Explainer
The Maintenance Planning Document (MPD)
The Definition
The Manufacturer's Scheduled Maintenance Baseline
An aircraft needs two kinds of maintenance data. One kind says how to do a job: the procedures in the aircraft maintenance manual. The other says which jobs to do and when. For a transport aircraft, that second kind arrives as the maintenance planning document: every scheduled task, its interval, and the aircraft it applies to, laid out so planners can group tasks into checks.
Regulators treat the MPD as a recognized starting point. EASA's acceptable means of compliance for maintenance programs has long said a program should normally be based upon the maintenance review board report where applicable, the maintenance planning document, the relevant chapters of the maintenance manual, or other maintenance data containing scheduling information.
Where It Comes From
What the MPD Is Derived From
“The maintenance planning document is derived from” is one of the most searched completions of the phrase, and the answer is a chain of four documents:
- MSG-3 analysis
- The analysis method, published by Airlines for America (formerly the Air Transport Association) and recognized by the FAA, Transport Canada, and EASA. It is based on reliability-centered maintenance and works through systems and powerplant, structures, and zonal items, including lightning and HIRF protection.
- The Maintenance Review Board Report (MRBR)
- The result of applying MSG-3 to a new type through working groups and an Industry Steering Committee. The report is produced and owned by the manufacturer, accepted by the steering committee, and approved by the FAA's Maintenance Review Board. It holds the minimum initial scheduled maintenance requirements.
- The Maintenance Planning Document (MPD)
- The manufacturer's planning document that operators work from. It contains the MRB tasks as well as the airworthiness limitations, arranged so a planner can build checks from them.
- The operator's maintenance program
- Each operator's own program, built on the MRBR or MPD, adjusted for its fleet and operation, and approved by its own authority. This, not the MPD, is what the aircraft is actually maintained to.
The MPD carries one category of task that MSG-3 did not produce. The airworthiness limitations come from certification: structural fatigue and damage tolerance analysis, fuel tank safety, and the system safety assessments behind certification maintenance requirements. The FAA's guidance on maintenance review boards notes that some candidate certification maintenance requirements become CMRs listed in the Airworthiness Limitations section, while others are met by an equivalent MRB task, and that those MRB tasks cannot then be deleted from an operator's program.
Both kinds sit side by side in an MPD, but they are not equal. MRB tasks are a minimum baseline that an operator can adjust with evidence. Limitation items cannot be changed without the approval of the authority behind them.
In Practice
From MPD to Maintenance Program
Nobody maintains an aircraft directly to the MPD. Each operator builds its own maintenance program from the MRB report or MPD and submits it to its own authority, which approves it or, in the US, authorizes it through operations specifications. A national authority's checklist for approving such a program describes the MPD as one of the best sources of information, containing MRB tasks as well as airworthiness limitations, and then lists what the operator has to add or reconcile:
- Airworthiness directives
- Repetitive ADs that the manufacturer has not already folded into its data.
- Modification status
- Modifications and service bulletins embodied on each aircraft, which can change the tasks that apply to a particular serial number.
- Repairs
- Some structural repairs bring supplemental inspection requirements of their own.
- Utilization and environment
- Hours and cycles flown per year, and the conditions the fleet operates in, which shape how tasks are packaged into checks.
- Reliability data
- Evidence from the operator's own reliability program, the basis for adjusting intervals over time.
The MRB report is revised as service experience accumulates, the MPD follows it, and the operator's program has to track those revisions too. That is the same currency problem every maintenance document has, covered in our piece on keeping service bulletins and revisions current. For what a US air carrier maintenance program contains, who authorizes it, and where task cards fit, see our guide to the aircraft maintenance program.
An Example
What a Planner Reads
Formats differ between manufacturers, and we do not reproduce any of them here. Whatever the layout, a planner needs each entry to answer four questions. What is the task, and which manual procedure performs it. Which aircraft does it apply to, by model, configuration, or modification status. How often, in flight hours, flight cycles, calendar time, or a combination. And where it came from: an MRB task, a certification maintenance requirement, or an airworthiness limitation, because that origin decides whether the operator may ever change it.
The first question is why the MPD and the maintenance manual have to agree. When a task points to a procedure and either document is revised without the other, planners end up scheduling a task whose procedure has moved or changed.
Smaller Aircraft
When There Is No MPD
MPDs are typical of transport aircraft that went through a full Maintenance Review Board. The FAA describes a Maintenance Type Board as the usual choice for smaller or less complex aircraft, and some types have only the manufacturer's recommended maintenance procedures. Where there is no MRB report or MPD, the scheduling data lives in the maintenance manual itself: chapters 04 (airworthiness limitations), 05 (time limits and maintenance checks), and 12 (servicing) in the ATA iSpec 2200 numbering.
For a holder of a design approval, scheduling information is part of the Instructions for Continued Airworthiness whether it is published as an MPD or as a chapter. For where these documents sit among the others an aircraft carries, see our guide to the types of aircraft manuals, and for why copies are controlled, our guide to obtaining OEM manuals.
FAQ
Questions We Hear
What is a maintenance planning document?
A maintenance planning document (MPD) is the aircraft manufacturer's document listing the scheduled maintenance tasks and intervals for a type, from which operators build their own maintenance programs. It contains the tasks from the Maintenance Review Board Report as well as the airworthiness limitations, so a planner has the manufacturer's whole scheduled maintenance baseline in one place.
What is the MPD derived from?
Mainly from the Maintenance Review Board Report (MRBR), which is itself the output of MSG-3 analysis carried out by the manufacturer, operators, and regulators for a new type. The MPD also carries the airworthiness limitations, which come from certification rather than MSG-3: structural fatigue and damage tolerance analysis, fuel tank safety, and the system safety assessments that produce certification maintenance requirements.
What is the difference between the MRBR and the MPD?
The MRBR is the approved report of minimum initial scheduled maintenance requirements from the MSG-3 process. The MPD is the manufacturer's planning document that presents those tasks, together with the airworthiness limitations, in a form operators use to build checks and programs. Regulators recognize both as a starting point for an operator's maintenance program.
Is the MPD the approved maintenance program?
No. The MPD is the manufacturer's recommendation and baseline. Each operator builds its own maintenance program from the MRBR or MPD and submits it to its own authority, which approves it or, for US air carriers, authorizes it through operations specifications. The airworthiness limitations and certification maintenance requirements carried through from the MPD remain mandatory inside that program.
Does every aircraft have an MPD?
No. MPDs are typical of transport aircraft that went through a Maintenance Review Board. Smaller or less complex aircraft may go through a Maintenance Type Board instead, or have only the manufacturer's recommended maintenance procedures. Where there is no MRB report or MPD, the maintenance manual's chapters on airworthiness limitations (04), time limits and maintenance checks (05), and servicing (12) provide the scheduling data.
Where can I get the MPD for a Boeing or Airbus aircraft?
From the manufacturer, under the technical data agreement that comes with operating or maintaining the type. MPDs are licensed manufacturer data, so copies found on file-sharing sites are neither authorized nor reliably current. Our guide to obtaining OEM manuals explains the legitimate routes.
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Keeping the MPD and the AMM in Step?
We structure scheduled maintenance data so every task links to its procedure, its applicability, and its source, and so a revision to one document cannot quietly break the other.