Aircraft maintenance (MRO) is the work done on an aircraft between flights to keep it airworthy, and the software that records it. MRO stands for maintenance, repair and overhaul. An airliner may fly several flights a day for 25 years or more. Between flights, engineers check it and sign it off as safe to fly.
The checks come at different intervals. A short walk-round check is done before flights. A longer check is done at night every few days. A heavy check, in which large parts of the aircraft are opened and inspected, happens after several years of flying and keeps the aircraft on the ground for weeks.
An aircraft may fly only if it is airworthy, which means fit to fly by the regulator's rules. In India the regulator is the DGCA, the Directorate General of Civil Aviation. Three rules shape the software. First, many parts have a life limit: each one must be replaced after a set number of flying hours, or a set number of cycles, where one cycle is one take-off and one landing. Second, every inspection, repair and replacement must be recorded, and the records stay with the aircraft for its whole life. Third, an aircraft with incomplete records can be grounded, and it is worth much less when sold. This is the same idea as traceability. The software that keeps the records is aviation MRO software.
Take the maintenance of one aircraft at Hyderabad airport. An engineer gets a job to replace a worn part. Maker's manuals run to thousands of pages, so aircraft technical publications software shows the engineer the right procedure at the latest version. The engineer does the job, logs it, and signs the aircraft off. Regulators still require a person to sign off each job, even where AI drafts the paperwork, in the way described under the model drafts, a person approves.
The pilots have their own tools. They load the charts, the flight plan and the weather on a tablet, the electronic flight bag. They train and are tested at regular intervals in a flight simulator.
Two more things tie these pieces together. The first is safety certification, which every part, procedure and engineer must satisfy. The second is a digital thread of records that connects the maker's design data to the airline's maintenance records.