MRO Management

Looking forward: forecasting fleet maintenance requirements

easyJet aircraft engine

Aerogility, an advanced planning system, is helping easyJet to accurately forecast its future fleet maintenance requirements. Ian Harbison reports.

Aerogility was originally developed for the defence market and is in use by a number of military OEMs to support contracts that require guaranteed levels of equipment availability, with financial penalties if targets are not met.

While military flying hours are significantly less than the airline industry, there can be spikes in demand caused by major exercises or temporary deployments at home or abroad. Equally, maintenance intervals are much shorter than for commercial aircraft and engines.

This means it is important to know if extra work has to be carried out to meet requirements.

Aerogility fleet maintenance system

The key benefit of Aerogility, says Gary Vickers, CEO, is that it combines a number of highly detailed mini-databases (intelligent agents) that are compiled at a departmental level by experts and linked to other information sources such as enterprise resource planning systems, operational systems, Excel, logistics and spares/inventory.

It also uses the Amazon Web Services cloud, so it is accessible to all clients or can be behind a firewall.

These can be used in different combinations to match a particular requirement. In this way, a change in one or more parameters can be selected to generate ‘what if’ analyses. Unlike a spreadsheet, the system produces easily understood visualisations of the projected programme schedule.

The system caught the eye of easyJet, which has been exploring a wide range of new technologies to support its operations and an agreement was signed in 2017, the system becoming operational in November 2017.

Swaran Sidhu, head of fleet technical management, says the first step was to explain the airline’s operating environment – a fleet of just over 300 aircraft with high daily aircraft utilisation rates and short turnaround times.

This quickly racks up flight hours and flight cycles and reduces maintenance intervals, especially as the airline also uses equalised maintenance in 750 flight hour packages, which recur roughly every 90 days.

easyJet continues to take delivery of A320 Family aircraft for both growth and replacement purposes. The airline currently has 119 outstanding deliveries in its order book, consisting of one remaining A320ceo, 89 A320neos and 29 A321neos.

The first A321neo was delivered in July 2018, and all of the airline’s A321neo aircraft is the ACF variant, featuring a modified door layout that allows easyJet to have a layout of 235 seats. By the end of 2021, the airline plans to be operating 359 aircraft.

Aerogility aircraft fleet maintenance programme

Traditionally, says Ruth Martin, maintenance operations planning lead, long-term planning has been carried out using spreadsheets, but it can take a couple of weeks to develop a complex programme, and it is easy to miss a detail that might not be caught until much later. Introducing changes is not easy either, she adds.

With Aerogility, complex programmes can be built and run quickly, giving easy-to-use comparison data, and changes can be processed efficiently. Not only is the visual presentation much easier to understand, but it can also be adapted to give a familiar format.

For the maintenance process, the intelligent agents selected by easyJet include:

  • Asset Agents: representing the fleet and aircraft grouped by utilisation, as well as major components (such as landing gear or engines)
  • Sustainment Agents: representing maintenance facilities and component inventory
  • Decision-maker & Process Agents: representing fleet management, component inventory management, cost accountant, and maintenance prediction and scheduling.

Additionally, Aerogility also interacts with the airline’s AMOS MRO software from Swiss AviationSoftware and the Airbus Skywise predictive maintenance programme (see box story). The airline currently uses AerData’s Engine Maintenance Cost Planning (EFPAC) program, but this is also possible with Aerogility.

Aerogility is being used for medium- and long-term maintenance planning, running simulations of the actual flight schedules to identify when individual aircraft will reach their next maintenance check and for hangar slots for heavy checks. This can identify bottlenecks and schedule clashes.

As new data becomes available that may impact the programme, perhaps a hangar slot becomes unavailable, it can be introduced via one of the intelligent agents and a new schedule can be developed. An added benefit is that the schedule also maximises the number of aircraft flying and of seats available for customers.

An 18-month schedule can be generated in 30 seconds, says Vickers. Once the schedule has been developed, it is possible to use it as the basis for other work programmes where there is no constant flow of work, for which Aerogility is really designed.

For example, says Martin, the airline is involved in a major cabin reconfiguration programme, installing the Space-Flex V2 rear galley at a number of MROs in winter. Working with the overall slot programme, allocation of individual aircraft to the partner MROs can be determined – most of the reconfigurations are carried out separately from heavy checks.

Fleet maintenance of easyjet aircraft

It can also help with short-term problems, perhaps a bad week with AOGs or disrupted operations caused by bad weather, in reallocating slots to alternative aircraft. Once the benefits of Skywise kick in, the predictive fleet maintenance data will become one of the intelligent agents, helping to further refine the forecasts.

The importance of Aerogility to the fleet programme is the optimisation of the retirement dates (where there may be associated maintenance and reconfiguration work on leased aircraft) with the delivery dates of new aircraft, ensuring a smooth transition. The return period is expected to be reduced by a week.

Aerogility has been fully integrated with the airline’s landing gear overhaul programme and is generating significant savings through optimisation of removals with winter aircraft maintenance checks. In particular, it has been possible to reduce early removals caused by over-cautious margins, leading to extended time on the wing.

Sidhu concludes that one of the most important aspects of the new software is the cost visibility it provides for the current and future state of the long-term plan, previously hidden or not fully accounted for.

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