All aircraft, like cars, must undergo regular maintenance in order to keep them fit for flying (though obviously cars don't fly). The consequences of a poorly maintained aircraft however are much more grave than of a poorly maintained car. In this article, I will illustrate important maintenance checks aircraft must undergo.
There are 5 main aircraft maintenance checks: Daily check and A, B, C and D checks.
The Daily check contrary to the name, does not need to be performed every day. It must however be completed after every 24-60hrs of flight time. The aircraft is visually inspected for any damage to any part of the fuselage, fluid levels are checked, the general security and cleanliness of the flight deck is looked at, and, finally, emergency equipment is checked for its presence and condition.
A Checks must be performed every 500 hours or monthly, whichever is sooner. This generally takes place overnight at the gate of an airport. The A check comprises all aspects of the Daily and also: crew oxygen system pressure, emergency lights, lubricates the nose gear retractor, parking brake pressure and uses the BITE to test the onboard electronics.
B Checks are not as common these days as they fall under fairly vague ground and checks are instead distributed between A and C. However, where B is are completed it follows a similar itinerary to A, but are a little more vigorous.
The C, with the D is known as a heavy check. The C check is an extensive check of each of the individual components of the aircraft for function and serviceability, compromising both visual checks and operational checks. The C check generally renders the aircraft out of service for 3-5 days and also incorporates each of the lower checks.
D Checks, which can take 20 or more days include all aspects of the lower checks and also consist of stabilizer attach bolt inspection, floor beam inspection and the detailed inspection of the wing box structure.