Once the aircraft is certified and in operation with the airlines, engines are frequently inspected once the engines have been installed on the wing. At the conclusion of these inspections or after engine replacement, the engines are tested on the wing at various power levels.
Engine tests on-wing are conducted for various reasons and include tests such as:
- Power assurance check, to verify that the engine is capable of producing the required thrust;
- Vibration and balance checks to check and, if necessary, balance the engine rotors;
- Oil and fuel system checks;
- Leakage checks to verify that all systems are free of leakage.
The engine test on-wing are conducted in the open field or in the vicinity of the hangar.