Contemporary airplane parked in a hangar.
Matthew Bean

If you own an aircraft, you need to understand aircraft maintenance. Aircraft are complex, massive machines that require routine maintenance to ensure safety. But what exactly does this entail? In this guide, you can learn everything you need to know about aircraft maintenance.  

Why is Aviation Maintenance Performed? 

Aviation maintenance ensures safety. Just like a car, aircraft require routine maintenance to identify and fix issues. Without regular maintenance, unidentified mechanical problems could become disastrous. 

More specifically, the International Air Transport Association (IATA) defines maintenance as, “actions required for restoring or maintaining an aircraft, aircraft engine or aircraft component in an airworthy and serviceable condition.” They add that this includes “repair, modification, overhaul, inspection, replacement, defect rectification and determination of condition.” 

Aviation maintenance is also essential to ensure availability, value, and airworthiness. 

Aircraft maintenance, King Air 200.

What is airworthiness?

The primary objective of aviation maintenance is to ensure airworthiness. Airworthiness is the process of keeping an aircraft flying in a condition where it performs as intended by the manufacturer, including meeting all regulations and compliance standards. Upon satisfying the minimum acceptable requirements, eligible companies receive certifications from authoritative bodies.

Airworthiness also embodies the general process of reducing risk and danger while flying. It is a necessary process because it reduces equipment-induced accidents. 

Who can perform maintenance?

As you can imagine, the guidelines and processes related to maintenance are complex, requiring a trained professional, as outlined in the aviation maintenance technician handbook. 

In the United States, the Federal Aviation Administration (FAA) regulates the profession, and only those who complete the necessary training receive the Airworthiness Certification. The organization currently houses over 1,300 safety professionals. 

In addition, anyone with a pilot’s license is able to perform preventative care. However, they must be the owner or operator of the aircraft. This rule does not apply to commercial aviation. In this case, only certified mechanics and businesses can perform maintenance. Finally, any minor or major items identified during preventative maintenance require a technician’s signature, regardless of the aircraft type. 

The Best Aircraft Maintenance Company

Southern Air Custom Interiors offers jet maintenance services, including custom interior design, annual maintenance, aircraft repairs, avionic sourcing and installation, and much more. Southern Air’s staff has over 100 years of experience handcrafting interiors. They work on Cessna, Beechcraft, Mooney, Gulfstream, and many other models. Overall, Southern Air is a trusted business in the aircraft maintenance industry.  

Types of Aircraft Maintenance

Not all aircraft are created equal, and each model has different needs at various stages of life. For this reason, there are different types of aircraft maintenance. Most aircraft incur each type at some point in their lifespan. Let’s explore them further below. 

Service Maintenance

Aircraft that fly regularly require regular care. An indispensable part of service maintenance is record-keeping and logbook upkeep.  Aircraft operators log all activity and issues, and monitoring these records helps track and resolve aircraft problems. The blanket term for any maintenance is record-keeping service maintenance.

Line Maintenance

As the name indicates, line maintenance is anything flight line personnel and the crew can perform. Line maintenance is relatively simple compared to other aircraft maintenance. It is also the type of aircraft maintenance that occurs most frequently. 

Pre-flight and post-flight checks and inspections fall under this category, including visual inspection, replacement of easily accessible components, and troubleshooting on the ground or in flight. Usually, line maintenance happens quickly unless more significant issues come to light during the process.

Base Maintenance 

Base maintenance is a more intense version of line maintenance. It is more time-consuming and takes an in-depth look at the aircraft. Thorough inspections, overhauls, improvements, and modernization programs fall under this category. All of these processes occur at the base level. It requires personnel, facilities, and specialists who are not necessarily available in flight. Any corrective work required by governing bodies falls under this category too. 

Depot Maintenance

Depot maintenance is also known as workshop maintenance. This kind of maintenance involves removing specific parts from an aircraft sent to a specialized facility for maintenance and repair.  Aircraft engines routinely undergo this process. They require regular overhauling to stay airworthy. Depending on the airport, depot maintenance may be able to occur on-site. 

Aircraft maintenance, rand 5.

Inspections and Intervals

Regulatory bodies outline mandatory preventive inspections, which include guidelines for aircraft maintenance and ensuring airworthiness. As mentioned above, logging and record-keeping of all inspections chronicle the life of the aircraft.  Records kept with a list of aircraft maintenance manuals are valuable resources for any owner/operator. These practices, called inspections and intervals, are developed over time using historical knowledge and expert input. 

What are intervals?

