ERA21LA075

NTSB accident investigation · Kolb Firestar · Durham, NC · December 11, 2020

Accident · No injuriesClass 3 · LimitedFinal report
Date
December 11, 2020, 13:00 local (18:00 UTC)
Place
Durham, NC · Lake
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N7094TKolb Firestar
Defining event
Enroute: Fuel starvation
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Eastern Region Aviation
Parties
FAA FSDO
FAA report
20201211017619A
Case key
102419

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

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

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Fuel system: fuel transfer valveAircraft › Aircraft systems · Damaged/degradedKolb FIRESTAR II: 1 caseAll aircraft: 7 casesProbable cause
Fuel system: fuel transfer valveAircraft › Aircraft systems · MalfunctionKolb FIRESTAR II: 1 caseAll aircraft: 7 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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 narrative

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.

Aircraft

Registration
N7094T
Reported as
Kolb Firestar (II)
Category
Airplane
Serial number
522
Built
1994
Airframe hours
438
Engine
Rotax 503DCDI, 50 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental light sport (Special)
Last inspection
Condition · June 15, 2020
Departed
8NC8 · Durham, NC
Airport
8NC8 · Lake Ridge Aero Park Airport
Equipment
None

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
63
Injuries
Minor
Certificate
Sport Pilot
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
BasicMed
Last flight review
July 7, 2020
Seat
Front
Restraint
4-point
Flight hours
2,420 total · 44.2 in this make and model · 2,400 as pilot in command · 23 in the last 90 days · 8.8 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Variable at 3 knots
Visibility
10 statute miles
Temperature
64 °F, dew point 48 °F
Altimeter
30.18 inHg
Observed at
RDU, 3 nm away

Docket · 6

The files NTSB released with the investigation on September 30, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.6 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.