Operations Research: FEL Planning Aid for Transport Helicopters (FELPATH) – 2000

FEL Planning Aid for Transport Helicopters (FELPATH)

TNO-FEL helicopter studies were performed to support the armed forces during procurement, upgrade and deployment of transport, armed and light utility helicopters. For example, TNO-FEL was closely involved in the procurement of the CH-47D Chinook and AS 532 U2 Cougar Mk2 transport helicopters and the AH-64D Apache attack helicopter. An important project concerning the deployment of the transport helicopters is the development of a decision support system FELPATH (FEL Planning Aid for Transport Helicopters), developed by TNO-FEL around the year 2000.



FELPATH enables the planning cell within the combined Command Post of the Tactical Helicopter Group of the Royal Netherlands Air Force and the 11 Airmobile Brigade of the Royal Netherlands Army to plan their tactical transport helicopter operations. FELPATH includes the planning of routes, planning of air moves and the tasking of the transport helicopter fleet. Within tactical operations with transport helicopters three problem areas are recognised and translated into a number of modules in FELPATH:

  • Variation in performance of the helicopter
    The performance (payload/range and fuel consumption) of the helicopter depends on the environment in which the helicopter has to operate; atmospheric conditions, geographical environment and/or tactical situation (positions of pick-up points and drop-off points, use of refuelling points, threats).
  • Variation in the composition of military units
    During an operation, the composition of military units will vary due to the changing demands and needs of ground commanders as a result of the changing tactical situation. Also, the attrition of these units on the battlefield in time changes the composition. This means that air loading tables have to be adapted regularly.
  • Variation in tasking of the helicopter fleet
    Replanning and rescheduling sorties or complete tasks (air moves) take place continuously during transport helicopter operations. Reasons are variation in the availability of the helicopter fleet and crews, airspace control, weather, changes in priorities, et cetera.

These three problem areas are translated into a number of modules in FELPATH. These modules are:

  • Route planning: In this module routes can be defined, including flying speeds, heights, positions of pick-up points, drop-off points and refuelling points, et cetera. The output is the payload of the helicopter, the fuel, the distance and time required to fly a route or mission.
  • Task definition: In this module, the transport task (air move) is defined, i.e. what load needs to be transported with which type of transport helicopter. Also for each particular task constraints on how to carry the loads with the transport helicopters can be defined.
  • Load planning: This module generates sortie-lists of tasks as defined in the module Task definition. Sortie-lists are generated using an optimisation technique or are created manually by the user. To take into account preferable or allowed helicopter load configurations the user is able to select a predefined list with load configurations. The output provides the user with an air-loading table.
  • Allocating & scheduling: each task has its own constraints on time, type and number of helicopters required. In this module, it is possible to schedule the tasks in time such that constraints on tasks are dealt with. The output provides the user with an air movement table of the operation.
  • Database editor: With a fifth module the databases concerning the helicopters and loads can be defined and adapted.

In each module, relevant reports will be generated to support the user in planning transport helicopter operations. Combination of the outputs describes a transport helicopter operation and is called an Operations Script.