Aircraft engineers may do some or all of the following:

• regularly check the engines, airframe (body of an aircraft) and mechanical systems of aircraft
• inspect aircraft, look for and diagnose faults
• repair or replace faulty parts
• replace parts that have to be changed after being in use for a certain length of time
• test parts to make sure they work
• service aircraft
• keep records of repairs
• follow set procedures
• have all work inspected and approved by licensed aircraft engineers.

Aircraft and their systems are highly varied, and aircraft engineers are not usually qualified to work on every kind of aircraft.

Aircraft engineers may choose to specialise in:

• different types (or ratings) of aircraft, such as helicopters or fixed-wing planes
• one component of aircraft, such as electrical systems or engines
• certain groups of aircraft – for example, one group consists of all unpressurised aeroplanes with fixed landing gear, weighing up to 5,700 kilograms. Some aircraft, like the Boeing 747, are so complex that they form a group on their own.

Specialising requires practical experience and exam passes. Throughout their careers, aircraft engineers may add more areas of specialisation to their licence.