# NTSB CEN21LA425: Kolb Mark III, N4365E, Steamboat Springs, CO, September 14, 2021 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: September 13, 2021, 18:30 local (Sep 14, 2021, 00:30 UTC) - Place: Steamboat Springs, CO · open field. - Coordinates: 40.49427, -106.98277 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.4943&lon=-106.9828&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 103901 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA425 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103901/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103901 - Page: https://openairdocs.org/ntsb/CEN21LA425 ## Probable cause The pilot’s failure to maintain adequate airspeed and his exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=05618NB), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05618NB), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=05618NB), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05618NB), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=05618NB), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Byler Dan W KOLB MARK III, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05618NB), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot flew the airplane with the previous owner in Indiana before purchasing it and driving it on a trailer to Steamboat Springs. A witness reported that the pilot intended to taxi around his private airstrip to get a better feel for the airplane. The airplane subsequently lifted off the ground, cleared several fences, and was about 20 ft above the ground when the airplane’s nose suddenly lowered and impacted the ground. The airplane sustained substantial damage to the fuselage. The pilot told the witness that he did not intentionally lower the nose of the airplane. The pilot later told a family member that he stalled the airplane. The airplane was not made available for investigators to examine. ## Factual narrative On September 13, 2021, at 1830 mountain daylight time, a Kolb Mark III airplane, N4365E, was substantially damaged when it was involved in an accident near Steamboat Springs, Colorado. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot’s wife, who witnessed the accident, reported that the pilot recently purchased the airplane. She stated that the pilot flew the airplane with the previous owner in Indiana before driving it on a trailer to Steamboat Springs. On the day of the accident, the pilot intended to taxi the airplane around his private airstrip to get used to the feel of the airplane. The airplane subsequently lifted off, cleared several fences, but only made it about 20 ft above the ground when the airplane’s nose suddenly lowered and impacted the ground. The airplane sustained substantial damage to the fuselage. The witness stated the engine was still running and she was unable to turn it off when she reached the accident site. The pilot told the witness that he did not command the airplane down but that it just fell. The pilot later told a family member that he stalled the airplane. The airplane was not made available for investigators to examine the airframe or flight control system. The pilot did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report (NTSB Form 6120.1). ## Aircraft - Registration: [N4365E](https://openairdocs.org/deregistered/N4365E-2023-04-01), registration cancelled 2023-04-01, S/N M3086, built 1991 (OpenAirDocs) - Reported make and model: KOLB Mark III - Registry model: [Byler Dan W KOLB MARK III](https://openairdocs.org/model/byler-dan-w-kolb-mark-iii) (registry code 05618NB) (OpenAirDocs) - Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: M3086 - Year built: 1991 - Engines: ROTAX 582 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Airport: n/a, Private Strip, runway UNK, grass/turf - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 69; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 41 °F - Altimeter: 30.13 inHg - Observed at: KSBS, 5 nm away - METAR: KSBS 140015Z AUTO 31007KT 10SM CLR 22/05 A3013 RMK AO1 T02160052 ## 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 20210914016529A](https://openairdocs.org/incident/20210914016529A), Sep 14, 2021: Byler Dan W KOLB MARK III, Steamboat Sprin, CO, Substantial damage. On September 14, 2021 at approximately 05:30 am MDT, N4365E, an experimental Kolb Mark III, took of from a private grass strip. Shortly after rotation the… ## Docket (3 files) The files NTSB released with the investigation on September 20, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103901. 436 KB in all. - Witness statement (item 1, PDF, 1 page, 88 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16010280&FileExtension=pdf&FileName=CEN21LA425%20-%20Record%20of%20Conversation-Rel.pdf - Photos (item 2, PDF, 2 pages, 277 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16010270&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Accident report form memo (item 3, PDF, 1 page, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16012470&FileExtension=pdf&FileName=6120%20memo-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.