# NTSB LAX92LA038: Questaire Venture, N71T, San Luis Obispo, CA, November 2, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 2, 1991, 10:00 local (18:00 UTC)
- Place: San Luis Obispo, CA
- Coordinates: 35.250274, -120.620811 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2503&lon=-120.6208&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report April 27, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27497
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX92LA038
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27497/pdf
- Page: https://openairdocs.org/ntsb/LAX92LA038

## Probable cause

THE PILOT'S INABILITY TO CONTROL THE AIRCRAFT DURING THE LANDING ROLL DUE TO A FAILURE OF THE LEFT BRAKE AND NOSE WHEEL STEERING SYSTEMS.  THE FAILURE OF THE BRAKE AND STEERING SYSTEMS WAS DUE TO A DETERIORATION OF THE 'O' RING SEALS CAUSED BY THE USE OF HYDRAULIC FLUID INCOMPATIBLE WITH THE RUBBER MATERIAL IN THE SEALS.  A FACTOR IN THE ACCIDENT WAS THE INADEQUATE SYSTEM DESIGN BY THE KIT MANUFACTURER.

## Sequence of events

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

- Airframe/component/system failure/malfunction, landing - roll
  - fluid,hydraulic - incorrect (cause)
  - insufficient standards/requirements,manufacturer, manufacturer (contributing factor)
  - hydraulic system,seal - deteriorated (cause)
  - landing gear,normal brake system - failure,partial
  - landing gear,steering system - failure,total
- Loss of control - on ground/water, landing - roll
  - directional control - not possible, pilot in command
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - rough/uneven
- Nose gear collapsed, landing - roll
  - landing gear,nose gear attach point - overload

## Analysis

ON THE LANDING ROLL OUT, THE AIRCRAFT BEGAN A GRADUAL RIGHT TURN WHICH THE PILOT WAS UNABLE TO CORRECT DUE TO A FAILURE OF THE LEFT BRAKE AND NOSE WHEEL STEERING SYSTEMS. THE AIRCRAFT EXITED THE RIGHT SIDE OF THE RUNWAY AND THE NOSE GEAR FORK FAILED.  THE AIRCRAFT NOSED OVER.  THE AIRCRAFT WAS EXAMINED BY AN FAA AIRWORTHINESS INSPECTOR.  THE INSPECTOR NOTED THAT THE HYDRAULIC BRAKE AND NOSE WHEEL STEERING SYSTEMS WERE INTERCONNECTED.  THE 'O' RING SEALS IN THE BRAKE SYSTEM WERE FOUND TO BE BADLY DETERIORATED AND HE REPORTED THAT THE HYDRAULIC FLUID HAD LEAKED OUT.  THE KIT MANUFACTURER RECOMMENDS USING AN AUTOMOTIVE TYPE FLUID IN THE SYSTEM.  THE INSPECTOR STATED HIS OPINION THAT THE AUTOMOTIVE BRAKE FLUID WAS INCOMPATIBLE WITH THE 'O' RING MATERIAL.

## Aircraft

- Registration: [N71T](https://openairdocs.org/deregistered/N71T-2002-12-03), registration cancelled 2002-12-03, S/N 26, built 1991 (OpenAirDocs)
- Reported make and model: QUESTAIRE VENTURE
- Registry model: [Thomas Michael C QUESTAIR VENTURE](https://openairdocs.org/model/thomas-michael-c-questair-venture) (registry code 0561845) (OpenAirDocs)
- Registry engine: [Continental IO-550 series](https://openairdocs.org/engine/continental-io-550-series) (registry code 17042, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 26
- Airframe hours: 2
- Engines: CONTINENTAL IO-550D 280 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Michael C. Thomas
- Registered owner: Michael C. Thomas
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, January 30, 1991, 2 hours before
- Airport: SBP, Mcchesney Fld, runway 29, 4,799 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 1,300 total, 2 in this make and model, 5 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 63 °F

## Other investigations on N71T (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 LAX91LA107](https://openairdocs.org/ntsb/LAX91LA107), Feb 12, 1991: Questaire Venture (N71T), San Luis Obispo, CA, substantial damage. Probable cause: THE FAILURE OF THE FUEL SYSTEM VENT CHECK VALVE, WHICH RESULTED IN FUEL STARVATION TO THE AIRCRAFT'S ENGINE.

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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