# NTSB ATL93LA148: Beech V35A, N7733R, Knoxville, TN, August 27, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 27, 1993, 17:15 local (21:15 UTC) - Place: Knoxville, TN - Coordinates: 35.86042, -84.100021 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.8604&lon=-84.1000&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report September 27, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 3256 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL93LA148 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3256/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=3256 - Page: https://openairdocs.org/ntsb/ATL93LA148 ## Probable cause 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. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, takeoff - initial climb - fuel system - blocked(partial) (cause) - acft/equip inadequate,supplemental type cert, manufacturer (cause) - insufficient standards/requirements, faa(organization) (contributing factor) - fluid,fuel - starvation (cause) - Forced landing, descent - emergency - In flight collision with object, descent - emergency - object - tree(s) ## Analysis 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. ## Factual narrative 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. ## Aircraft - Registration: [N7733R](https://openairdocs.org/deregistered/N7733R-2013-05-09), registration cancelled 2013-05-09, S/N D-8874, built 1968 (OpenAirDocs) - Reported make and model: BEECH V35A - Registry model: [Beech V35A](https://openairdocs.org/model/beech-v35a) (registry code 1151544) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: D8874 - Airframe hours: 3600 - Engines: CONTINENTAL IO-520-B 285 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Bell Chemical Co. Inc,. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 20, 1993, 5 hours before - Departed: NONE - Airport: NONE, Sanders Private ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: right; flight hours: 13,000 total, 9,000 in this make and model, 13,000 as pilot in command, 100 in the last 90 days, 20 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 110° at 11 knots - Visibility: 7 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 79 °F, dew point 64 °F - Altimeter: 30.00 inHg - Observed at: TYS, 15 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19930827031409A](https://openairdocs.org/incident/19930827031409A), Aug 27, 1993: Beech V35A, Knoxville, TN, Substantial damage. Lost power on climbout. Landed in trees. Corrosive material in floscan transducer. Blocked fuel. Sat idle for years ## Other investigations on N7733R (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB MIA77FKG66](https://openairdocs.org/ntsb/MIA77FKG66), Aug 17, 1977: Beech B23 (N7733R), Hazelhurst, GA, destroyed ## Docket (7 files) The files NTSB released with the investigation on June 3, 1995, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=3256. 891 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 378 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442578&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Supplement E - Second Pilot Information (item 2, .PDF, 89 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442579&FileExtension=.PDF&FileName=Supplement%20E%20-%20Second%20Pilot%20Information-Redacted.PDF - Operator's Statement (item 3, .PDF, 40 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442580&FileExtension=.PDF&FileName=Operator%27s%20Statement-Redacted.PDF - DOT Supplemental Type Certificate, STC-SA2834WE (item 4, .PDF, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442581&FileExtension=.PDF&FileName=DOT%20Supplemental%20Type%20Certificate,%20STC-SA2834WE-Redacted.PDF - FAA Form 337, Major Repairs and Alterations (item 5, .PDF, 120 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442582&FileExtension=.PDF&FileName=FAA%20Form%20337,%20Major%20Repairs%20and%20Alterations-Redacted.PDF - FAA Service Difficulty Report (SDR) (item 6, .PDF, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40001889&FileExtension=.PDF&FileName=FAA%20Service%20Difficulty%20Report%20(SDR)-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 7, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442583&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.