Aviation Accident Summaries

Aviation Accident Summary ERA21LA075

Durham, NC, USA

Aircraft #1

N7094T

KOLB FIRESTAR

Analysis

The pilot reported that about 20 minutes into the flight, at an altitude about 500 ft above ground level, the engine started losing power. The pilot noted no anomalies on the engine monitoring system, but his attempts to increase engine power were unsuccessful, and he chose to conduct a forced landing in a lake. During the landing flare, the wheels contacted the water surface and the airplane nosed over and came to rest inverted and submerged. Examination of the airplane following recovery from the lake revealed that the fuel primer bulb was missing a spring on the fuel inlet check valve, which prevented the check ball from seating properly. This likely blocked the incoming fuel and thereby resulted in fuel starvation and the total loss of engine power.

Factual Information

On December 11, 2020, about 1300 eastern daylight time, a Kolb Firestar II, N7094T, was substantially damaged when it was involved in an accident near Durham, North Carolina. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, about 20 minutes into the flight, the engine started losing power. The airplane was about 500 ft above ground level; the engine monitoring system did not indicate an engine problem. The pilot’s attempts to increase engine power were unsuccessful, and the airplane continued to lose altitude. The pilot decided to conduct a forced landing on a lake. During the landing flare, the wheels contacted the water surface and the airplane immediately flipped forward and came to rest upside down and partially submerged. The pilot egressed and swam to the surface, where he was rescued by an individual on a personal watercraft. The airplane sustained substantial damage to the wings and fuselage. The tail separated about 2 ft aft of the fuel tank and the leading outboard edges of the wings were crushed and torn open. The airplane remained submerged until the following day, when it was recovered and transported to the owner’s hangar for further examination. The owner performed the examination and discovered that the fuel primer bulb was missing the fuel input primer spring. (see figure 1.) Figure 1 - Primer bulb illustration.   The owner’s observation of the check “ball” valve and lack of spring tension kept the ball from seating properly during normal operations. The owner reported that the system should ideally be installed in a vertical position, but on the accident airplane, it was installed horizontally (see figure 2). Without the spring, gravity would not be adequate to keep the check ball from migrating inside the primer inlet fuel line.

Probable Cause and Findings

A total loss of engine power due to fuel starvation as the result of a degraded fuel primer check valve.

 

Source: NTSB Aviation Accident Database

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