# NTSB LAX89FA160: Sikorsky S-58ET, N1168U, Santa Ana, CA, April 15, 1989

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Field investigation · Final report
- Date: April 14, 1989, 18:33 local (Apr 15, 1989, 01:33 UTC)
- Place: Santa Ana, CA
- Coordinates: 33.670063, -117.900192 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.6701&lon=-117.9002&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report June 22, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26222
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX89FA160
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26222/pdf
- Page: https://openairdocs.org/ntsb/LAX89FA160

## Probable cause

FAILURE OF THE LANDING GEAR RESULTING FROM EXCESSIVE LOADING DURING GROUND OPERATIONS, AND FATIGUE CRACKING.

## Sequence of events

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

- Main gear collapsed, taxi - to takeoff
  - landing gear,main gear strut - overload (cause)
  - aircraft weight and balance - exceeded, pilot in command (cause)
  - landing gear,main gear strut - fatigue (cause)
  - landing gear,main gear strut - corroded
- Roll over, taxi - to takeoff

## Analysis

AFTER THE CARGO WAS LOADED, AND AS THE PILOT GROUND TAXIED OVER A CONCRETE DRAINAGE DEPRESSION IN THE RAMP, THE LEFT MAIN LANDING GEAR SEPARATED FROM THE GEAR TUBE AND THE HELICOPTER ROLLED OVER. METALLURGICAL EXAMINATION OF THE FAILED LANDING GEAR STRUT REVEALED PRE-EXISTING FATIGUE CRACKS IN THE INSIDE THE GEAR LEG EXTENDING FROM MULTIPLE ORIGINS. IN ADDITION, THERE WAS CORROSION PITTING AND REMNANT TOOLING MARKS ON THE SURFACE FINISH OF THE LOWER GEAR TUBE INSIDE DIAMETER. THE PITTED AND CORRODED CONDITION OF THE TUBE INSIDE DIAMETER INDICATED THAT ENVIRONMENTAL INTRUSION OF THE CORROSION PREVENTATIVE MATERIAL MAY HAVE OCCURRED DURING SERVICE. THE AIRCRAFT WAS 951 POUNDS OVER CERTIFICATED MAXIMUM GROSS WEIGHT.

## Aircraft

- Registration: [N1168U](https://openairdocs.org/aircraft/N1168U), registered now, S/N 58-1070, built 1958 (OpenAirDocs)
- Reported make and model: SIKORSKY S-58ET
- Registry model: [Sikorsky S-58ET](https://openairdocs.org/model/sikorsky-s-58et) (registry code 8141803) (OpenAirDocs)
- Registry engine: [Pratt & Whitney Canada PT6T-6](https://openairdocs.org/engine/pratt-whitney-canada-pt6t-6) (registry code 52106, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 58-1070
- Airframe hours: 15715
- Engines: P&W PT6T-6 825 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Aris Helicopters, Ltd
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, April 14, 1989
- Departed: SNA
- Destination: LAX, LOS ANGELES, CA
- Flight plan: Company VFR
- Airport: SNA, John Wayne

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; commercial, military; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 3,653 total, 128 in this make and model, 3,473 as pilot in command, 20 in the last 90 days, 11 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 12 knots
- Visibility: 5 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 63 °F, dew point 55 °F
- Altimeter: 30.00 inHg
- Observed at: SNA

## 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 19890414007979A](https://openairdocs.org/incident/19890414007979A), Apr 14, 1989: Skrsky S58ET, Santa Ana, CA, Substantial damage. Taxied over a ramp depression, helicopter entered ground resonance, left gear broke due corrosion and overload.

## Other investigations on N1168U (1)

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.

- [NTSB WPR19LA255](https://openairdocs.org/ntsb/WPR19LA255), Sep 11, 2019: Sikorsky S58 (N1168U), Azusa, CA, substantial damage. Probable cause: The in-flight separation of a section of the tail rotor blade due to a fatigue crack, which resulted in the pilot’s forced autorotation into a field.

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.