# NTSB ERA21LA075: Kolb Firestar, N7094T, Durham, NC, December 11, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: December 11, 2020, 13:00 local (18:00 UTC) - Place: Durham, NC · Lake - Coordinates: 36.024094, -78.716475 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.0241&lon=-78.7165&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Fuel starvation](https://openairdocs.org/ntsb-events/191) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA FSDO - NTSB case key (mKey): 102419 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA075 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102419/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102419 - Page: https://openairdocs.org/ntsb/ERA21LA075 ## Probable cause A total loss of engine power due to fuel starvation as the result of a degraded fuel primer check valve. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Fuel system: fuel transfer valve](https://openairdocs.org/ntsb-findings/01022824): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Kolb FIRESTAR II, 1 case](https://openairdocs.org/ntsb-findings/01022824/cases.md?model=059010O), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/01022824/cases.md) - [Fuel system: fuel transfer valve](https://openairdocs.org/ntsb-findings/01022824): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Kolb FIRESTAR II, 1 case](https://openairdocs.org/ntsb-findings/01022824/cases.md?model=059010O), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/01022824/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Fuel starvation](https://openairdocs.org/ntsb-events/191) (defining event); cases with it: [Kolb FIRESTAR II, 1 case](https://openairdocs.org/ntsb-events/191/sequence.md?model=059010O), [All aircraft, 733 cases](https://openairdocs.org/ntsb-events/191/sequence.md) - [Enroute: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Kolb FIRESTAR II, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=059010O), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## 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](https://openairdocs.org/aircraft/N7094T), registered now, S/N 522, built 1994 (OpenAirDocs) - Reported make and model: KOLB FIRESTAR (II) - Registry model: [Kolb FIRESTAR II](https://openairdocs.org/model/kolb-firestar-ii) (registry code 059010O) (OpenAirDocs) - Registry engine: [Rotax 503 DCDI](https://openairdocs.org/engine/rotax-503-dcdi) (registry code 55566, 2 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 522 - Year built: 1994 - Airframe hours: 438 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: minor; 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 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20201211017619A](https://openairdocs.org/incident/20201211017619A), Dec 11, 2020: Kolb FIRESTAR II, Durham, NC, Destroyed. At approximately 1850Z N7094T was over falls lake at about 500 ft AGL when the engine began to loose power and the aircraft was unable to maintain altitude.… ## Docket (6 files) The files NTSB released with the investigation on September 30, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102419. 3.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11836197&FileExtension=pdf&FileName=Pilots%206120%20Report_Redacted-Rel.pdf - Pilot's original statement to FAA (item 2, PDF, 2 pages, 125 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11888018&FileExtension=pdf&FileName=Pilot%27s%20Original%20Statement_Redacted-Rel.pdf - FAA inspectors statement (item 3, PDF, 1 page, 78 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11888451&FileExtension=pdf&FileName=Inspector%20Statement%20%20N7094T-Rel.pdf - Maintenance record excerpt (item 4, PDF, 1 page, 85 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11889073&FileExtension=pdf&FileName=Log%20book%20Maintenance%20entry%20June%202020_Redacted-Rel.pdf - Memorandum for record_email summary of examination findings (item 5, PDF, 2 pages, 372 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11889481&FileExtension=pdf&FileName=Memorandum%20for%20Record-Email%20Summary%20of%20Examination%20Findings-Rel.pdf - Photo array_ accident and damage photographs (item 6, PDF, 4 pages, 768 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11888646&FileExtension=pdf&FileName=Accident%20Site%20and%20Damage%20Photographs-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.