Maintaining the safety of your airport’s hangar doors is not just about compliance—it’s about protecting personnel, aircraft, and infrastructure. A neglected, malfunctioning, or failing hangar door can result in serious injury or loss of life. Regular inspections, proactive maintenance, and vigilance in daily operations can help prevent failures and provide for a smooth and safely operating hangar door. Whether you own or lease a hangar, understanding and implementing these best practices—along with scheduling professional maintenance annually—will contribute to a safer and more efficient aviation environment.
Inspection frequency
Routine inspections are crucial for identifying wear and potential failures before they become hazards. Professional maintenance should be performed annually on each hangar door. If you lease a hangar, be sure to check your lease agreement to confirm maintenance responsibilities.
- Daily/before each use: Operators should perform a visual inspection, checking for frayed cables, misaligned pulleys, unusual noises, or any visible damage. Cables should be inspected before each use to confirm they are in good condition. Many hangar doors have mechanisms located in the attic space that cannot be seen from the ground, making regular inspections of these mechanisms essential to ensure they remain in proper working order. For hydraulic doors, this includes checking for leaks around cylinders, hoses, and fittings, as well as monitoring fluid levels for any signs of pressure loss.
- Quarterly: Owners or maintenance personnel should conduct a more thorough assessment, confirming proper alignment and lubrication and checking for leaks or loose components. At a minimum, they should check the door alignment, lift points, keyways, set screws, and tension. In addition, hydraulic setups should be evaluated for system pressure stability and any signs of deterioration in hoses or seals. Ensuring the pump operates correctly is also important.
- Annually: A certified technician should inspect key components such as gearboxes, pulleys, shafts, cables, rollers, keyways, set screws, and motor assemblies on an annual basis. For systems relying on hydraulic power, this inspection should include a thorough review of cylinders, pumps, valves, and seals to catch early signs of wear. Hangars storing critical aircraft, such as medical emergency aircraft, should undergo professional inspections every 6 to 12 months.
Common signs of wear and failure
Identifying issues early can prevent failures that may cause injury or damage to aircraft and equipment. Watch for these key signs:
- Frayed or kinked cables—If cables show wear, they must be replaced immediately.
- Unusual noises—Grinding, squeaking, or rattling could indicate problems with hinges, pulleys, or bearings that could lead to mechanical failure.
- Uneven movement—If the door opens or closes at an angle, it may be misaligned or have uneven cable tension, increasing the risk of collapse.
- Leaking fluids—Hydraulic doors may show signs of leakage in the fluid systems, indicating worn seals or failing components that could compromise the functionality.
- Rust and corrosion—Any signs of rust on chains, pulleys, or cables should be addressed immediately to prevent component failure.
Good practices for hangar door maintenance
Proper maintenance extends the lifespan of hangar doors and improves safety.
Bifold doors
- Regular lubrication—Lubricate bearings, hinges, chains, and drive sprockets per manufacturer recommendations to prevent rust and seizing. Use lithium grease for hinges and bearings and avoid over-lubricating, as excess grease can attract dust and debris.
- Gearbox maintenance—Check gear oil levels and replace the oil according to manufacturer specifications. Low or contaminated oil can lead to overheating and gear damage, increasing failure risk.
- Cable, pulley alignment, keyways, and set screws—Check that pulleys are aligned properly to prevent excessive wear and potential cable failures that could result in sudden door drops. Vibrations can also loosen the keyways, so regular inspection of keyways and set screws is recommended.
- Strap lifts and strap latches—Install a lift strap conversion kit and strap latch conversion to eliminate cables, cable clamps, and pulleys, reducing potential points of failure.
- Backup safety systems—Consider installing:
- Brakes on motors to help hold the door in place once stopped. However, they do not prevent movement in the event of a failure.
- Counterbalance systems and redundant safety mechanisms to help mitigate uncontrolled movement.
- Safety micro-switches and failsafe lift mechanisms to enhance safe operation by detecting malfunctions before they become hazards.
Hydraulic doors
- Regular lubrication—Ensure hydraulic cylinders, hinges, and pivot points are properly lubricated to reduce wear and extend service life.
- Hydraulic system maintenance—Check hydraulic fluid levels regularly, replacing or filtering fluid per manufacturer recommendations. Contaminated or low fluid levels can cause sluggish performance and system failures.
- Backup safety systems—Consider installing:
- Hydraulic pressure relief valves to help control movement and prevent dangerous over-pressurization.
- Velocity fuses to provide critical protection by locking hydraulic flow if a sudden pressure loss occurs, preventing uncontrolled descent.
- Restrictors, commonly found in older hydraulic doors. Restrictors are sometimes used by manufacturers to slow the descent of a door in the event of a failure. However, they do not prevent the door from falling if a hose or line breaks. While they provide some level of control, they are not a fail-safe solution.
Many hydraulic door systems now incorporate auto shut-off features and redundant safety mechanisms to improve reliability and prevent sudden drops. For older doors, evaluating available safety upgrades can help enhance reliability and reduce the risk of sudden failures.
General safety considerations
- Immediate response to failures—If a gearbox or pulley fails, disconnect power to the door immediately, cease operations, and arrange for repairs before attempting to move the door manually. Never walk under an operating door—if failure occurs, gravity may cause the door to drop.
- Increased signage—Adding more signage around the hangar door area can help caution personnel and visitors about door operations.
- Warning stickers for guests—Placing warning stickers in visible locations helps alert visitors unfamiliar with hangar door operations to potential hazards.
Hangar door suppliers and maintenance services
The following hangar door supply companies provided information for this article. These companies may be able to provide or advise on professional inspections of hangar doors.
—Melissa Underwood is a senior aviation planner with SEH.
