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Accidents · NTSB ERA11LA150 · Final report

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).

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 November 2, 2026. Docket and reports at the NTSB.

What the record shows

Date
February 17, 2011 · about 8:30 pm local time · cases in 2011
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

  1. Sys/Comp malf/fail (non-power) during enroute (cruise) defining event
  2. Loss of engine power (total) during enroute (cruise)
  3. Off-field or emergency landing during emergency descent
  4. 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 other cases naming the fuel system

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

FatalSeriousMinorNone
Flight crew1

Documents from the investigation the NTSB's docket: the evidence folder behind the report

14 documents, released by the NTSB on December 22, 2011. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.

The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.

Connections how this case links to the rest of the register

Aircraft
Place

The whole map of how records connect · these connections as data: /graph/accident/ERA11LA150.json.

The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.

Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.