What are the best practices and standards for landing gear maintenance and inspection?

1 Design Requirements

The design of landing gear depends on various factors, such as the type, size, and mission of the aircraft, the runway conditions, the environmental conditions, and the regulatory standards. Some of the main design requirements for landing gear are strength, durability, reliability, weight, drag, noise, and cost. The landing gear must be able to withstand the loads and stresses imposed by the aircraft during takeoff, landing, taxiing, and parking, as well as the effects of corrosion, fatigue, wear, and damage. The landing gear must also be compatible with the aerodynamics, performance, and stability of the aircraft, and minimize the impact on fuel consumption, emissions, and noise. Moreover, the landing gear must comply with the safety and certification standards set by the authorities, such as the Federal Aviation Administration (FAA) in the US or the European Aviation Safety Agency (EASA) in Europe.

2 Inspection Methods

Inspection of landing gear is a vital part of the aircraft maintenance program, as it helps to detect and prevent potential failures, defects, or malfunctions that could compromise the safety and performance of the aircraft. Inspection methods can be classified into two categories: visual and non-destructive. Visual inspection involves checking the external condition of the landing gear components, such as the tires, wheels, brakes, struts, shock absorbers, actuators, hydraulic lines, electrical wires, and sensors, for any signs of wear, damage, leakage, corrosion, or cracks. Visual inspection can be done by the pilots, the ground crew, or the maintenance personnel, depending on the frequency and level of detail required. Non-destructive inspection (NDI) involves using advanced techniques, such as ultrasonic, radiographic, eddy current, or magnetic particle testing, to examine the internal structure and integrity of the landing gear components, especially the critical parts that are prone to fatigue or stress cracking. NDI can reveal hidden defects or flaws that are not visible to the naked eye, and can be performed by qualified technicians using specialized equipment and procedures.

3 Common Defects

Landing gear is exposed to a variety of stressors and damage, such as high loads, impact forces, vibration, friction, temperature changes, moisture, dirt, and foreign objects. Common defects that can affect landing gear include tire wear or damage due to contact with the runway surface or debris; wheel damage or corrosion due to impact forces or environmental factors; brake wear or damage due to friction or thermal stress; strut or shock absorber leakage or damage due to hydraulic fluid loss or seal failure; and actuator or hydraulic system malfunction due to fluid contamination or electrical fault. Tire wear can reduce traction and load-bearing capacity, wheel damage can compromise structural integrity and balance, brake wear can reduce braking efficiency and performance, strut leakage can impair shock absorption function, and actuator malfunction can prevent proper extension/retraction of the landing gear. All of these issues increase the risk of tire burst/failure, wheel imbalance, brake fire/failure, and landing gear failure/emergency.

4 Repair Techniques

Repair of landing gear is a complex and specialized process that requires skilled personnel, adequate equipment, and strict procedures. Repair techniques can vary depending on the type, extent, and location of the defect, as well as the manufacturer's recommendations and the regulatory standards. Generally speaking, tire replacement or repair may involve patches, plugs, or vulcanization; wheel overhaul or repair may involve welding, grinding, polishing, or coating; brake overhaul or repair may involve cleaning, lubricating, adjusting, or replacing parts; strut or shock absorber overhaul or repair may involve refilling, resealing, testing, or replacing parts; and actuator or hydraulic system overhaul or repair may involve flushing, bleeding, checking, or replacing parts. All repairs must meet the specifications and requirements of the aircraft.

5 Here’s what else to consider

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