Pilot Debrief

PAHNKE VERNON A VANS RV 9A near Newark, IL — 2016-09-22

Final reportCEN16LA387
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Date
2016-09-22
Location
Newark, IL, USA
Airport
0C8
Aircraft
PAHNKE VERNON A VANS RV 9A
Registration
N699RV
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Approach

Probable cause

The pilot's failure to properly assemble the fuel pump, which resulted in the loss of fuel pressure and the subsequent partial loss of engine power.

NTSB narrative

The pilot was conducting a cross-country flight in an experimental airplane when he observed the fuel pressure fluctuating, and the engine began to surge. The pilot turned on the backup fuel pump but the engine continued to surge, so he diverted to a nearby airport. The pilot stated that he had difficulty visually acquiring the airport and was losing altitude while circling over the airport. He performed an "S" turn but was still too high. He was running out of runway below him, so he performed a "hard slip" to lose altitude. The airplane stalled 10-15 ft above the runway, hit the ground, and slid about 30 ft before stopping. The primary fuel pump had failed 4 days before the accident. The pilot replaced the fuel pump with a new unit that required partial assembly. He noted during assembly that there was not an O-ring where the lower fitting attached but that the mating surfaces were different between the two pumps and he had believed one was not required. The instructions with the new pump did not address the installation of an O-ring at the fitting. After the accident, the pilot reexamined the box the new fuel pump came in and found an O-ring for the lower fitting. Without the O-ring installed, the fuel system was not able to maintain the fuel pressure necessary to ensure smooth engine operation and resulted in the partial loss of engine power. The pilot stated the accident resulted from this maintenance issue.

Analysis

Primary failure mode
Fuel management
First missed decision gate
Pilot could have ensured proper installation of the fuel pump with an O-ring.

NTSB coding

Evidence available

  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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