Arrow Falcon Exporters, Inc. OH-58A accident near Brawley, California, January 21, 2012
On January 21, 2012 at about 3:00 am local time, a Arrow Falcon Exporters, Inc. OH-58A (helicopter), registered N902SF, was substantially damaged in an accident during takeoff near Brawley, California. 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).
The NTSB's probable cause their words, unchanged
The failure of the main rotor mast due to fatigue cracks that originated from corrosion pits. Contributing to the accident was the operator’s failure to adhere to the manufacturer’s recommended overhaul interval for the main rotor mast.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 21, 2012 · about 3:00 am local time
- Place
- Brawley, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Arrow Falcon Exporters, Inc. OH-58A
- Registration
- N902SF · no longer on the register · serial 70-15406
- 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 takeoff, the pilot pulled up on the collective, and the main rotor mast fractured near the point where it extends from the transmission; the pilot then aborted the takeoff. The fracture was located below the threads for the mast nut and above the bearing journal for the upper mast bearing. Postaccident examination of the fracture surface revealed multiple fatigue cracks that initiated at the outer diameter of the mast and extended through about 50 percent of the mast's cross section. The fatigue initiation areas and the through-the-wall portion of the fatigue were heavily corroded with extensive pitting and dark deposits visible. A dark oily material was found on the mast's outer surface near the fracture, and the mast's surface was severely corroded on both sides of the fracture. Analysis of samples of the dark oily material suggests that it was a mixture of lubricating oil and water. 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. Maintenance records indicated that the most recent overhaul of the main rotor mast was completed 2,499 hours before the accident, about 99 hours beyond the helicopter manufacturer's recommended time between overhaul of 2,400 hours. The NTSB has previously investigated a similar main rotor mast failure on the same make and model helicopter; in that case, the most recent overhaul of the main rotor mast was completed 1,486 hours before the accident. As a result of these events, in February 2012, the manufacturer issued an alert service bulletin that reduced the main rotor mast overhaul interval from 2,400 hours to 1,200 hours. Additionally, 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 requires operators of those helicopters to, within 30 days, overhaul the helicopters’ main rotor mast assemblies.
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 takeoff defining event
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
- factor Aircraft › Aircraft propeller/rotor › (general) › (general) › Incorrect service/maintenance
Pilot
- Certificate: commercial pilot, private
- Ratings: multi-engine land; single-engine land; rotorcraft: helicopter
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Seats: 4
- Landing gear: fixed
- Engine: Allison 250 C20 (turboshaft); 0 hours total
- Operator: Farm Aviation INC
The flight
- Departed from: Brawley CA at 3:00 am
- Destination: Brawley CA
- Flight plan: none
Weather at the time
- Light: night
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 59°F (15°C), dew point 34°F (1°C)
- Altimeter: 29.97 inHg
- Observation at 2:53 am from IPL, 10 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.
Other NTSB records under N902SF the same tail number, which may have belonged to a different aircraft at the time
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.