# NTSB LAX98LA144: Schweizer G164D, N31785, Robbins, CA, April 27, 1998

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: April 27, 1998, 07:15 local (14:15 UTC)
- Place: Robbins, CA
- Location: 38.8669° N, 121.7071° W: Placed by OpenAirDocs: center of Robbins, CA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=38.8669&lon=-121.7071&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report June 21, 2000
- Report: Approved by Office Director
- NTSB case key (mKey): 30075
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX98LA144
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/30075/pdf
- Page: https://openairdocs.org/ntsb/LAX98LA144

## Probable cause

Aircraft rudder post failure due to extensive rusting which resulted in a partial loss of aircraft control.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - flt control syst,rudder control attach points - corroded (contributing factor)
  - flt control syst,rudder control attach points - sheared (cause)
- Loss of control - in flight, maneuvering - aerial application
  - aircraft control - diminished, pilot in command (contributing factor)
- Dragged wing,rotor,pod,float or tail/skid, maneuvering - aerial application
  - terrain condition - open field (contributing factor)

## Analysis

During a low altitude aerial application run, the aircraft rudder post broke resulting in a partial loss of flight control.  The airplane then drug a wing tip and cartwheeled into the ground.  During a postflight inspection of the rudder assembly, it was noted that the rudder post was extensively oxidized (rusted) in the area of the break point. There were also rust deposits on approximately 1/3 of the circumference of the parting surfaces.

## Factual narrative

On April 27, 1998, at 0715 hours Pacific daylight time, a Schweizer G164D, N31785, was destroyed when it impacted terrain near Robbins, California.  The solo commercial pilot sustained minor injuries and no property damage was incurred.  The flight had departed Tolle's Flying Service southwest of Robbins on an aerial application flight, and was being operated by Tolle's Flying Service, Inc.  Visual meteorological conditions prevailed and no flight plan had been filed.  The pilot stated that the rudder post broke on his first application run.  This resulted in loss of flight control which caused the airplane to drag a wing tip and cartwheel into the ground.

During a postflight inspection of the rudder assembly, it was noted that the rudder post was extensively oxidized (rusted) in the area of the break point.  There were also rust deposits on approximately 1/3 of the circumference of the parting surfaces.

## Aircraft

- Registration: [N31785](https://openairdocs.org/deregistered/N31785-2000-05-08), registration cancelled 2000-05-08, S/N 9D (OpenAirDocs)
- Reported make and model: Schweizer G164D
- Registry model: [Schweizer G-164D](https://openairdocs.org/model/schweizer-g-164d) (registry code 8059059) (OpenAirDocs)
- Category: Airplane
- Serial number: 9D
- Airframe hours: 5906
- Engines: P&W PT6=34 750 horsepower turbo prop
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Registered owner: Tolle'S Flying Service
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, December 1, 1997, 264 hours before
- Departed: NONE, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 53; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 36,700 total, 18,100 in this make and model, 36,650 as pilot in command, 200 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 48 °F
- Altimeter: 30.00 inHg
- Observed at: SAC, 18 nm away

## 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 19980427007839A](https://openairdocs.org/incident/19980427007839A), Apr 27, 1998: Scwzer G164D, Robbins, CA, Destroyed. During a low altitude aerial application run, the aircraft rudder post broke resulting in a partial loss of flight control. The airplane then drug a wing tip…

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.

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