NTSB Identification: DCA84AA024.
The docket is stored on NTSB microfiche number 25764.
Nonscheduled 14 CFR ZANTOP INT'L AIRLINES, INC.
Accident occurred Wednesday, May 30, 1984 in CHALKHILL, PA
Aircraft: LOCKHEED L-188, registration: N5523
Injuries: 4 Fatal.

AFTER DEPARTING THE BALTIMORE-WASHINGTON ARPT, THE ACFT HAD CLIMBED TO FL 220. ACCORDING TO INFO ON THE COCKPIT VOICE RECORDER (VCR), THE CREW EXPERIENCED GYRO PROBLEMS DURING THE CLIMB. THEY SELECTED THE #1 VERTICAL GYRO TO DRIVE BOTH APPROACH HORIZONS (ATTITUDE INDICATORS), SINCE THERE WAS AN INDICATION OF A MALFUNCTION IN THE #2 VERTICAL GYRO SYS. ABOUT 7 MIN AFTER LEVELING AT FL 220, THE FLT WAS CLEARED TO THE DRYER VOR. SHORTLY AFTER THAT, THERE WERE INDICATIONS OF CONFUSION IN THE COCKPIT WHICH INCLUDED THE STATEMENTS, 'WHAT'S HAPPENING HERE,' 'YOU GOT IT?' & 'NO.' THE ACFT ENTERED A RIGHT DESCENDING SPIRAL; THE INDICATED AIRSPEED INCREASED FROM APRX 205 TO 317 KTS; THEN AN IN-FLT BREAKUP OCCURRED. THE WRECKAGE WAS FOUND SCATTERED OVER AN AREA APRX 2 MI LONG BY 1 MI WIDE. AN EXAM OF THE WRECKAGE REVEALED THAT THE IN-FLT STRUCTURAL FAILURE HAD OCCURRED DUE TO OVERLOAD, THEN A FIRE IGNITED IN THE RIGHT WING AFTER IT HAD FAILED. THE ACFT WAS NOT EQUIPPED WITH AN INDEPENDENT STANDBY ATTITUDE INDICATOR.

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

FLIGHT/NAV INSTRUMENTS,ATTITUDE GYRO..UNDETERMINED

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

DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED..PILOT IN COMMAND

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

AIRCRAFT HANDLING..NOT MAINTAINED..PILOT IN COMMAND

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

SPATIAL DISORIENTATION..PILOT IN COMMAND



Contributing Factors

LIGHT CONDITION..DARK NIGHT

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