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NTSB Report
August 12, 1991 · British Aerospace 3201 · N339TE
St Louis, MO
Overview
Report Status
Probable Cause
Event Type
Accident
Date
August 12, 1991
Injury Outcomes
No injuries (7 uninjured)
Location
St Louis, MO
Aircraft
British Aerospace 3201
Tail Number
N339TE
Operator
Trans States Airlines
Injuries
None
Aircraft Damage
Substantial
NTSB Number
CHI91MA260
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.
NTSB 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.
Full Narrative
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.
Flight
Event TypeAccident
Event Time11:09 CDT
Nearest AirportLambert-St Louis Intl (0nm N)
Runway3L
Runway Length11918 ft
Runway Width200 ft
Flight Plan FiledIFR
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBritish Aerospace 3201
Tail NumberN339TE
Aircraft CategoryAir
DamageSubstantial
OperatorTrans States Airlines
Operating RulePart 135
Engines2
Engine TypeTurboprop
Engine DetailsGarrett · TPE 331-12UA · Turboprop · 1200
Seats21
People & Injuries
Injury SummaryNo injuries (7 uninjured)
Fatal0
Serious0
Minor0
Uninjured7
Total7
Crew 1Age 28 · None
Conditions
ConditionsVMC
LightDaylight
Wind70° @ 6 kt
Visibility10 sm
CeilingBroken clouds 25000 ft
Temperature / Dew Point0 C / 0 C
Altimeter0
Observation Time16:13
Weather SourceWFAC