The federal government of the particular country regulates the aircrafts to which they are registered or serviced. Maintenance, Repair, Overhaul (MRO) is the common and professional term which is used to describe the aviation maintenance process.
Airline Letter Maintenance Checks
Regulatory Authorities categorize the group of aviation maintenance checks in terms of the following letters: A, B, C, D and occasionally H.
- ‘A’ Check: This check is referred to performing following maintenance tasks: inspecting, changing filter, lubricating, servicing and performing any required unscheduled maintenance activity. This is performed by the Line Maintenance Department at an interval of 14 to 21 days. This check requires 20 to 40 man-hours and it is completely performed with in 8 to 12 hours.
- ‘B’ Check: In addition to all the tasks performed in ‘A’ Check, the ‘B’ Check also include any maintenance activity to be performed on any item that requires attention on the basis of the inspection. This check is also performed by the Line Maintenance Department at an interval of 60 days. It requires 40 to 80 man-hours of work to be performed. This check is completely done in 8 to 12 hours.
- ‘C’ Check: The ‘C’ Check is done to execute all the lower level inspections’ activities plus the yearly inspection to include rigging, recalibration of major systems and restoration of cabin interiors. This check is performed by the Line or Heavy Maintenance Departments at an interval of 12 to 18 months. It requires 2000 to 5000 man-hours of work to be done. This check is finished within 3 to 7 days.
- ‘D’ Check: The ‘D’ Check is done to perform the overhaul of major items such as the landing gears, the engines and the structural corrosion tasks. This task is conducted by the Base Maintenance Department at an interval of 8 to 10 years. This check requires 20 000 to 30 000 man-hours of work to be completed. It is done within 21 to 30 days.
- ‘H’ Check: The ‘H’ Check is done to deal with the issues related to corrosion in case of old aircrafts. This check also includes restoration of expected corrosion zones. This check is supported by some airlines only. It is performed by the Base Maintenance Department at an interval of 2.5 to 4 years. It requires 9000 to 12000 man-hours of work to be executed. It is complete within 7 to 14 days. (Frohne, 2007).
Types of Airline’s Scheduled Maintenance
- Routine Maintenance: This is the required maintenance per timeframe. It is set by Original equipment Manufacturer (OEM) and Federal Aviation Administration (FAA).
- Non-Routine Maintenance: This involves removing the faults encountered through scheduled maintenance downtime.
- Engineering Orders: These are the mandatory amendments and enhancements proposed by the OEM’s Engineering Department.
Types of Airline’s Scheduled Maintenance Intervals
Typically, all the commercial airlines have the following three types of Scheduled Maintenance Intervals.
- Line Maintenance: This type of maintenance is performed while the aircraft is being parked at the gate of the airport. During this process, the issues raised by the aviator are analyzed and solved through inspection and servicing, respectively. The availability is dependent on the decision of the Line Mechanic
- Mid-Visit Maintenance: The group of maintenance activities involved here are executed almost after every 4 years, 8000 cycles or 25000 hours.
- Heavy Maintenance: This is done after every 8 years, 13000 cycles or 40 000 hours. This is done to accomplish heavy structure renewal. (Frohne, 2007).