Aircraft maintenance program ensures that the inbuilt reliability and safety divulged to an airplane through its structural framework is sustained. It offers a chance to restore the reliability and safety levels when deterioration occurs.
The aircraft goes through actions like repair, servicing, inspection, overhaul, modification, and determination of its performance level. The things that impact an aircraft the most are deterioration with age like corrosion, wear & tear, and fatigue. There are even possible chances of failure like excessive mechanical loads and tire burst.
See here to learn how aircraft control gets maintained. On Flight Literacy Blog, you can read about interesting facts and features associated with the aviation sector. It helps new pilots to get educated on relevant topics. Any type of airplane maintenance program gets developed and evolved based on previous experience related to similar structures, materials, components, or engines. Hangar environment is not required but aircraft maintenance is necessary to –
- Check the aircraft’s airworthiness, which is vital for the safety of everyone traveling aboard.
- Keep the aircraft in better performance, which is important to an operator.
- Increase the asset value, which is crucial for the lessor or owner.
The program includes a blend of corrective and preventive measures. Precautionary tasks ensure that chance failures don’t go undetected. An inspection helps to monitor the deterioration level.
Line or light maintenance
It includes daily checks or pre-flight checks for fluids or failure overhaul. It includes –
- Defect rectification
- Component replacement
- Visual inspection to detect above failures and schedule maintenance
- Minor adjustments and repairs that don’t need extensive disassembling
Any kind of maintenance conducted before the flight to ensure that the aircraft is suitable for an intended flight can be defined as light or line maintenance. The tasks that fall outside the above criteria are regarded as base maintenance.
Heavy or base maintenance
Heavy maintenance comprises tasks that are long-lasting and more in-depth but performed less frequently. C & D checks include the inspection of systems, engines, and airframes. Identified defects get removed. If there is a need for a technology upgrade it gets done. Cabin painting and reconfiguration are also performed under heavy maintenance.
Shop or workshop maintenance covers the component care removed from the airplane like seats, engines, APU, etc.
The maintenance intervals get defined according to some specific criteria depending on the identification of damage and prediction of failure.
- Hard time is performed at periods associated with servicing manual like several cycles, calendar time, number of landings, etc. It is a preventive process, where the item’s deterioration status is restricted to a tolerable level.
- On-condition is an inspection that reveals a need to do maintenance. It is a preventative process, where the item gets tested or inspected at a specified period and removed before it fails.
- The condition monitoring process is automated. Items information gets collected, scrutinized, and interpreted continuously to determine whether to execute corrective procedures or not.
Maintenance interval units
- FH or Flight Hours – For parts that are consistently in operation like the electric generators and fuel pumps.
- Cal or Calendar Time for parts that are operating or not like structure corrosion or fire extinguishers.
- FC or Flight Cycles for machines or components that operate once or twice during a flight like brakes, air starters, landing gear, and hull pressurizations.
- Operating hours are for parts that are independent of FC or FH like APU operations.