Spare Parts Supply for Airline Operators and Power-By-the-Hour Programs are changing the spare parts aviation industry; recent developments in civil and military aviation have indeed changed (and are changing) the industry substantially. Today MROs (Maintenance Repair and Overhaul Organizations) as well as the OEMs (Original Equipment Manufacturers in the sense of aircraft manufacturer) provide spare parts to their airline operators with so-called PBH (power-by-the-hour) programs (also called for example maintenance-by-the-hour programs), with a certain guaranteed (or agreed upon) service level.
The logistics necessary to support such complex network has reached a high level of complexity whereby component exchange programs are proposed to multiple operators, sometimes not only at the main base but also to secondary bases (or outstations). Initial Provisioning Recommendations calculated with standard and old- (or out-) dated procedures, where for example spare parts are distributed among stations according to weights based on the past history of failures at the stations or based on a certain statistical protection level, are no longer sufficient and new simulation and optimization procedures are now necessary. And not just that. Spare parts management in aviation need to think about new way to reduce the level of inventory as much as possible, with arrangements between airlines operating the same type of aircraft at the same base or airport.
The underlying idea here is to:
- share aircraft parts
- share aircraft tooling
- share ground handling equipment and manpower
- share minimal technical facilities such as line maintenance facilities
The objective is thus to to generate economical savings through the pooling or sharing of resources while establishing cost sharing formalities. Pooling (“The Pool”) is not a new concept and is indeed common across to several industries as it linked to resource management and to the grouping together of resources (equipment, assets, facilities, personnel, …) for the purposes of maximizing advantage and/or minimizing risk to the user(s), in this case, the airlines.
Reduce airlines operational delays and cancellation by sharing resources and technical support at line stations throughout the world is essential as well as generating economic savings by minimizing investments otherwise required. However, this is just one face of the challenge. Whenever a part or component (also called LRU or Line Replacement Unit) on an aircraft becomes defective, it has to be removed and replaced by another component taken from the airline on-site stock (provided such part is immediately available). The part removed must then be sent off to a maintenance shop to be repaired, and the aircraft will remain on ground and the passengers will be delayed until a replacement unit from the maintenance shop or from a neighboring base is provided (unless such spare is immediately available from the on-site spare stock, but even in this case, although the aircraft will not be delayed a replenishment of the stock has to be carried out).
In any case, a LRU (which can be a small electronic component or a whole engine) is essential and the spare inventory that has to be placed at line repair stations has to be carefully evaluated in order to (i) decrease time delays due to unanticipated failures, and (ii) be able to quickly replenish secondary bases during the time their parts are being
repaired (in aviation this is called TAT or Turn Around Time, and can vary from considerably depending on several factors).
How many spares should be kept and where?
What is the risk associated with positioning (or not) any such spares at a particular location?
The questions above are not easily answered, more so since the number of spare parts on an aircraft is not small and most of the times seeking an exact optimal solution is not possible (too time consuming, for example) and approximate (heuristic) algorithms need to be used. In addition, as a further challenge, a particular LRU may be required by several stations that can only be replenished by one central warehouse (no supply from one secondary base to the other, that is, in real life terms no flights or reasonably quick direct means of transportation from one secondary base to the other).
New computational models geared towards simulation-based optimization for the aviation components exchange business are being developed as well as new ways to facilitate the exchange of ideas and cooperation are being proposed. These ideas and concepts are going to be applicable (and of great value and advantage) not only to airlines but also to helicopter operators, military aviation as well as general aviation, and change the industry for the better.