# NTSB LAX92LA108: Sikorsky S55B, N1033, Richvale, CA, February 4, 1992

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: February 4, 1992, 09:30 local (17:30 UTC)
- Place: Richvale, CA
- Coordinates: 39.480697, -121.839828 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4807&lon=-121.8398&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 uninjured; on the ground: 1 serious
- Status: Completed, report June 11, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27550
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX92LA108
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27550/pdf
- Page: https://openairdocs.org/ntsb/LAX92LA108

## Probable cause

THE FAILURE OF THE LATERAL CONTROL ARM IN THE CYCLIC CONTROL SYSTEM.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, standing - engine(s) operating
  - rotorcraft flight control,cyclic control rod - fractured (cause)
- Roll over, standing - engine(s) operating
  - aircraft control - not possible, pilot in command

## Analysis

AS THE HELICOPTER WAS BEING REFUELED IN PREPARATION FOR AN AERIAL APPLICATION FLIGHT, THE PILOT WAS IN THE HELICOPTER AND THE MAIN ROTOR BLADES WERE ROTATING AT 'FLIGHT RPM.'  ACCORDING TO THE PILOT, THE HELICOPTER SUDDENLY 'JUMPED ABOUT TWO FEET IN THE AIR AND AT THE SAME TIME ROLLED TO THE RIGHT AND MOVED FORWARD.'  THE MAIN ROTOR BLADES STRUCK THE FUEL TRUCK AND THE HELICOPTER ROLLED OVER.  AN EXAMINATION OF THE HELICOPTER'S STRUCTURE REVEALED THAT THE LATERAL CONTROL ARM COMPONENT IN THE CYCLIC CONTROL SYSTEM HAD FRACTURED AT A TAPER PIN HOLE. THEREAFTER, THE DISCONNECTED CYCLIC CONTROL SYSTEM PERMITTED THE MAIN ROTOR BLADES TO TILT DOWN, AND THE ROLL OVER WAS UNAVOIDABLE.  NO PRE-EXISTING DEFECT WAS REPORTED OBSERVED IN THE LATERAL CONTROL ARM WHEN THE HELICOPTER WAS PREVIOUSLY INSPECTED, ABOUT 14 OPERATIONAL HOURS PRIOR TO THE ACCIDENT.

## Aircraft

- Registration: [N1033](https://openairdocs.org/deregistered/N1033-2013-09-16), registration cancelled 2013-09-16, S/N 1328, built 1967 (OpenAirDocs)
- Reported make and model: SIKORSKY S55B
- Registry model: [Sikorsky H-19G](https://openairdocs.org/model/sikorsky-h-19g) (registry code 8141618) (OpenAirDocs)
- Registry engine: [Wright R-1300 series](https://openairdocs.org/engine/wright-r-1300-series) (registry code 67060, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1328
- Airframe hours: 5616
- Engines: CURTIS WRIGHT R-1300 800 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Avag Corporation
- Registered owner: Avag Corporation
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, October 10, 1991, 89 hours before
- Airport: O97, Richvale

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 63; airline transport, commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 22,020 total, 6,200 in this make and model, 20,500 as pilot in command, 120 in the last 90 days, 50 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 10 knots, gusting 10
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 57 °F
- Altimeter: 30.00 inHg

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19920204001839A](https://openairdocs.org/incident/19920204001839A), Feb 4, 1992: Skrsky S55B, Richvale, CA, Substantial damage. On ground rotors at flight RPM. Helicopter jumped,rolled,hit fuel truck. Pinned fueler. Cyclic control arm broke.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.