Arrow Falcon Exporters INC OH-58C (helicopter), registered N6264D, was substantially damaged in an accident during maneuvering (low-alt flying) near Brentwood, California. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The failure of the main rotor mast due to fatigue cracking originating from corrosion pits.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 3, 2011 · about 1:30 pm local time
- Place
- Brentwood, California · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Arrow Falcon Exporters INC OH-58C · all OH-58Cs on the register
- Registration
- N6264D · no longer on the register · serial 69-16118
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
During an aerial application flight, the helicopter's main rotor mast separated, and the helicopter fell from a height of about 30 feet and impacted terrain. Postaccident examination of the wreckage found that the mast had fractured below the point where it extended from the transmission and just above the mast seal retainer plate. Examination of the fracture surfaces revealed that an area of fatigue extended about 95 degrees around the mast’s circumference. The remaining portions of the fracture were identified as low cycle fatigue and overload. The fracture had multiple origins at corrosion pitting on the threads of the mast. The source of the corrosion could not be determined. Maintenance records indicated that the most recent overhaul of the main rotor mast assembly was completed 1,486 hours before the accident. At that time, a magnaflux inspection was performed on the main rotor mast with no discrepancies noted. The records indicate that, during reassembly, a sealant was applied to the threads for corrosion protection. When the mast is installed on the helicopter, the location where the corrosion and fracture occurred is hidden. To fully inspect the area, the mast assembly must be removed from the helicopter and completely disassembled. A second mast failure on a helicopter of the same make and model series occurred on January 20, 2012, in Brawley, California (WPR12LA096). In February 2012, the helicopter manufacturer issued an alert service bulletin that reduced the main rotor mast overhaul interval from 2,400 hours to 1,200 hours. In July 2012, the Federal Aviation Administration issued Airworthiness Directive (AD) 2012-14-11, applicable to Arrow Falcon Exporters, Rotorcraft Development Corporation, and San Joaquin Helicopters model OH-58A, OH-58A+, and OH-58C helicopters. The AD required, within 30 days, overhaul of the main rotor mast assemblies of these helicopters.
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
- Sys/Comp malf/fail (non-power) during maneuvering (low-alt flying) defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor mast/swashplate › Failure
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor mast/swashplate › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 9,978 hours in all; 2,314 in this make and model
- Last flight review: May 6, 2010
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 5,030 hours
- Last inspection: annual inspection, December 2, 2010
- Seats: 4
- Landing gear: fixed
- Engine: Allison T63-A-720 (turboshaft); 0 hours total
The flight
- Departed from: Brentwood CA at 1:10 pm
- Destination: Brentwood CA
- Flight plan: not recorded
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 54°F (12°C)
- Altimeter: 29.76 inHg
- Observation at 1:53 pm from LVK, 17 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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 documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text 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 WPR11LA303.