When Should You Replace Brake Discs, Bolts, and Actuators?

Modern aircraft are engineering marvels, heavy in weight and composed of thousands of parts, yet they are capable of traversing long distances in the air with ease. From structural bolts to advanced actuators and high-stress brake discs, every component plays a vital role in this capability, making it necessary for operators to maintain the airworthiness and health of every assembly through routine inspection and maintenance practices.

Among the myriad of aircraft parts that are regularly cared for during service, brake discs, bolts, and actuators are high-attention parts as a result of enduring high mechanical and environmental stress during typical operations. Although they may be less prevalent in discussion than engines or avionics, understanding when and how to replace these components is crucial to upholding airworthiness and safety standards. As such, be sure to read on as we provide a focused overview of these components, covering their basic roles, common signs of degradation, and best advice for standard replacement protocols.

Brake Discs

Aircraft brake systems are necessary for generating the stopping power for slowing down an aircraft during landing or taxiing, such assemblies being subject to extreme stress during typical use.For example, discs experience high temperatures, repeated frictional loads, and environmental exposure, all of which makes them susceptible to wear over time.

Common Causes of Brake Disc Wear

1. Friction and heat from regular landings.
2. Oxidation and corrosion resulting from environmental conditions.
3. Foreign object damage (FOD) from runway debris.
4. Improper brake usage, such as dragging or asymmetrical application.

When to Replace Brake Discs

Replacement schedules will generally vary by aircraft model, brake disc manufacturer, and usage intensity, though several telltale signs will indicate that replacement may be required.

• Disc Thickness Below Minimum Tolerance: Every disc has a manufacturer-specified wear limit, where levels below minimum tolerance levels will lead to issues
• Visible Cracks or Scoring: Deep grooves or surface fractures compromise part integrity.
• Discoloration from Overheating: Bluish hues or warping generally suggests thermal degradation.
• Uneven Wear Patterns: Uneven wear patterns can lead to imbalanced braking forces and compromised control.

Useful Maintenance Practices

To uphold the lifespan and performance of brake discs, it is important to conduct regular inspections after a specified number of landings or flight hours, use non-destructive testing (NDT) methods to detect internal flaws, and carry out replacements as per the guidelines laid out in OEM maintenance manuals.

Bolts

Bolts are among the most frequently used fasteners in aircraft, often being tasked with securing major structural components, systems, and assemblies. Despite their small size and seemingly simple design, bolts handle significant mechanical loads and secure many flight-critical systems. As a result, their failure can potentially result in safety risks and hazards.

Common Reasons for Bolt Wear

1. Vibrational forces that cause loosening and damage.
2. General fatigue stress from cyclic loading.
3. Corrosion from moist or chemically reactive environments.
4. Damage from improper torque during installation.

When to Replace Bolts

Aircraft maintenance professionals are trained to inspect bolts for common indicators of damage, with the following being signs that a replacement may be necessary:

• Visible Rust or Pitting: Rust and pitting are both signs of corrosion damage, often necessitating part replacement.
• Thread Deformation: Bolt threading is what holds assemblies together, so deformation is a concerning sign.
• Other Major Issues: Looseness, bolt elongation, fractures, and shearing are all major concerns that may require repairs or replacements.

Useful Maintenance Practices

It is always best to use OEM-specified replacements to maintain structural integrity, though proper alternatives may be fine in many cases. During installation, be sure to apply proper torque values using calibrated tools to avoid over-tightening or under-tightening. Additionally, use locking compounds or safety wire where applicable when loosening is a concern.

Actuators

Actuators are devices that convert electrical, hydraulic, or pneumatic energy into mechanical movement, commonly being found in aircraft systems including landing gear, flight control surfaces, thrust reversers, and cargo doors.

Common Causes of Actuator Wear

1. Mechanical fatigue from repeated use.
2. Hydraulic leakage or pressure loss.
3. Seal failure or contamination.
4. Electrical motor wear in electric actuators.

When to Replace Aircraft Actuators

The lifespan of an actuator can vary widely depending on its design and application. Nonetheless, replacement should be considered when the following symptoms appear:

• Reduced or erratic movement in associated control surfaces or mechanisms.
• Abnormal noises occurring during actuation (e.g., grinding or clicking).
• Hydraulic fluid leakage occurring near ports or seals.
• Failure of actuators to maintain position under load.

Useful Maintenance Practices

To best maintain actuators, always perform functional tests during routine maintenance intervals, as well as monitor hydraulic pressure and response times for anomalies. From there, one should replace actuator seals, bearings, or the full assembly based on diagnostic findings and flight hour limitations, following OEM servicing manuals and airworthiness directives for exact replacement instructions.

A Trusted Source for Maintenance Components: Veritable Aviation

At ASAP Semiconductor, we understand the importance of having timely access to reliable parts that support aircraft maintenance and safety. Through our website, Veritable Aviation, we proudly offer access to a broad inventory of high-quality maintenance components, which includes brake discs, fasteners, actuators, and other in-demand aerospace products.

Whether you are seeking replacements for routine maintenance or addressing a critical AOG requirement, Veritable Aviation simplifies sourcing and fulfillment so that you can keep your operations running efficiently. All purchases made on the website are also handled by ASAP Semiconductor staff, meaning customers will be treated to hands-on service through each step. With this in mind, choose Veritable Aviation for all your maintenance part needs and experience the difference that expert sourcing and tailored service can make.