A maintenance check flight (MCF) is a flight of an aircraft with an airworthiness certificate or with a permit to fly which is carried out for troubleshooting purposes or to check the functioning of one or more systems, parts, or appliances after maintenance, if the functioning of the systems, parts or appliances cannot be established during ground checks.
A MCF is carried out in any of the following situations:
a) As required by the aircraft maintenance manual (AMM) or any other maintenance data issued by a design approval holder being responsible for the continuing airworthiness of the aircraft;
b) After maintenance, as required by the operator or proposed by the organisation responsible for the continuing airworthiness of the aircraft;
c) As requested by the maintenance organisation for verification of a successful defect rectification; or
d) To assist with fault isolation or troubleshooting.
Several accidents and incidents have occurred involving aircraft that had just undergone incomplete or inadequate maintenance or during flights conducted to verify adequate maintenance of aircraft. In 2017, the European Union Aviation Safety Agency (EASA) issued opinion No 01/2017 to mitigate the risks linked to MCFs because it found that the issue of MCFs was not sufficiently addressed in the EASA AIR OPS regulations. The opinion proposed establishing safety requirements to adequately select pilots and apply procedures for MCFs while distinguishing between MCFs with complex motor-powered aircraft and MCFs with other-than-complex motor-powered aircraft. At the end of the rulemaking activity, MCF requirements were embedded in EASA AIR OPS Part-NCO and Part-SPO.
Operators conducting the higher risk category of these MCFs with complex motor-powered aircraft (under Part-SPO) are required to develop their own procedures and ensure thorough coordination between the operation, the continuing airworthiness management organisation (CAMO) and the maintenance organisation concerned.
Before conducting a maintenance check flight, the aircraft operators are required to determine the applicable level of the MCF as follows:
a) ‘Level A’ MCF for a flight where the use of abnormal or emergency procedures, as defined in the aircraft flight manual, is expected, or where a flight is required to prove the functioning of a backup system or other safety devices.
b) ‘Level B’ MCF for any MCF other than a ‘Level A’ one.
Non-commercial operations (NCO)
Part-NCO governs MCFs with other-than-complex motor-powered aircraft.
In addition to the standard considerations before a typical flight (weather, aircraft weight and balance, pre-flight inspection, checklists, etc.), the pilot is required to inform air traffic control of the particular MCF, if needed, agree on the appropriate airspace, understand the airworthiness status of the aircraft, assess the complexity of the flight and develop appropriate strategies to mitigate potential risks.
When selecting a flight crew member for a MCF, the operator is required to consider the aircraft complexity and the level of the maintenance check flight. The pilot-in-command has the role to identify the need for additional crew members or task specialists, or both, before each intended maintenance check flight, taking into consideration the expected flight crew member or task specialist workload and the risk assessment.
Specialised operations (SPO)
Part-SPO governs MCFs with complex motor-powered aircraft.
Operators conducting a Level A maintenance check flight are required to describe those operations and associated procedures in the operations manual or in a dedicated maintenance check flight manual, update the manual when necessary, inform all affected personnel of the manual and of its changes that are relevant to their duties and provide the competent authority with the manual and its updates.
The operators are also required to establish procedures to identify the need for additional task specialists. For a Level A maintenance check flight, the operators are required to define in their manuals the policy for other persons on board. In addition, a task specialist or additional pilot is required in the flight crew compartment to assist the flight crew members, unless the aircraft configuration does not permit it or the operator can justify, considering the flight crew members workload based on the flight programme, that the flight crew members does not require additional assistance.