Maintenance Check Flights

ESPN-R launch Maintenance Check Flight (MCF) Manual and risk assessment guidelines to help operators, CAMOs and Maintenance Organisations make MCFs safe. 

• Download the sample MCF Manual and Risk Assessment at the bottom of the page. 

Introduction

When we talk about safety, we generally think of revenue flights such as a Commercial Air Transport (CAT), Special Operations (SPO) Aerial Work, Search and Rescue (SAR), Helicopter Emergency Medical Service (HEMS) flights or as recreational flights. There is another type of flight that deserves your attention and discussion, Maintenance Check Flights (MCFs). A wide range of safety experts from the European Safety Promotion Network – Rotorcraft (ESPN-R) have got collected all the key information of MCFs – at the bottom of the article you can download and use the sample MCF Operational Manual and Risk Assessment Guidelines.

Understanding more about Maintenance Check Flights

MCFs are post-maintenance flights carried out for troubleshooting purposes or to check the functioning of one or more systems (system functionality, recording parameters, etc.), parts or appliances, if the functioning of these cannot be established during ground checks. MCFs are in majority easy flights: read gouges and record numbers, verify that flight controls work properly, check hydraulic system pressure stability or check (“feel”) if vibrations are acceptable. But MCFs can be more demanding: entering an autorotation to check rotor speed or flying close to Vne (Velocity not to exceed) to check if the aircraft is behaving as expected, for instance. This article and the material developed by the ESPN-R Team Ops and SMS will help you to maximise the safety of your MCFs.

What if?

Most MCFs are uneventful but if you are an MCF pilot, are you aware that the systems you check are potentially more likely to fail during an MCF than in a normal flight? Do you know what can go wrong when checking potentially unreliable systems or equipment, how likely failures or malfunctions are to occur and how severe the consequences can be? Are you sufficiently equipped to cope with any failures or malfunctions that may occur and their consequences?

MCFs can be dangerous. For example, after replacing a tail rotor component a routine level-flight may be requested to check the tail rotor functions. What if the tail rotor fails due to a problem undetected during maintenance? After all, this is the reason why a check flight is performed: to verify that everything is working correctly because that might not be the case. Be prepared to any eventuality and to cope with any emergency promptly and effectively.

Preparedness starts well before the MCF. You should know which maintenance operations were performed to know which systems could fail. You should also plan an adequate flight path and operating area in case of emergencies requiring an immediate landing (e.g. autorotation).

MCF is a multidepartment activity

MCFs aren’t standards flights, they require the involvement of three departments in your organisation: the CAMO, the Maintenance Organisation, and the Operations Team. All have their own internal MCF procedures and responsibilities, but they must communicate and work together to ensure a safe and effective flight.

The difference between Level A or Level B MCFs?

Regulation (EU) 2019/1384, NCO.SPEC.MCF.100 “Levels of maintenance check flights” has introduced a distinction in Regulation (EU) No 965/2012 between Level A and Level B MCFs:

1. “Level A” MCF is 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;
2. “Level B” MCF is any MCF other than a “Level A”.

Operators often wonder which category to use for a given MCF, as any of the systems that need to be checked in the MCF is to be identified as potentially unreliable and the Flight Manual reports abnormal and emergency procedures for most failures.

ESPN-R Maintenance Check Flight Manual and Risk Assessment Guidance

The ESPN-R Team Ops and SMS has developed a Maintenance Check Flight Manual and Risk Assessment Guidelines to assist operators implementing European MCF rules and suggest how to set up and manage an MCF Programme.

The ESPN-R MCF Manual is a comprehensive, ready-to-use manual operators or maintenance organisations can voluntarily adopt and customise. This Manual will help implementing a good MCF organisation and good procedures. It includes a MCF form to be used by the CAMO, Certifying Staff and the MCF pilot guiding them through suitable steps.

The ESPN-R MCF Risk Assessment Guidance suggests how to assess and mitigate MCF risks and helps defining whether an MCF should be classified as Level A or Level B, based on the risk level of possible consequences would the systems to check in flight fail.

These two documents are attached here below. They may be downloaded, used, and adapted free of charge. Safe MCFs!

Operating a Non-Complex Helicopter?

The requirements for non-complex helicopters are defined in NCO.SPEC.MCF. It isn’t required to develop Manuals or a Standard Operating Procedures like for complex helicopters, the main issue is to decide whether a MCF is a Level A or Level B. This decision is however usually easier to make and Level B MCFs are performed as regular NCO flights.

