Starting the implementation or revision of an Aircraft Maintenance Program (a fixed or rotary wing) is a responsibility that must be assumed as such. This action will give control to scheduled, unscheduled, and recommended maintenance that must be performed on an aircraft. We know that several figures will later review this program as QC of the operator and/or the local DGAC. Still, we must ensure that it complies with the minimum established by the manufacturer, design, and local authority before this approval.

In addition, it is essential to consider that since 2013 with the publication of ICAO Annex 19, the aviation industry has framed Operational Safety as its primary staff, and the correct control of a maintenance program in the aircraft plays an essential role in this issue. To implement an accurate aircraft maintenance program control, there is a lot we need to know; however, in this post, we will start based on my experience with what Soma considers essential, i.e., the starting point, and we will detail it with the answer to 3 questions:

• What is the manufacturer’s manual or document that will give me the guidelines for controlling my aircraft?

Suppose we must know that every aircraft has a maintenance manual (AMM – Aircraft Maintenance Manual), and we must also understand that this is not the only manual of an airplane. In that case, there is a list that we will know from accessing the technical publications for the fleet. It is there where the navigation begins to make a correct Maintenance Program. It is also necessary to consider that manufacturers usually structure their maintenance manuals always under the same philosophy, regardless of the model of the aircraft you are working on. By this, we mean that if someone is responsible for a maintenance program for a Boeing 737-800 and we are already familiar with this program, We can also work with a B767 or a B747 taking into account that it is the same manufacturer and this usually structure their rules always under the same philosophies. For example:

Boeing usually uses the MPD (Maintenance Planning Document) under the Volumes structure to segregate the instructions for the different controls.

Similarly, Airbus (for fixed-wing) gives its maintenance program instructions under an MPD. Usually, its structures are in sections such as systems, zonal, structural, and airworthiness limitations. Immersed in these sections, it usually gives instructions for controlling the aircraft components under their different categories.

Bombardier, for example, also has a manual dedicated to maintenance planning called MPM (Maintenance Planning Manual), divided into different sections to structure its maintenance instructions.

Suppose we will work with smaller aircraft such as Cessnas or a Diamond. In that case, we should know that this manufacturer uses the Aircraft Maintenance Manual AMM or Service Manual (SM – Service Manual) to give maintenance instructions and will always point to Chapters or Sections 04, 05, and 12 for AMM and Section 2 (it is the most common) for the SM.

This same philosophy can be seen with Bell aircraft (a rotary wing), where the manufacturer typically takes us to Chapters 04, 05, and 12 of their MM.

Defining precisely how each manufacturer will work is impossible. We must also consider more documents that we could be failing to consider, which is also crucial for the proper control of an aircraft. Still, even so, we know the manufacturers and navigate better in their manuals if we get used to their philosophies. The important thing is to have good analytical skills to make the crosses that the manual details us. We usually make mention of separate documentation from the manual where we are extracting the information to build our maintenance program. Another critical point is always to have access to their technical publications and ensure that we have the latest revision. Without updated technical design publications, we will not be complying with a correct maintenance program control from what we call the starting point.

• What should I know before taking responsibility for a Maintenance Program analysis?

Four simple factors before taking responsibility:

1- The first thing to know is that there are rules that make us the way; the FAA, EASA, ICAO, and DGAC Local play a key role. They are responsible for designing for operators the structure to be met in a maintenance program or detailing the minimum items to be completed. Then our main checklist will be the regulations of these entities, depending on the aircraft we are operating and the areas in which the flight line of the plane will be maintained.

2 – We have already identified the manual to use. Another point to know whether or not we have experience in a maintenance program analysis is that the manufacturer will give us the instructions of scheduled and unscheduled services to be performed, which are usually called Service Check. Also, regardless of the aircraft model, we must look for instructions for Airworthiness limitations, Aircraft Component Control (Life Limit, Component Inspection, Time Limits Components, etc.), and structural inspections, which are usually labeled as Structural Inspection, Corrosion Program, among others. It is also imperative to know the different control categories for a component, be it Hard Time (HT), Life Limit Part (LLP), Condition Monitoring (CM), or On Condition (OC), and to know what we are controlling, i.e., if it is a Class 1 component then we see that it will have a series of inspections dedicated to its systems and sub assy components such as LLP and HT. The organization of the structure of the maintenance program to be performed will be the template to achieve a correct control, we could structure it in sections, volumes, or chapters, but ideally, the important thing is to separate the different types of rules by category, i.e., separate for example airframe inspections to component inspections, also have independent what refers to structural inspection items and unscheduled inspections. SOMA suggests that the engine inspection program is entirely separate and includes in that section its normal controls, listing bulletins, LLP, QEC, etc.

3 – We must also consider for the correct interpretation of a maintenance program that the items listed in the manufacturer’s program usually indicate whether or not they apply to the aircraft to be controlled, i.e., its effectiveness number, model, series, configuration, among others, are essential items. We must know them for each of the aircraft we intend to control.

4 – It seems obvious, but it is necessary to know the definition of Flight Hours, Cycles, Landings, and other types of controls such as calendar times, RIN, External Load Time, External Load Event, NG Cycles, NF or NTL Cycles, Engine Start, Operating Hours, among others, which will always be detailed by the manufacturer in the manual or maintenance program document so that we know how to keep track of these items and project correctly the following scheduled maintenance compliance.

• In addition to the control items detailed in the manufacturer’s maintenance planning manual, what other controls should I consider?

There is a defined series of controls for aircraft but we can not detail my tips for analysis and management of each of them in this post. Still, of course, eventually, SOMA Team will share my experience in the following weekly publications; however, as we said before, the manufacturer’s manual usually gives us the crossing to the following documents necessary to have a correct MP, and we must pay attention of course to the local authority regulations and design.

Since we are at this point, to not extend the post, we could start a small list and give an overview of the universe we must know to have our aircraft correctly controlled.

• Airworthiness Directives (AD) is the rule of Aeronautical Authority Design and local. Therefore, we must control the AD of each aeronautical product under our responsibility.
• Service Bulletins are mandatory or recommended items defined by the manufacturer of the aeronautical product, which we must have listed and controlled.
• STC (Supplemental Type Certificate) is the mandatory or recommended modifications made to the aircraft that could affect even its configuration. These must be listed and controlled along with the ICA, the Airworthiness instructions to control such STC.
• Dent, Buckle, or Repair, basically every hit or repair that the aircraft has must be registered in a Structural Mapping, and, commonly, this is supported under the Repair Manual of the aircraft since each one of them must be monitored in time, even when we talk about a Definitive Repair.
• OCCM, or a list of components installed in the aircraft that have no maintenance limit, but a correct control of these components could help us develop a very mature reliability program for the organization.
• More documents indicate scheduled maintenance instructions such as the CMR, ALI, and SFAR88, which vary depending on the size or model of the aircraft. Still, their correct interpretation and control are mandatory.