# NTSB CHI91MA260: British Aerospace 3201, N339TE, St Louis, MO, August 12, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Major investigation · Final report
- Date: August 12, 1991, 11:09 local (16:09 UTC)
- Place: St Louis, MO
- Location: 38.7487° N, 90.3700° W: Placed by OpenAirDocs at ST LOUIS LAMBERT INTL (STL), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=38.7487&lon=-90.3700&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 7 uninjured
- Status: Completed, report March 2, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15197
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91MA260
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15197/pdf
- Page: https://openairdocs.org/ntsb/CHI91MA260

## Probable cause

FAILURE OF THE PILOT(S) TO FOLLOW THE CORRECT EMERGENCY PROCEDURE.  FACTORS RELATED TO THIS ACCIDENT WERE: INADEQUATE SYSTEM DESIGN BY THE MANUFACTURER, WHICH ALLOWED HYDRAULIC LINE VIBRATION, FATIGUE FAILURE OF THE LINE, AND LOSS OF FLUID FROM THE NORMAL HYDRAULIC SYSTEM.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - hydraulic system,line - fatigue (contributing factor)
  - acft/equip,inadequate design, manufacturer (contributing factor)
  - fluid,hydraulic - leak (contributing factor)
  - landing gear,normal retraction/extension assembly - inoperative
- Gear not extended, landing - flare/touchdown
  - emergency procedure - not followed, pilot in command (cause)

## Analysis

DRG FLT, A HYDR LINE (PN 137311D1443) IN THE MAIN HYDR SYS FAILED. THE CAPT & 1ST OFFICER MADE NUMEROUS ATMTS TO EXTD THE LNDG GEAR BY USING THE EMERG CHECKLIST & ACFT FLT MANUAL. TWO OF 3 LNDG GEAR LEGS WERE EXTDD, BUT THE PLTS WERE UNABLE TO EXTD THE LEFT MAIN LNDG GEAR. SUBSEQENTLY, THE ACFT WAS DMGD DRG LNDG. THE HYDR LINE WAS CURVED & MEASURED ABT 15' FM END TO END. IT HAD FAILED AT THE BASE OF A FLARED FITTING. THIS ALLOWED HYDR FLUID IN THE MAIN SYS RESERVOIR TO BE PUMPED OVERBOARD. THE EMERG HYDR SYS HAD A 3 PSN SLCTR: NORMAL, FLAPS DOWN, GEAR DOWN. TESTS OF THE GEAR EXTN SYS REVEALED IT WORKED PROPERLY PER INSTRNS FM THE EMERG CHECKLIST, BUT WITH THE SLCTR IN THE NORMAL PSN, THE LINE FAILURE ALLOWED FLUID TO BE PUMPED FM THE EMERG RESERVOIR TO THE MAIN SYS. A METALLURGICAL EXAM REVEALED THE HYDR LINE HAD FAILED FM MULTIPLE FATIGUE ORIGINS ON THE OUTSIDE DIAMETER OF THE TUBE & ON DIAMETRICALLY OPPOSITE SIDES. LATER, BRITISH AEROSPACE ISSUED A SVC BULLETIN (23-JM-8170) TO REINFORCE THE HYDR LINE.

## Aircraft

- Registration: [N339TE](https://openairdocs.org/deregistered/N339TE-2019-01-17), registration cancelled 2019-01-17, S/N 935, built 1991 (OpenAirDocs)
- Reported make and model: BRITISH AEROSPACE 3201
- Registry model: [British Aerospace BAE JETSTREAM 3201](https://openairdocs.org/model/british-aerospace-bae-jetstream-3201) (registry code 1500217) (OpenAirDocs)
- Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01514, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 935
- Engines: GARRETT TPE 331-12UA 1200 horsepower turbo prop
- Damage: Substantial damage
- Flight: Part 135
- Operator: Trans States Airlines, doing business as Trans World Express
- Registered owner: British Aerospace, Inc.
- Departed: FSM, FT SMITH, AR
- Flight plan: IFR
- Airport: STL, Lambert-St Louis Intl, runway 3L, 11,918 × 200 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 28; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: valid medical--no waivers/lim.; flight hours: 4,200 total, 750 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: -0 °F, dew point -0 °F
- Observed at: STL, 1 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 19910812033899A](https://openairdocs.org/incident/19910812033899A), Aug 12, 1991: Bag JETSTM3201, St Louis, MO, Substantial damage. Hydraulic pressure supply pipe failed due vibration fatigue. Crew unable extend left main gear. Checklist oversight

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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