Pilot Debrief

BEECH H35 near Parker, AZ — 2014-05-22

Final reportWPR14LA199
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Date
2014-05-22
Location
Parker, AZ, USA
Airport
P20
Aircraft
BEECH H35
Registration
N4689D
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The improperly attached fuel line and cracked fuel diaphragm due to unknown personnel’s inadequate maintenance, which resulted in the loss of engine power during cruise flight and the subsequent forced landing onto rough terrain.

NTSB narrative

The flight instructor and pilot-rated owner were operating the airplane in cruise flight when the engine lost power. They manipulated the engine and fuel controls in an attempt to regain engine power, but the engine would not restart. They subsequently conducted a forced landing onto rough terrain. During the landing roll, the nose landing gear folded underneath the airplane, and the right wing sustained substantial damage. The engine was test run, and it would not maintain power unless the electric boost pump was operating. During a postrun examination of the engine, the fuel return line from the engine-driven fuel pump was found loose at the pump connection, and fuel was noted dripping from the rigid fuel line near the pump connection. The line was removed, and the "B" nut ferrule was found cracked. The "B" nut and the fuel pump fitting threads were damaged. The fuel pump and fuel control assembly were found intact, and, during a test run, functioned properly. During testing of the fuel manifold valve, a leak was observed at the vent port, indicating that the diaphragm was compromised. Based on this evidence, it is likely that the improperly attached fuel return line on the fuel pump and the leak from the fuel manifold valve led to a loss of pressure in the engine fuel delivery system, which resulted in the loss of engine power. The investigation could not determine when or by whom the maintenance was performed.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked fuel levels before departure to prevent power loss.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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