Sikorsky S-58ET accident near Rancho P.Verdes, California, July 12, 2003
On July 12, 2003 at about 5:28 pm local time, a Sikorsky S-58ET (helicopter), registered N15AH, was destroyed in an accident near Rancho P.Verdes, California. It was an other work-use flight under external-load helicopter rules (Part 133). 1 person was seriously injured. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A total loss of antitorque control, due to the fatigue-induced failure of a gear within the drive shaft's intermediate gear box (IGB). Contributing factors were the pilot's improper on-ground decision to continue flight operations following discovery of material on the IGB's chip plug, and his failure to immediately jettison the external load.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 12, 2003 · about 5:28 pm local time
- Place
- Rancho P.Verdes, California · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S-58ET · all S-58ETs on the register
- Registration
- N15AH · registry record · serial 58-1563
- Damage
- Destroyed
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
The helicopter experienced a loss of tail rotor drive while maneuvering during a Federal Aviation Administration authorized low altitude external long line host operation, and collided with the ground in the subsequent descent. At the time, the operation was being performed in an area of the height-velocity curve that did not allow for a successful autorotative landing. Witnesses reported that minutes prior to the accident the pilot had made a precautionary landing due to illumination of the intermediate gearbox (IGB) chip light. The pilot removed, inspected, and cleaned the chip plug that contained metallic-like particles. During this action, the pilot was overheard to express concern to a ground crewmember by stating "this can be a problem." The pilot elected to continue flight operations. About 13 minutes later, within 200 feet above ground level while lifting an air conditioner (AC) unit from a school building, the pinion gear (part number S1635-64114-101) going into the drive side of the helicopter's intermediate gearbox (IGB) failed. This resulted in a total loss of antitorque control, and the helicopter yawed and spun in a clockwise direction while descending, and the helicopter impacted the unoccupied schoolyard. The pinion gear for the intermediate gearbox was examined. The laboratory reported that the initiating failure event had resulted from a fatigued gear tooth. The failure occurred about 175 hours prior to the part reaching its 2,000-hour life limit. The external long line was still connected to the cargo hook. Examination of the cockpit disclosed that the electrical cargo release switch was not armed. Post accident tests established that both the electrical release and manual backup cargo release mechanisms functioned.
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
Pilot
- Certificate: airline transport pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 14,500 hours in all; 1,500 in this make and model; 100 in the last 90 days; 40 in the last 30 days; 14,300 as pilot in command; 500 on instruments
- Last flight review: December 1, 2002
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 7,879 hours
- Last inspection: 100-hour inspection, June 1, 2003; 11 hours since
- Maximum gross weight: 13,000 lb
- Seats: 11
- Landing gear: fixed
- Engine: Pratt & Whitney PT6T-6 (turboshaft); 0 hours total
The flight
- Departed from: Rancho P.Verdes CA at 5:15 pm
- Destination: Rancho P.Verdes CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: at 5 knots
- Visibility: 4 statute miles
- Sky: broken clouds at 15,000 ft; a few clouds
- Temperature: 73°F (23°C), dew point 64°F (18°C)
- Altimeter: 30.04 inHg
- Observation at 4:57 pm from TOA, 3 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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 LAX03FA232.