AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

Types of Aviation Maintenance Checks

As the aviation industry is highly regulated, airlines are mandated to implement continuous inspection programs regulated by the United States Federal Aviation Administration (FAA). The FAA requires each airline/operator to establish a Continuous Airworthiness Maintenance Program (CAMP) that outlines routine and detailed inspections or checks of aircraft in their fleet. Checks are particularly important to ensure that aircraft are performing optimally and are airworthy, guaranteeing that passengers reach their destinations safely.

While the FAA oversees the regulations and programs for a majority of aircraft, it is entirely up to the airline to ensure that maintenance is carried out and meets CAMP specifications. As such, aircraft have required checks at various time intervals, often referred to as flight line maintenance checks, which consist of four different types of higher-level maintenance: “A,” “B,” “C,” and “D.” The main purpose of these checks is to conduct routine and impromptu maintenance of aircraft, such as scheduling the repair of known problems, replacing items after a certain air time, and more.

Commonly known as a post-flight, maintenance pre-flight, service check, and overnight check, line maintenance checks are the most routine of all aircraft assessments. Line checks necessitate minimal tools and are usually carried out at the airport gate under the “open sky.” They happen quite often since they cover basic inspection checks and consist of examining the wheels, brakes, fluid levels, and more. Such checks ensure that the aircraft is functioning properly and safe to continue service. It is important to note that line maintenance is needed after every 24 to 60 hours of flight time, but ultimately depends on the operator of the aircraft.

The next level of checks are called “A” checks. An “A” check is performed every 400-600 flight hours, or every 200-300 flights, depending on the type of aircraft at hand. This type of maintenance is usually conducted at a hangar and takes a minimum of 10 hours to complete, but is usually determined by the services needed. In some cases, “A” checks can be performed overnight so that they do not disrupt an airlines’ schedule. Furthermore, the frequency of “A” checks varies by aircraft type, flight cycle count, and flight hours since the last check. Additionally, they often cover the general inspection of the aircraft for damage, deformation, corrosion, and missing parts.

Meanwhile, “B” checks are often carried out during the “A” check phase. For airlines and operators to maintain, repair, and overhaul an aircraft with increased efficiency, some “B” checks have been incorporated into “A” check phases. Not only does this reduce aircraft downtime, but it improves maintenance scheduling and takes better advantage of resources like hangars and test equipment. Typically, aviation professionals perform “B” maintenance checks every 6 to 8 months, and such checks take approximately 160-180 labor hours to complete. They usually consist of checking alignment, torqueing the nose landing gear spotlight, and more.

In contrast, “C” and “D” checks are categorized under “heavy maintenance,” and they are more extensive than the last two types. “C” checks necessitate the in-depth inspection of a majority of aircraft parts and can place the aircraft out of service for 1-2 weeks. This type of check requires an aircraft to be stationed at a maintenance facility equipped with the necessary space, tools, and technicians. Additionally, up to 6,000 maintenance hours are required for “C” checks. For instance, maintenance technicians will perform certain tasks like the examination of load-bearing components, checking the operation of the DC bus tie control unit, and carry out a thorough lubrication of all fittings and cables.

Lastly, “D” checks are termed “heavy maintenance visits” that occur every 6-10 years depending on the aircraft model. “D” checks consist of comprehensive inspections and repairs of the entire aircraft, including the disassembly of the airframe to check for damage and corrosion. This process usually takes anywhere from 30,000 to 50,000 hours and is conducted over a period of 4-6 weeks. During this check, the entire aircraft may be stripped down, allowing technicians to replace or refurbish different parts of the aircraft interior. Due to how extensive these checks are, most airlines will plan a “D” check years in advance.

Regardless of the maintenance check that is going to be carried out, airlines, operators, and technicians should be well aware of when such assessments should be conducted. This can eliminate the likelihood of an aircraft incident occurring and can extend the service life of your aircraft. That being said, when sourcing aircraft maintenance parts, specialized tools for repair, or various aircraft maintenance equipment, rely on Nascent Aviation.

Nascent Aviation is a leading distributor of all types of aviation tools required for aircraft maintenance operations, all of which are subjected to varying levels of quality assurance measures, tests, and verifications. Initiate the procurement process for any item in our inventory via our Instant RFQ service and see how Nascent Aviation can serve as your strategic sourcing partner!


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