Amateur-built KOLB AIRCRAFT MK III accident near Stetson, Maine, February 17, 2011
On February 17, 2011 at about 8:30 pm local time, a amateur-built KOLB AIRCRAFT MK III, registered N213, was substantially damaged in an accident during enroute (cruise) near Stetson, Maine. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The in-flight failure of the No. 1 composite propeller blade due to fatigue, which resulted in a violent vibration, loss of engine power, and a subsequent forced landing to unsuitable terrain.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 17, 2011 · about 8:30 pm local time
- Place
- Stetson, Maine · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built KOLB AIRCRAFT MK III
- Registration
- N213 · registry record · serial M3-248
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was in cruise flight at 1,500 feet over a heavily wooded area when the airplane began to vibrate violently before sustaining a total loss of engine power. The pilot made a forced landing and the airplane collided with trees and the ground. The pilot stated that, about 30 flight hours before this accident, the airplane experienced a similar severe vibration in flight. He shut down the engine and made a successful forced landing to a nearby airport. Examination of the airplane revealed that a triangle-shaped aluminum plate on the rear of the propeller hub had cracked. The pilot installed a new propeller hub and the original propeller blades about 7 months before the accident and began flying again without any vibrations. The total hours on the propeller blades are unknown. A postaccident examination at the accident site revealed that both carburetors had separated from the engine assembly and were hanging by their fuel lines and throttle cables. One composite propeller blade was delaminated with a large section missing. The remaining two propeller blades appeared to be intact without comparable or crash-related damage. The carburetor detachment likely caused the final engine failure and this separation was likely a consequence of the severe vibration. Metallurgical examination of the propeller blades identified that separation of a portion of blade No. 1 initiated as a transverse fracture, originating near the trailing edge of the blade. The transverse fracture was progressive in nature, with the crack propagating in some combination of fatigue and/or stress rupture under continually applied loads. Blade No. 2 also exhibited a pattern of parallel transverse cracks on its aft side. Blade No. 3 was also visibly damaged, with significant delamination or disbonding of the woven carbon-fiber composite skin from the forward side of the blade, along with delamination at the trailing edge. Blade No. 3 also exhibited a pattern of parallel transverse cracks on its aft side. This damage was consistent with bending of the tip of the blade forward under air loading.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Sys/Comp malf/fail (non-power) during enroute (cruise) defining event
- Loss of engine power (total) during enroute (cruise)
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller blade section › Fatigue/wear/corrosion
- Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Contributed to outcome
- Aircraft › Aircraft systems › Fuel system › Fuel distribution › Damaged/degraded
Pilot
- Certificate: sport pilot
- Ratings: single-engine land
- Flight time: 3,000 hours in all; 200 in this make and model; 4 in the last 90 days; 3 in the last 30 days; 3,000 as pilot in command
- Last flight review: October 21, 2009
- Medical certificate: None
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 177 hours
- Last inspection: condition inspection, March 20, 2010; 59 hours since
- Maximum gross weight: 1,050 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 582 (piston); 0 hours total
The flight
- Departed from: OLD Old Town ME at 6:30 pm
- Destination: 1BO Dexter ME
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 310° at 3 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 2,500 ft; a few clouds at 1,500 ft
- Temperature: 43°F (6°C), dew point 36°F (2°C)
- Altimeter: 30.00 inHg
- Observation at 8:53 pm from BGR, 11 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ERA11LA150.