Text suggested for inclusion in CAT OM-A Chapter 8

Here is a text to be used for non-complex helicopters, compliant with NCO.SPEC.MCF. This text is suggested for inclusion in CAT OM-A Chapter 8, chapter 8.7. Non-Commercial Flights under AOC. Consider Integrating this text in you CAT OM-A Chapter 8

8.7.9. MCF

8.7.9.1. General

A Maintenance Check Flights (MCF) is defined as a flight for the purpose of proving the airworthiness of an aircraft or its equipment. These flights are performed after maintenance and are not part of initial airworthiness approval. A maintenance check flight must be conducted with an aircraft that has been released to service with incomplete maintenance.

The flights described only cover non-complex motor powered aircraft and are based on NCO.SPEC.MCF. Complex motor powered aircraft maintenance check flights are covered in a separate SOP under part SPO.

There are two Levels for MCF:

• “Level A” maintenance check flight 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;  
• “Level B” maintenance check flight for any maintenance check flight other than a “Level A” maintenance check flight.

Before each MCF we determine and communicate whether this flight is Level A or B. For each MCF an appropriate checklist is provided and a safety briefing is conducted.

Generally, tested items are considered as inoperative. Before the flight we identify which procedures need to be altered, and the abnormal and emergency procedures for failure of each equipment assumed to fail or become inoperative.

Specific pre-flight briefing topics:

• Aircraft status (e.g. missing items, inoperative Items)
• Summary of maintenance, airworthiness status
• Flight program, specific procedures and limitations allowing to determine complexity of flight
• Steps (e.g. “read and do”) for the in-flight assessment(s) of the systems to be checked.
• Definition of the simulated emergency procedures necessary for the assessment(s)
• Risk mitigation strategies
• Crew members' responsibilities and coordination including task specialists
• Safety briefing for task specialists
• Information to Air Traffic Control (ATC)
• ATC, airspace
• External conditions
• Weather and light conditions
• Terrain
• Airport (runway, equipment) / operating site
• Specific documentation on board
• Result of the maintenance check flight and related data
• Accurate recording of required maintenance actions after the flight
• Post-flight briefing

Additional points are considered for operating checklists:

• Contents of the flight program and procedures
• Limits (not to be exceeded)
• Specific entry-conditions
• Task sharing and call-outs
• Contingency plans according to missing or inoperative items
• In-flight recordings

8.7.9.2. Crew Composition

To ensure that appropriate levels of safety are maintained, maintenance check flights will be conducted by flight crews (FC) who have satisfactory experience. It is necessary that the FC fully understands the significance and intent of the check, as well as techniques used to minimise the risk associated with some tests.

The Pilot In Command (PIC) will identify the need for additional crew members or task specialists, or both, before each intended MCF, taking into consideration the expected FC or task specialist workload and the risk assessment. No other persons are allowed on board a Level A MCF.

The following FC are allowed to act as Commander during MCF:

• Pilot nominated and instructed for these type of flights by the Nominated Person Flight Operations (NPFO).

8.7.9.3. Operating Procedures

Simulated abnormal or emergency procedures in flight A PIC can simulate situations that require the application of abnormal or emergency procedures with a task specialist on board if the simulation is required to meet the intention of the flight and if it has been identified in the check list or in operating procedures.

Systems and equipment checks When a maintenance check flight is intended to check the proper functioning of a system or equipment, that system or equipment must be identified as potentially unreliable and appropriate mitigation measures must be agreed on prior to flight in order to minimize risks to flight safety.

References

Commission Regulation (EU) No 965/2012 | EASA (europa.eu) Air Operations, Annex VII (Part NCO), SUBPART E: SPECIFIC REQUIREMENTS: SECTION 6 – Maintenance check flight (MCFs), and Annex VIII (Part SPO), SUBPART E: SPECIFIC REQUIREMENTS: SECTION 5 – Maintenance check flight (MCFs).

Also available in eRules format: Easy Access Rules for Air Operations | EASA (europa.eu).

Commission Implementing Regulation (EU) 2019/1384 | EASA (europa.eu) has amended Regulation (EU) No 965/2012 Air Operations among other as regards the establishment of operational requirements for the conduct of maintenance check flights. Several provisions were added, including NCO.SPEC.MCF.100 Levels of maintenance check flights in SUBPART E: SPECIFIC REQUIREMENTS: SECTION 6 – Maintenance check flights (MCFs) and SPO.SPEC.MCF.100 Levels of maintenance check flights in Annex VIII (Part SPO), SUBPART E: SPECIFIC REQUIREMENTS: SECTION 5 – Maintenance check flight (MCFs).