What is an Aircraft Maintenance Check?

Aircraft maintenance checks are periodic inspections performed by technicians on every commercial or civil aircraft after a defined period of time or usage. As part These procedures help determine the airworthiness of an aircraft and ensure the safety of its next flight and the crew and passengers it is carrying.

Importance of Aircraft Maintenance Checks

As an inherent responsibility part of aircraft ownership required by the Federal Aviation Administration (FAA), no aircraft operator/owner is exempted from aircraft maintenance checks. Title 14 of the Code of Federal Regulations (14 CFR) specifically states that “the owner/operator of a civil aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with FAA Airworthiness Directives (AD)”. Aircraft maintenance checks involve a series of activities, such as inspection, overhaul, reformation, defect rectification, and repair that helps ensure air transportation is as safe as possible. In a nutshell, here are 4 key reasons why aircraft maintenance checks are essential to aircraft operators:

• To prevent mechanical failures and ensure flight safety In aviation history, mechanical failures account for almost a quarter of all fatal accident causes ; the rest are due to sabotage, weather, and human error. Aircraft maintenance checks help identify hazards early on, and ensure that only the safest aircraft are utilized to guarantee the safety of the passengers and flight crew.

• To preserve the life of the aircraft and maintain a record of safe performance Aircraft are designed to operate for certain cycle limits , a determinant of the airframe’s lifespan. Through regular aircraft maintenance checks, aircraft owners can keep engines working at their best level and ensure that their safety design is sustained throughout their lifespan.

• To minimize aircraft downtime Every second is valuable in aircraft operations. By regularly maintaining engines, aircraft can suffer from less downtime and major repairs, which can benefit operators on their bottom line.

• To keep repair costs at bay Repairs are often more expensive than maintenance activities, so keeping up with a regular aircraft maintenance check schedule is beneficial as it saves operators from costly repairs.

2 Major Types of Aircraft Maintenance Checks

According to 14 CFR, aircraft maintenance checks revolve around two broad types of inspections: scheduled and unscheduled. Here are the differences between the two types of aircraft maintenance checks and the types of inspections under them:

1. Scheduled Aircraft Maintenance Checks

Scheduled aircraft maintenance checks comprise preventative maintenance activities performed according to defined intervals, as required by the Federal Aviation Regulations (FAR). Operators often develop and customize checklists (or job cards) to record deficiencies discovered during inspections. Four types of aircraft inspections are covered under this type of check, namely:

• 100 Hour Inspection Aircraft under 12,500 pounds (except turbojet/turbo propeller-powered multi-engine airplanes and turbine-powered rotorcraft) utilized for commercial operations must have undergone a 100-hour inspection within the preceding 100 hours of time in service ( FAR 91.409b ). Aircraft used for flight instructions for hire (e.g. Cessna 172 and 150), when supplied by a flight instructor, is also subject to 100-hour inspection. This inspection must also be completed by an A&P mechanic.

• Annual Inspection As per the FAA, every airplane is required to undergo an annual inspection to be legal to operate, regardless of whether they are used for hire, flight instruction, or for recreational use ( FAR 91.409a ). For the inspection to be valid, it must be accomplished according to FAR 43 Appendix D by a qualified Airframe and/or Power Plant (A&P) mechanic holding an inspection authorization (IA) within the preceding 12 calendar months.

• Progressive Inspection If an operator’s aircraft fleet is utilized heavily every year (e.g. flight school, corporate, and FBO fleets), they may opt for a progressive inspection plan to minimize maintenance downtime with the same end results. The progressive inspection is a complete inspection of the aircraft, conducted in stages, with all stages to be completed in 12 calendar months. Unlike a 100-hour or annual inspection, this plan enables more frequent but shorter inspection programs, as long as they are approved by the FAA. Although, progressive inspection plans must begin with either an annual or 100-hour inspection; inspections after the initial inspection should then follow the schedule according to the approved progressive inspection program.

• Preflight Checks Preflight checks are conducted by pilots or student pilots prior to flights to verify if an aircraft is safe for departure. With the help of a checklist, they conduct a walk-around to inspect major components of the aircraft and note if there are any defects that need immediate repair.

2. Unscheduled Aircraft Maintenance Checks

Some aircraft maintenance checks can be sudden and unforeseen, especially when there are problems found during the pre-flight, progressive, annual, or 100-hour inspection. Unscheduled aircraft maintenance checks can be corrective and preventive in nature, as they trigger the necessary immediate repairs while also helping to implement solutions in anticipation of potential faults.

What to Include in an Aircraft Maintenance Checklist

An aircraft maintenance checklist should include the following key items to ensure compliance and airworthiness of the aircraft:

• Pre-flight inspection of the aircraft’s exterior and interior, checking for visible damage, leaks, or loose components.

• Engine and system checks, including oil levels, fuel quality, and signs of leaks or corrosion.

• Avionics and instruments inspection to confirm all systems are operational.

• Landing gear inspection for defects, tire condition, and brake systems.

• Structural integrity checks for cracks, dents, corrosion, and secure fasteners on the airframe, wings, and control surfaces.

• Interior evaluation, ensuring seat belts, doors, windows, and emergency equipment are functional.

• Electrical system checks, including battery, wiring, and lighting.

• Hydraulic systems and reservoirs for proper fluid levels and secure connections.

• Compliance with regulatory requirements and documentation, such as maintenance logs and airworthiness directives.

• Scheduled and preventive maintenance tasks, including lubrication, filter changes, and cleaning.

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