NTSB Identification: LAX93FA097.
The docket is stored on NTSB microfiche number 52260.
Accident occurred Wednesday, January 20, 1993 in TULARE, CA
Probable Cause Approval Date: 05/04/1994
Aircraft: BEECH A35, registration: N595B
Injuries: 2 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 CFI IN THE RIGHT SEAT WAS GIVING DUAL TO THE LEFT SEAT CFI, WHO HAD NO EXPERIENCE IN TYPE. DURING THE INITIAL CLIMB, AT ABOUT 400-500 FT AGL, WITNESSES HEARD THE ENGINE LOSE POWER OR SURGE. THE AIRPLANE WAS SEEN TO ROLL TO ONE SIDE AND DESCEND STEEPLY TO IMPACT. THE AIRPLANE HAD BEEN EXTENSIVELY MODIFIED WITH AN UNAPPROVED WING TIP FUEL TANK SYSTEM ADDITION. THE FUEL SELECTOR VALVE FOR THE TIP TANKS DID NOT HAVE ANY PLACARDS SHOWING POSITION OR OPERATION. BOTH CFI'S HAD BEEN GIVEN INCORRECT INSTRUCTIONS ON HOW TO POSITION THE FUEL SYSTEM SELECTOR VALVES BY THE OWNER AND A MECHANIC WHO SIGNED OFF THE ANNUAL INSPECTION. POST-CRASH EXAMINATION REVEALED THAT THE STANDARD FACTORY FUEL SELECTOR WAS IN THE AUX POSITION, AND THE TIP TANKS FUEL SELECTOR VALVE WAS IN A HALF-ON/HALF-OFF POSITION. THE AIRPLANE ALSO HAD A POWERPLANT MODIFICATION FOR INCREASED HORSEPOWER AND OTHER AIRFRAME MODIFICATIONS, NOT ALL OF WHICH WERE DOCUMENTED OR APPROVED. THIS WAS THE FIRST FLIGHT SINCE THE ANNUAL INSPECTION.

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

THE INSTALLATION OF AN UNAPPROVED WING TIP FUEL TANK SYSTEM; AN INADEQUATE ANNUAL INSPECTION WHICH DID NOT NOTE, OR CORRECT, THE UNAPPROVED FUEL SYSTEM ADDITION; A WING TANK FUEL SELECTOR VALVE INSTALLATION WITHOUT ADEQUATE PLACARDS TO SHOW POSITION OR OPERATION; AND INCORRECT INSTRUCTIONS TO THE PILOTS BY THE OWNER AND MECHANIC ON POSITIONING FUEL SELECTOR VALVES WHICH LED TO INADVERTENT MISPOSITIONING BY THE PILOTS AND SUBSEQUENT FUEL STARVATION. IN ADDITION, THE PILOT AT THE CONTROLS FAILED TO MAINTAIN ADEQUATE AIRSPEED FOLLOWING THE POWER LOSS WHICH RESULTED IN AN INADVERTENT STALL/SPIN. A FACTOR WHICH CONTRIBUTED TO THE LOSS OF CONTROL WAS THE DARK NIGHT LIGHT CONDITION.

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