NTSB Identification: ATL94FA056.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Tuesday, March 01, 1994 in BAY MINETTE, AL
Probable Cause Approval Date: 04/07/1995
Aircraft: CESSNA P210R, registration: N55MM
Injuries: 4 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

THE PILOT RECEIVED A FULL WEATHER BRIEFING BEFORE THE IFR FLIGHT. CONVECTIVE THUNDERSTORM ACTIVITY WAS FORECAST FOR THE ROUTE OF FLIGHT, THERE WERE NUMEROUS THUNDERSTORMS IN THE AREA AT THE TIME OF DEPARTURE, AND A TORNADO WATCH WAS IN EFFECT AT THE TIME OF THE ACCIDENT. AFTER LEVELING AT FL210, HE REPORTED THAT CONDITIONS WERE 'GETTING ROUGH.' SHORTLY THEREAFTER, HE REPORTED PROBLEMS WITH THE AIRCRAFT GYRO SYSTEM, THEN SAID ALL GYRO'S WERE 'OUT.' HE ELECTED TO DESCEND IN AN ATTEMPT TO LOCATE VFR WEATHER. AS THE AIRCRAFT DESCENDED, RADIO & RADAR CONTACT WERE LOST. WRECKAGE WAS FOUND DISTRIBUTED OVER AN AREA ABOUT 4-1/2 MILES IN LENGTH. AN EXAM OF THE WRECKAGE REVEALED EVIDENCE THAT THE WINGS HAD FAILED IN AN UPWARD DIRECTION. DURING AN EXAM OF THE VACUUM POWERED ATTITUDE GYRO, NO ROTATIONAL SCRATCHING WAS FOUND ON THE GYRO OR IN THE GYRO HOUSING. AN EXAM OF THE LEFT VACUUM PUMP REVEALED THAT THE PLASTIC DRIVE COUPLING HAD SIGNS OF HEAT STRESS & MELTING, THAT THE INTERNAL VEINS WERE BROKEN & CRACKED & THAT THERE WAS A DEPOSIT OF CARBON MATERIAL INSIDE THE HOUSING. THE RIGHT VACUUM PUMP HAD EVIDENCE OF ROTATIONAL SCRATCHING. THE GYROS SHOULD HAVE OPERATED WITH 1 VACUUM PUMP IN OPERATION.

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

THE PILOT'S FAILURE TO MAINTAIN CONTROL OF THE AIRCRAFT DUE TO SPATIAL DISORIENTATION, AND EXCEEDING THE DESIGN STRESS LIMITS OF THE AIRCRAFT. FACTORS RELATED TO THE ACCIDENT WERE: THE PILOT'S FLIGHT INTO KNOWN ADVERSE WEATHER CONDITIONS, OVERCONFIDENCE IN HIMSELF AND THE AIRPLANE, FAILURE OF THE LEFT VACUUM PUMP, PARTIAL LOSS OF THE VACUUM SYSTEM, AND AN INOPERATIVE ATTITUDE INDICATOR.

Full narrative available

Index for Mar1994 | Index of months