Fleets Analyzer contain two sub-modules found within the Aircraft and Aircraft Events modules; 'Trend' & 'Projection'. These both permit reporting for consecutive time periods (month, quarter or year options available) covering both selected historical and/or future periods. So if a trend (or projection) was run using the 'Yearly' option, the data & fleet counts (and any other calculated metrics) would be valid as-at December 31st each year. Likewise, if you plotted a monthly view, the information would represent the position on the last day of each month.
Although Trend and Projection are setup in similar ways, there are subtle differences in the methodology employed within which are noted in the sections below:
The Trend tool formulates the output by simply using only the information contained within the history table of each individual aircraft (a snapshot of some of this historical data structure is available on the History tab of each individual aircraft profile). The following are key points to note, regarding behaviour of the Trend module.
- Future deliveries are inserted into future periods for any aircraft holding a current order book status (e.g On Order, Loi, Option etc) using the forecast Delivery Date recorded against each aircraft and inserting into the corresponding future period.
- aircraft will drop-out of future In-Service status and assigned into Storage status, where a future lease end date is identified and storage remains the default status position at the time of this future event (unless a new lessee is identified in advance and the aircraft can be put into future service).
- aircraft can be Retired in a future period but only in circumstances where an aircraft's history table holds the event 'scheduled to be permanently withdrawn from use'. Only a small % of the fleet currently carry this future event record where we know for certain it will be withdrawn and during a specific time frame.
- only reported aircraft utilisation data will show in the Trend historically. If an aircraft does not contribute updated hours and cycles there will be no data showing in the Total Period Hours or Total Period Cycles fields and associated metrics. New utilisation data will therefore not show for any future period.
- for aircraft currently assigned 'In Service' status and where there are no future history events for the specific aircraft indicating retirement or storage event activity then these will continue to show as In Service for all future Trend periods.
The Projection tool achieves all of the above but the following additions and exceptions should be noted:
- Utilisation data is handled differently to the Trend module for both completed historical and future periods. In the scenario where In Service aircraft are detected with no reported utilisation data during a historical period, an attempt is made to estimate and populate missing data using a multi-step algorithm. For future periods, the information continues to be extrapolated forward on the same basis. For more information on this methodology please see the appropriate sections contained within the Fleets Analyzer User Guide.
- In Service aircraft are automatically retired via the application of Retirement Assumptions which are shown within the labelled button next to Add/Remove Metrics. These rules are applied based on an aircraft reaching specified age, hours and cycles; whatever is projected to occur first. Automated retirements are not applied historically to completed periods and only come into force for the remainder of any current period and for all future periods.
- Base maintenance airframe check events (e.g C-Check) can be forecast using the metrics available for selection under the 'Maintenance Checks' category.
Both Trend and Projection will give identical status fleet counts (e.g In Service, Storage, Retired etc) for any completed historical period.