How often do commercial aircraft go in for maintenance?

ABC Check System

Aircraft maintenance checks are periodic inspections that have to be carried out on all heavy and light aircraft after a certain amount of usage or flying hours. It is obvious that the more the aircraft is flown, the more frequently it will need servicing. This is why manufacturers specify 'flight hours' rather than a timeframe for maintenance checks.

The check system includes A check and B check for minor investigations. C check and D check for major or heavier inspections. Aircraft operators are allowed to conduct lighter checks on their own, but C and D checks are expected to happen at the locality of a certified aircraft welding company.