Development of Aircraft Operating Manuals
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As is often the case in aviation, different manufacturers, different National Aviation Authority (NAA), or different users often refer to a given item by different names. The naming of aircraft manuals is not an exception. This article uses the terms Aircraft Operating Manual (AOM) and Flight Crew Operating Manual (FCOM). However, each of these designations is interchangeable with other terms. As examples:
- Aircraft Operating Manual: This manual might be referred to as Aircraft Flight Manual, Airplane Flight Manual or Aeroplane Flight Manual (AFM)
- Flight Crew Operating Manual: Also referred to as Aircraft Operating Manual (AOM), Aircraft Operating Instructions (AOI) or, more simply, Pilot's Manual.
Further confusion arises with the introduction of terms such as Operations Manual or Company Operations Manual (COM) which deal with how the organisation conducts flight operations and are a requirement imposed by the NAA.
Aircraft Operating Manuals/Flight Crew Operating Manuals (AOM/FCOM) constitute the primary flight crew reference for the operation of an aircraft under normal, abnormal, and emergency conditions. These publications include system descriptions, normal and emergency procedures, supplementary techniques, and performance data. Along with the initial training course, the AOM/FCOM constitutes a trainee's first introduction to their new aircraft. This is normally followed by fixed-based or full-flight simulator training and, ultimately, operating the actual aircraft. Operating manuals must meet the needs of initial training, transition training, and line operations.
The contents and presentation of operating manuals must meet the respective needs of different users (e.g. trainees, line pilots transitioning to a new aircraft, instructors, and check airmen). The background and profile of these users differ in terms of technical/academic background, flying experience, and experience in previous types of aircraft.
Learning is a "linear process" that includes studying and understanding basic systems, normal procedures, abnormal/emergency procedures and, ultimately, specific operational aspects. In contrast, flying is a "contextual process" where the need for information results from a contextual interrogation (e.g. what do I need to know to achieve my goal in the prevailing context ?). Operating manuals must therefore mirror the users mental model in terms of goals - what to do, when, how, which option to choose to best achieve the goal. The contents of operating manuals must consequently be goal and context oriented. They must describe the operation of systems and the use of various controls in the operational context where they will be used, going from the mission to the goal, from the goal to the procedure, and from the procedure to the task.
Authoring operating manuals requires considering all aspects of the users, including their profile, mental model, expectations, and behaviour. In other words, this implies defining what the reader needs, the way the reader needs it, and where the reader expects to find it in the publication. The analysis of in-service occurrences sometimes challenge these operating assumptions and leads to integrating corresponding lessons learned into operating manuals and training.
Although often authored by non-airline-pilots and non-native-English speakers, AOM's / FCOM's must be written for pilots, from a pilot's perspective, and in pilot's terms/words. Authors of these publications must be aware that the value of information is driven by its contribution to acquiring knowledge and understanding for using the aircraft toward a given purpose (e.g. use of automation for the conduct of a non-precision approach). As modern aircraft are complex - reflecting the complexity of today’s operating environment - the challenge of the operating manuals is to present this complexity in simple terms and supporting illustrations. As a consequence, the description of systems and the description of procedures should establish bridges between systems descriptions and procedures:
- How is the system designed?
- Why is the system designed this way?
- How does the system interface and communicate with the pilots?
- How to operate the system in normal and non-normal situations (preparing the pilots for the recognition of failures and for the identification of the applicable procedure) ?
Most importantly, operating manuals should not leave the reader with any questions. Sentences should be concise and specific, alternate options and their use should be precise and not left to interpretation. Discussing the level of information to be provided in operating manuals (balancing the need-to-know and the nice-to know) has been a debate for decades. It is a technical debate sometimes biased by legal considerations. The publications should adopt the concept of operational-need-to-know. At each operator's level, this concept must be agreed upon by all involved parties to include operations engineering, flight operations, fleet management, training department. The operational-need-to-know can be defined as whatever information is necessary or useful to the flight crew to operate (i.e. fly, navigate, communicate and manage) the aircraft in any normal, abnormal or emergency condition, for :
- applying published procedures
- exercising airmanship and standard practices (best practices)
- exercising informed decision-making
In addition to its contents, a well-thought and laid out operational documentation ergonomics offer the following advantages for the reader:
- Reduced reading time (easier and faster access to information)
- Reduced risks of interpretation errors (enhanced understanding)
- Faster learning (better information capture and retention)
Paper vs Electronic Operating manuals
Specific considerations should be made regarding paper documentation vs electronic documentation.
Accessing paper documentation is based on a two-steps process:
- What to find? ( identification of context and need for information )
- Where to find? ( knowledge of the AOM/FCOM structure and contents )
An electronic documentation may just mirror the traditional paper documentation and offer a mere "book-like consultation". However, if so designed, it may offer a powerful "scenario-based consultation", whereby all elements of information have been contextualized (type of information, prevailing condition and context) and are presented to the crew automatically (e.g. when system schematics reflecting the prevailing context. For example, hydraulic system low pressure or procedure(s) applicable for prevailing predicament or performance data impact (if any) on prevailing condition
The operational documentation for publications such as the AOM / FCOM should be:
- Pilot oriented
- Easy and practical to access and use
- Easy to understand
- Accurate and dependable
- Self-contained and self-sufficient
- Stable (avoiding too frequent changes, unless they are considered critical)
Probably more than any other aspect, the operating manuals must be "trusted" as they constitute the primary reference in case of contingency.
- ICAO Annex 6: Operation of Aircraft, Appendix 2 - Contents of an Operations Manual;
- ICAO Doc 9376: Preparation of an Operations Manual;