NTSB CAROL · Event
Event WPR21LA323
Registry · N8029G
FAA Aircraft Registry record.
Make / Model
CESSNA 177RG
Year of manufacture
1970 · 51 years old at event
Engine
LYCOMING IO-360-A1B6D (200 hp)
Seats / Engines
4 seats · 1 engine
Last airworthiness date
19710107
ADS-B equipped
Yes — Mode-S AAECE5
Registrant of record
LEWIS GARY DON
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
The failure of the nose gear hydraulic flex line, which resulted in a loss of hydraulic fluid which prevented the main landing gear from fully extending and locking into place during landing.
Factual narrative
On August 15, 2021, about 1457 mountain daylight time, a Cessna C177RG, N8029G, was substantially damaged when it was involved in an accident at Albuquerque International Sunport Airport (ABQ), Albuquerque, New Mexico. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, shortly after departure from St. Johns Industrial Air Park (KSJN), St Johns, Arizona, the airplane did not perform as expected. The pilot said that he noticed that the main landing gear did not completely retract, so he diverted to ABQ. Despite multiple attempts to cycle the landing gear, which included utilizing the emergency landing gear extension procedures, he was able to extend the nose landing gear, but he was unable to obtain a positive down and locked indication on the main landing gear. As fuel levels decreased, the pilot elected to land the airplane with the main landing gear in the retracted position. Postaccident examination of the airplane by a Federal Aviation Administration inspector revealed that hydraulic fluid on the undercarriage of the airplane behind the nose landing gear wheel well and the fluid level for the landing gear power pack indicated empty. Hydraulic fluid was added to the landing gear power pack and a landing gear swing test was performed. The landing gear extended but would not retract. The nose landing gear up hydraulic flex line showed signs of leakage. The hydraulic flex line was disconnected, and pressure tested with 200 ft pounds of nitrogen. A leak in the hydraulic flex line was identified near the top of the line, but well below the fitting. During normal operation, the hydraulic flex line is pressurized to about 1,500 ft pounds. No issues were noted with the emergency landing gear extension system. A review of the airplane’s maintenance records could not determine the age of the landing gear hydraulic flex line or if any maintenance had been performed on the landing gear hydraulic flex line. The pilot reported that, shortly after takeoff, the airplane was not performing as expected. He observed that the main landing gear did not fully retract so he diverted to a nearby airport. Despite multiple attempts to cycle the landing gear, which included utilizing the emergency landing gear extension procedures, he was able to extend the nose landing gear, but he was unable to obtain a positive down and locked indication on the main landing gear. As fuel levels decreased, the pilot landed the airplane with the main landing gear in the retracted position. A postaccident examination of the airplane revealed hydraulic fluid on the undercarriage of the airplane behind the nose landing gear wheel well. The nose landing gear up hydraulic flex line showed signs of leakage. The hydraulic flex line was disconnected, and pressure tested with 200 ft pounds of nitrogen. A leak in the hydraulic flex line was identified near the top of the line, but well below the fitting. It is likely that the identified leak in the hydraulic line led to a loss of hydraulic fluid and did not allow the main landing gear to extend and lock into place. As a result, the pilot made a gear up landing on the runway. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- — Aircraft-Aircraft systems-Hydraulic power system-(general)-Failure
- — Aircraft-Aircraft systems-Landing gear system-Main landing gear-Inoperative
Verbatim from NTSB's published report. Source file
NTSB_2021_WPR21LA323.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 (maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA)
From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains incon…
- Semantic Scholar 2025 · Article (Applied Sciences)
Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Just Culture in Aviation: A Metaphorical Study on Aircraft Maintenance Students
Just Culture, a sub-dimension of safety culture, has been a prominent and debated topic in aviation safety in recent years.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Performance PRISM: A Comprehensive Framework For Performance Measurement In Aircraft Maintenance
Aircraft maintenance is governed by rigorous safety requirements and high operational complexity, demanding robust performance measurement frameworks to ensure optimal maintenance practices.
Browse the full corpus — academia portal ↗