DCA85AA015
NTSB Identification: DCA85AA015 .
The docket is stored on NTSB microfiche number 27874.
Scheduled 14 CFR operation of CHINA AIRLINES (D.B.A. SUNG SHAN AIRPORT )
Accident occurred Tuesday, February 19, 1985 in SAN FRANCISCO, CA
Aircraft: BOEING 747 SP-09, registration: N4522V
Injuries: 2 Serious, 271 Uninjured.

WHILE ABV A CLOUD LAYER (TOP AT FL 370) NR THE JET STREAM, AUTOPLT WAS ENGAGED & WAS IN THE PERFORMANCE MNGMNT SYS (PMS)MODE. THE PMS PROVIDED PITCH GUIDANCE TO HOLD FL 410, ROLL GUIDANCE TO AILERONS & SPOILERS FOR ROLL CTL & AUTOTHROTTLE TO MAINT .85 MACH (254 KIAS). ACFT ENCOUNTERED CLR AIR TURBC & AIRSPEED BGN TO VARY BTN .84 & .88 MACH. PMS BGN MOVING THROTTLES FORE & AFT TO HOLD .85 MACH. DRG AUTOTHROTTLE ADJUSTMENTS, #4 ENG THRUST DECREASED & 'HUNG' AT APRX 1.0 EPR & AIRSPEED BGN DECREASING. FLT ENGINEER ATMTD TO MANUALLY RCVR THE #4 ENG THRUST, BUT DID NOT CLOSE THE BLEED AIR VLV BFR ADJUSTING THE #4 THROTTLE. THE #4 ENG REMAINED AT APRX 1.0 EPR. AS THE ACFT SLOWED, AUTOPLT TRIMMED TO HOLD ALT & HDG TIL THE PLT DISENGAGED IT. AT THAT TIME, ACFT ROLLED/YAWED RGT & ENTERED AN UNCTLD DSCNT INTO THE CLOUDS. AS IT BROKE OUT OF THE CLOUDS AT 11,000', CREW RCVRD & LVLD AT 9500'. DRG DSCNT/RCVRY, ACFT WAS DMGD BY ACCELLERATION FORCES & HI SPEED. THERE WAS EVIDENCE THE PLT WAS PREOCCUPIED WITH ENG PRBLM, DIDN'T MONITOR INSTRUMENTS & OVER-RELIED ON AUTOPLT.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

FLIGHT/NAVIGATION INSTRUMENT(S)..INATTENTIVE..PILOT IN COMMAND
DIVERTED ATTENTION..PILOT IN COMMAND
AIRSPEED..NOT MAINTAINED..PILOT IN COMMAND
FLIGHT CONTROLS..IMPROPER USE OF..PILOT IN COMMAND
AIRCRAFT HANDLING..NOT MAINTAINED..PILOT IN COMMAND
DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED..PILOT IN COMMAND


Contributing Factors

WEATHER CONDITION..UNFAVORABLE WIND
WEATHER CONDITION..WINDSHEAR
WEATHER CONDITION..TURBULENCE,CLEAR AIR
OVERCONFIDENCE IN AIRCRAFT'S ABILITY..PILOT IN COMMAND

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