Intervals are the periods where aircraft maintenance occurs. Choosing an interval depends on the ability to detect wear and tear. The objective is to catch it before it causes malfunctioning or complete failure. Intervals fall into three subsections: hard time, on-condition, and condition monitoring. 


Performed periodically to inspect and test the component in question, the purpose of this interval is to assess whether a component can continue to function based on its current state. It is a preventive measure. The goal is to identify signs of failure early and fix the problem accordingly. 

This practice typically covers surface-level components of the aircraft. Going deeper may result in the dismantling of the craft, which is not necessary.

Condition Monitoring

This type of interval is a newer standard, and unlike the others, it’s fully automated. Sensors inside the aircraft components continuously generate status reports. The information transmits to a computer located in or out of the aircraft. Using these status reports, personnel can fix issues as they arise. 

Hard Time

Hard time intervals get their name from the fact that they occur at a set, specific time. Usually, this is an actual calendar date. Or, it could be a measurable limit, such as flight hours or other similar cycles. This kind of maintenance interval is common among older aircraft and is also helpful in assessing components that are challenging to inspect without a complete teardown.

Hard time intervals are a safety measure. For this reason, they must guarantee the aircraft will operate safely between each inspection. Unfortunately, this means the timing of repairs will never be perfect. Sometimes part replacement or overhauls happen too soon or too late. The latter is more severe since it could cause accidents or issues while flying. 


Inspections occur around on-condition and hard time intervals. These processes are not automated, and execution is the responsibility of personnel. Inspections are not scheduled but happen on an as-needed basis as events arise, such as a hard landing, overload, collision, or other similar incidents. The goal of these inspections is to identify why the aircraft struggled. Corrective action occurs where required. 

Aircraft must undergo annual inspections every 12 calendar months and are the responsibility of a qualified mechanic, certified repair workshop, or manufacturer. If it is a commercial aircraft, an additional inspection happens every 100 flight hours. Commercial aircraft use includes passengers, cargo, pilot training, and much more. 

The pilot in command, PIC for short, holds the responsibility for the airworthiness. They have this responsibility for as long as they are in the role and must remain informed of regulations. The PIC must hold the aircraft registration documents, valid airworthiness certificate, and an approved document containing operational limitations, usually the flight manual or the pilot handbook. In addition, PICs have the authority to abort a flight if issues arise within the aircraft. 

Aircraft maintenance, Beechcraft 58 Baron

Special Cases

Generally speaking, aircraft maintenance stays on a set schedule. Although, there are special cases where aircraft may require more attention. Below are two circumstances. 

The Minimum Equipment Requirement

Sometimes pilots find themselves in a position where their equipment fails, which could happen mid-flight, or in a location where they cannot resolve the problem. Depending on the specific circumstances, the pilot may be able to fly the aircraft until suitable repairs are possible. Of course, this is at their discretion using their expertise. 

The determining factor is whether the system’s current state matches the minimum equipment requirement or list. There are restrictions, and this information is in the aircraft manual, which details the systems and components that must be working to achieve safe operations. Using this data, the pilot can determine if a flight should occur or not. 

How to Care for an Older Aircraft

Most airworthiness processes and routines ensure the safety of aircraft. However, older aircraft may have unique maintenance requirements. The two most prevalent issues in older aircraft are electrical and structural wear. More specifically, the corrosion and structural exhaustion.

The load-bearing elements of older aircraft undergo regular inspection to ensure safety. The main thing to look for is cracks and corrosion. Fortunately, these processes are becoming less intrusive, time-effective, and cheaper over time. The necessity of these processes varies depending on the aircraft and age. 

Electrical problems and related maintenance can be a more significant challenge for aircraft. Many old aircraft do not have wiring replacements nor detailed inspections in mind when constructed. Identifying these issues is difficult as a result. Even with an identified problem, fixing the replacement can be challenging if it is not readily available. Modernization programs often include complete overhauls of wiring systems making future maintenance more practical.  However, this is expensive for the owner. Even if they can afford it, the investment is not always worthwhile for an older aircraft. 

Maintenance and Flying

Maintenance and flying go hand in hand. Since aircraft are complex machines, they require attention to ensure safety and airworthiness. The next time you’re on a plane, remember all the work that goes into flight. If you own an aircraft, consider reading up on maintenance to promote longevity.

If you are an owner or operator who would like to access aircraft maintenance services, check out Southern Air Custom Interiors. They perform all types of aircraft maintenance. In addition, they can help you enhance the experience of flying through custom interiors and exteriors. 


Matthew Bean

Sales and service specialist for Southern Air. Providing guidance and scheduling to business owners across the world on refurbishing and upgrading their aircraft

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