BEECH 95-B55 (T4 near Whites Creek, TN — 2008-11-24
- Date
- 2008-11-24
- Location
- Whites Creek, TN, USA
- Aircraft
- BEECH 95-B55 (T4
- Registration
- N412ES
- Category
- Airplane
- Highest injury
- Fatal
- Fatalities
- 3
- Phase of flight
- Approach
Probable cause
The pilot's failure to feather the left propeller and secure the left engine following the total loss of left engine power, and his subsequent failure to maintain airspeed, lateral, and directional control of the airplane. Contributing to the accident was the failure of maintenance personnel to properly tighten the fuel supply hose at the engine-driven fuel pump.
Contributing factors
Contributing to the accident was the failure of maintenance personnel to properly tighten the fuel supply hose at the engine-driven fuel pump.
NTSB narrative
During flight in instrument meteorological conditions, the left engine experienced a total loss of power due to the separation of the flexible fuel supply hose between the left engine firewall fitting and the engine-driven fuel pump inlet fitting due to an inadequately torqued B-nut. The pilot informed air traffic control of a discrepancy, although he was not specific in the nature of the problem. A momentary change in heading to the left occurred consistent with the pilot’s failure to maintain directional control of the airplane following the loss of left engine power. Radar data indicated that the airplane was allowed to decelerate, followed by a loss of lateral and directional control and a subsequent flat spin to the left. The stall warning horn was recorded during the pilot's comment to the controller that he was in a spin. The airplane descended uncontrolled and crashed into a wooded area behind a home and was destroyed by impact and a postcrash fire. No preimpact mechanical failure or malfunction of the airplane or of either engine was noted. Acoustic analysis of engine rpm signatures reflect a steadily decreasing rpm to 1,760, most likely from the left engine, which is below the normal operating range. The analysis indicated an rpm signature of 2,140, most likely from the right engine, which was in the normal operating range. The pilot neither feathered the left propeller nor secured the left engine following the total loss of power per the Pilot's Operating Handbook and Aircraft Flight Manual, and there were no mechanical discrepancies with the propeller or propeller governor that would have prevented him from doing so. Operational testing of the left engine with an exemplar flexible fuel hose that was finger-tight resulted in the separation of the line from the inlet fitting. The test runs determined that when finger-tight the B-nut loosened and tightened varying amounts with different power applications. Rebuilt engines were installed 9 months earlier and there was no entry indicating that the flexible fuel hoses were replaced at that time. There was no record that the left flexible fuel hose was ever replaced since the airplane was manufactured in 1978. Although the airplane manufacturer recommends that flexible fuel hoses be replaced when conditions warrant, at engine overhaul, or 5 years, whichever occurs first, there is no evidence to suggest that the age of the hose contributed to its separation from the engine-driven fuel pump inlet fitting.
Analysis
- Primary failure mode
- Loss of control
- First missed decision gate
- Pilot could have requested assistance earlier to avoid loss of control.
NTSB coding
Evidence available
- ATC audio
- ADS-B / radar
- Photos
- 47 docket documents
Docket documents47
- Specialist's Sound Spectrum Study - Air Traffic Control Recordingatc
- Release of Aircraft Wreckage, NTSB Form 6120.15form
- Personnel Statementsinterview
- Statement Concerning Pilot Statusinterview
- Statement of Party Representatives to NTSB Investigationinterview
- Witness Statementsinterview
- Autopilot Flight Manual Supplementother
- Autopilot Installation Recordsother
- Daily Record of Facility Operationother
- Engine Flight Manual Supplementother
- Excerpts from Airframe Logbooksother
- Excerpts from Pilot's Operating Handbook and FAA Approved Airplane Flight Manualother
- Flight Progress Stripother
- Fuel Recordsother
- Google Earth Plot Depicting Witness and Accident Site Locationother
- Hose Specification Sheetother
- IMG 17 - Digital Camera Studyother
- Left Engine Logbookother
- Letters from Teledyne Continental Motors Concerning Fuel Line and Fuel Pumpother
- Record of NTSB Conversationsother
- Right Engine Logbookother
- Supplemental Type Certificate (STC) SA432SOother
- Time Limitsother
- Photo 10: NTSB Digital Photograph. Close-Up View of the Inlet Fitting End of the Fuel Hose That was Found Separated at the Left Engine-Driven Fuel Pump.photos
- Photo 11: NTSB Digital Photograph. Close-Up View of the Inlet Fitting End of the Fuel Hose That was Found Separated at the Left Engine-Driven Fuel P{ump.photos
- Photo 12: NTSB Digital Photograph. View of the Left Engine-Driven Fuel Pump, Drive Coupling, and Fuel Supply Hose.photos
- Photo 13: NTSB Digital Photograph. View of the Left Propeller Spinner. Note the Upward Crushing.photos
- Photo 14: NTSB Digital Photograph. View of the Right Propeller Spinner. Note the Upward Crushing.photos
- Photo 1: NTSB Digital Photograph. View of the Wreckage at the Accident Site.photos
- Photo 2: NTSB Digital Photograph. View of the Wreckage at the Accident Site. Note the Tall Trees Located Around the Wreckage.photos
- Photo 3: NTSB Digital Photograph. View Showing the Trees Behind and Ahead of the Left Wing.photos
- Photo 4: NTSB Digital Photograph. View of the Left Engine and Propeller.photos
- Photo 5: NTSB Digital Photograph. View of the Right Engine and Propeller.photos
- Photo 6: NTSB Digital Photograph. View Showing Broken Tree Limbs on One Tree.photos
- Photo 7: NTSB Digital Photograph. View of the Bottom of the Left Wing.photos
- Photo 8: NTSB Digital Photograph. View of the Separated Fuel Supply Hose at the Left Engine-Driven Fuel Pump Inlet Fitting.photos
- Photo 9: NTSB Digital Photograph. Close-Up View of the Left Engine-Driven Fuel Pump Inlet Fitting.photos
- Radar Dataradar
- Radar Plotsradar
- Materials Laboratory 15 - Factual Reportreport
- Reports from Local Agencies-Metropolitan Police Department Nashville, Tennesseereport
- Reports from Parties to the Investigation-Hartzell Propeller, Inc.report
- Reports from Parties to the Investigation-Teledyne Continental Motorsreport
- Toxicological Reportsreport
- Weather Reports and Recordsreport
- Transcript of Radio Communicationstranscript
- Transcription of Weather Briefingtranscript
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