NTSB CAROL · Event
Event SEA04CA122
Aircraft involved
Probable cause & findings
The pilot's failure to maintain aircraft control resulting in an uncontrolled descent and subsequent roll over. Low altitude flight and the pilot's encounter with settling with power were contributing factors.
Factual narrative
On July 5, 2004, at 1500 Pacific daylight time, a Robinson R-22 Mariner, N856HA, registered to and operated by Hillsboro Aviation as a 14 CFR Part 91 instructional flight, experienced a hard landing followed by a rollover at the Portland-Hillsboro Airport, Hillsboro, Oregon. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local instructional flight. The helicopter was substantially damaged and the certified flight instructor was not injured, while the commercial pilot (student) received minor injuries. In a written statement, the flight instructor reported that they were in the process of practicing "maximum performance takeoff abort - backwards." The student was on the controls during the maximum performance takeoff phase to an altitude of about 150 feet above ground level, and the instructor took over the controls to demonstrate the abort procedures. The instructor took the controls just prior to call for the abort. When the abort phase began, the instructor applied aft cyclic and slightly lowered the collective. The helicopter had been in a tail low attitude and started to descend into "settling with power." The instructor applied forward cyclic and lowered the collective, however the helicopter did not have sufficient altitude to level out or gain airspeed to recover before impacting the ground on the right side skid. The helicopter pivoted around about 180 degrees then rolled over onto its left side. The flight instructor reported that they were in the process of practicing "maximum performance takeoff abort - backwards." The student was on the controls during the maximum performance takeoff phase to an altitude of about 150 feet above ground level, and the instructor took over the controls to demonstrate the abort procedures. The instructor took the controls just prior to call for the abort. When the abort phase began, the instructor applied aft cyclic and slightly lowered the collective. The helicopter had been in a tail low attitude and started to descend into "settling with power." The instructor applied forward cyclic and lowered the collective, however the helicopter did not have sufficient altitude to level out or gain airspeed to recover before impacting the ground on the right side skid. The helicopter pivoted around about 180 degrees then rolled over onto its left side. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_2004_SEA04CA122.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 ↗