NTSB CAROL · Event
Event SEA05LA176
Aircraft involved
Probable cause & findings
The loss of engine power for undetermined reasons, which resulted in a forced landing and nose over. A factor contributing to the accident was the ground bordering the runway pavement.
Factual narrative
On August 20, 2005, approximately 0750 mountain daylight time, a single-engine Alon A-2A airplane, N5467F, sustained substantial damage following a forced landing after experiencing a loss of engine power near Helena, Montana. The airplane was registered to and operated by a private individual. The certificated private pilot and his sole passenger sustained minor injuries. Visual meteorological conditions prevailed for the local flight, which was operated in accordance with 14 CFR Part 91, and a flight plan was not filed. The flight was originating at the time of the accident. In a written statement the pilot reported that he spent 5 to 10 minutes in the run up area prior to departing; carburetor heat and magneto checks were normal. The pilot stated that after taking off the engine was performing normal, but after reaching an altitude of approximately 100 to 150 feet above ground level (agl) he noticed that the engine was running rough and rpm dropping. The pilot applied carburetor heat, which resulted in a further loss of rpm, prompting him to return the carburetor heat control to OFF. The pilot reported that after informing the control tower operator of the rough running engine, he was cleared for a 180-degree turn to the left for a landing on Runway 9. The pilot reported that his decision to land on Runway 9 was prompted by the reduced engine power available, the lack of runway remaining, and the obstacles at the end of the runway; a fence and a road. The pilot stated that he applied carburetor heat, but due to the additional loss of power, he returned the control to its normal position. The pilot reported that the airplane touched down on the pavement near the departure end of runway 27, bounced once and again contacted the [pavement]. The pilot stated that the airplane then rolled about 10 to 15 feet before leaving the asphalt. The nose gear subsequently collapsed, resulting in the airplane nosing over and coming to rest inverted. The pilot reported no anomalies with the airplane or engine prior to the flight. The temperature and dew point recorded at the airport about the time of the accident were 52 and 31 degrees respectively. A review of a carburetor icing probability chart placed the reported temperature and dew point in the "serious icing - descent power" area of the chart. A Federal Aviation Administration (FAA) airworthiness inspector, who examined the airplane, reported that both magnetos exhibited proper timing, all spark plugs appeared normal, with the exception of the #4 spark plug, which was fouled. Flight control continuity was found at all control surfaces. Damage to the airplane included both propeller blades bent aft, the nose gear collapsed aft, damage to the firewall, the left wing root area and aft spar damaged, and the horizontal stabilizer being bent downward. After taking off on Runway 27 (9,000 feet X 150 feet) and climbing to an altitude of between 100 and 150 feet above ground level, the engine began to run rough. The pilot applied carburetor heat, which resulted in a further loss of engine rpm, prompting the pilot to make a left turn for a landing on Runway 9. The airplane touched down on the pavement near the departure end of Runway 27, bounced once and contacted the pavement a second time. The airplane then rolled about 10 to 15 feet before exiting the runway surface and impacting a grassy dirt surface, which resulted in the nose gear collapsing and the airplane nosing over, coming to rest in an inverted position. Examination of the airframe and engine revealed no anomalies that would have prevented normal operation. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_2005_SEA05LA176.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- NASA NTRS 2026 · Contractor Report (CR)
Icing Physics Studies Using the 3D SIDRM Test Article: 2023 Icing Tests Analysis
In-flight icing is an important safety issue and is a factor that affects aircraft design and performance. Newer regulations are driving a need for improvements in airframe and engine icing simulation…
- arXiv 2025 · arXiv preprint
Multi-Agent Deep Reinforcement Learning for UAV-Assisted 5G Network Slicing: A Comparative Study of MAPPO, MADDPG, and MADQN
The growing demand for robust, scalable wireless networks in the 5G-and-beyond era has led to the deployment of Unmanned Aerial Vehicles (UAVs) as mobile base stations to enhance coverage in dense urb…
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Mathematical Model on the Temporal Dynamics of Aviation Competitive Pricing
This study investigates the competitive dynamics of airport pricing using U.S. airport data to validate the findings. It employs linear and nonlinear ordinary differential equation models to analyze t…
- NASA NTRS 2025 · Presentation
NASA Icing Update – March 2025
This NASA Icing Update was prepared for presentation to the SAE International AC-9C Inflight Icing Technology Committee. This update includes the following topics: planned Rotational Icing Scaling tes…
- arXiv 2024 · arXiv preprint
An energy-stable phase-field model for droplet icing simulations
A phase-field model for three-phase flows is established by combining the Navier-Stokes (NS) and the energy equations, with the Allen-Cahn (AC) and Cahn-Hilliard (CH) equations and is demonstrated ana…
- NASA NTRS 2024 · Presentation
NASA Icing Update – Oct 2024
This presentation provides a status update on select NASA icing research activities for the SAE AC-9C Icing Technical Committee Meeting on Oct 21, 2024.
Browse the full corpus — academia portal ↗