KNOXVILLE, TN, USA
N7733R
BEECH V35A
DURING CLIMB OUT, THE AIRPLANE EXPERIENCED A REDUCTION IN ENGINE POWER FOLLOWED BY A COMPLETE LOSS OF POWER. THE FLIGHT INSTRUCTOR ASSUMED CONTROL OF THE AIRPLANE AND MADE A FORCED LANDING INTO A WOODED AREA; THE AIRPLANE COLLIDED WITH TREES AND FLIPPED INVERTED. EXAMINATION OF THE AIRCRAFT FUEL SYSTEM REVEALED CORROSIVE MATERIALS IN THE FUEL FLOSCAN TRANSDUCER; CORROSIVE MATERIALS BLOCKED BOTH THE IN AND OUT PORTS. THE TRANSDUCER IS PART OF A SUPPLEMENTAL TYPE CERTIFICATE MODIFICATION THAT MEASURES FUEL FLOW. THE ASSEMBLY IS MOUNTED ON TOP OF THE ENGINE, AND IS THE FINAL COMPONENT IN THE FUEL SYSTEM BEFORE THE FUEL FLOW DIVIDER. ACCORDING TO THE OPERATOR, THE AIRCRAFT HAD NOT BEEN FLOWN IN SEVERAL YEARS. A CURRENT ANNUAL INSPECTION HAD BEEN COMPLETED. HOWEVER, THERE IS NO INSPECTION PROCEDURE FOR THE TRANSDUCER ASSEMBLY.
On August 27, 1993, at 1715 eastern daylight time, a Beech, V35A, N7733R, collided with trees during an attempted takeoff from a private airstrip near Knoxville, Tennessee. The instructional flight operated under 14 CFR Part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage, and the certified flight instructor and commercial rated pilot received minor injuries. The accident occurred during the initial takeoff attempt from the private airstrip. According to the flight instructor, the engine started losing power shortly after liftoff, and the flight instructor elected to continue to climb out until the engine quit. The instructor pilot took the flight controls from the student and attempted a forced landing into a wooded area. The airplane collided with the trees and flipped inverted. A subsequent examination of the aircraft fuel system revealed corrosive materials in the fuel floscan transducer mounted on top of the engine upstream from the injection system distributor valve assembly. The white and brown corrosive materials blocked the in and out ports of the transducer; no other contaminants were discovered in the fuel system. A review of the aircraft maintenance logs disclosed that a Symbolic Displays, Inc., FT-100 Fuel Flow Indicating System, was installed in accordance with Federal Aviation Administration, Supplemental Type Certificate, Number STC SA 3824WE, on June 14, 1985 (see attached STC and FAA Form 337). According to the mechanic who performed the last annual inspection, there is no inspection procedure for the fuel floscan transducer. Additionally, N7733R had not been flown for several years before the recent annual inspection.
INADEQUATE ANNUAL INSPECTION PROCEDURES FOR THE FUEL SYSTEM, WHICH RESULTED IN FUEL STARVATION DUE TO BLOCKAGE OF THE FUEL FLOSCAN TRANSDUCER. A FACTOR WAS INSUFFICIENT FAA INSPECTION STANDARDS/REQUIREMENTS.
Source: NTSB Aviation Accident Database
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