THE TRAINING of maintenance personnel needed to service sophisticated aircraft is no longer a matter of using chalk, a blackboard and a box full of surplus parts. With the rapid, accurate detection, diagnosis and correction of faults becoming increasingly important to the turnaround time of an airliner or military aircraft in the service hangar, effective training of maintainers in a realistic environment is ever a critical requirement.

Traditionally, maintenance training uses real parts, mock-ups and even, when available, whole aircraft. These methods have limitations. For example, it may not be feasible, or safe, to supply equipment with the pressurised air, hydraulic fluid, oil or electrical power required to make it work. Raising and lowering an undercarriage on an elevated aircraft to demonstrate realistic malfunctions is not without its dangers.

In addition, teaching engineers how to start engines using the real aircraft eats into engine cycles, pollutes the atmosphere with noise and emissions and uses fuel.

Environmental factors, and the increasing complexity of systems and the constraints imposed by the availability of equipment, means that conventional training methods are becoming inadequate, inefficient and costly.

For the engineer, technology has brought with it new challenges in problem solving and fault diagnosis. Faults need to be diagnosed quickly and accurately, otherwise operational availability is reduced and costs rise. With traditional training equipment, the instructor has difficulty monitoring the diagnostic actions and subsequent corrective measures taken by more than a small handful of candidates at a time.

The Brighton, UK-based division of US manufacturer ECC Simulation offers an alternative to using "the real thing" in maintenance training. Two weapons-system trainers and two mechanical-systems trainers for the EH Industries (Westland/Agusta) EH101 Merlin helicopter, for example, are being developed in conjunction with Westland and the Royal Navy.

The full-scale Merlin cockpit, cabin and underfloor assemblies are produced to a high standard, in some areas being stronger than the actual aircraft, using rugged steel structures, to withstand the training cycle.

The weapons-systems trainer has its own hydraulic and electrical systems, the undercarriage can be lowered and raised at four different speeds and it can be removed and re-assembled. Many of the line-replaceable components can be removed and replaced for training. Similarly, all weapons can be loaded and unloaded. Unlike practising on the real aircraft, if damaged, the simulator can be repaired quickly and cheaply.

The mechanical-systems trainer consists of a similar structure with real aircraft gearbox, actuators, rotors and a large number of simulated systems and associated cockpit displays. Almost 100 training faults can be injected from an instructor's control station.


Simulator advantages

The advantages of such simulators are numerous. The cost of training is reduced, with the expense of manufacturing and operating simulators being much lower than with real equipment. Several of the trainers produced by ECC are portable, so training can be done locally rather than centrally. Simulated equipment is mostly cheaper and more reliable than real aircraft and other equipment components. Training-workshop overhead expenses tend to be lower - there are savings on resources, fuel and other approved aviation materials. There are no aircraft certification costs, and not every aircraft upgrade modification need be carried over to the simulator, only those affecting maintenance of the systems.

The level of safety is considerably higher, both for the trainees and the equipment. There is good control over the working environment and level of risk. Actual aircraft, weapons and other expensive operational systems are not used and no damage to such equipment occurs.

The monitoring of candidates' individual performance is discrete and enhanced considerably. Efficiency is increased, particularly for the instructor who can deal more effectively with large groups of candidates. Availability and serviceability of training equipment is much better - there are fewer parts, and vulnerable areas which students use frequently can be strengthened to reduce wear and tear. Courses are often shorter. Simulators can be reconfigured quickly for a role change.

All known malfunctions and emergencies can be practised safely and realistically. Secondary and tertiary effects can be included. This also applies if a student misdiagnoses a problem. Actual environments can be simulated, too, and no damage is done to that environment.

Source: Flight International