Exercise MERLIN VORTEX is the pre-deployment environmental training for the Merlin Force. It is a four month rolling detachment to El Centro, California, designed to give helicopter crews, engineers and support staff experience of working in a 'hot and high' environment prior to their deployment to Afghanistan in the Support Helicopter role in late 2009.

The Exercise started in late August 2009 and by the end of November 2009 it is expected that all 5 flights of 28 (Army Co-operation) and 78 Squadrons will have completed the necessary training in El Centro to enable them to be familiar with the environmental aspects of operations in Afghanistan. This is not only acclimatising themselves for working in such extreme conditions, but also the helicopters.

All aircraft perform differently in different environmental conditions and military aircraft are no exception. It is essential that both the aircrews and the engineers have experience of working with the Merlin in extreme temperatures at high altitude, and in dusty conditions, prior to deployment to Afghanistan. Being armed with this experience will enable the RAF Benson personnel to concentrate on the operational tasks that they could be presented with. It will also ensure that what is called the 'bedding in' process - where the Merlin joins the other coalition helicopters in theatre - is as swift and smooth as possible.

As well as operating the aircraft in the environment, Exercise MERLIN VORTEX will also enable the aircrew to gain essential experience in operating the aircraft with the new modifications. These modifications include the use of Display Night Vision Goggles (DNVGs), which have previously only been used by the Puma Force in Iraq. DNVGs will enable the Merlin crews to perform more effectively in a high-tempo environment such as an operational theatre when compared to standard Night Vision Goggles (NVGs).

NVGs simply allow the individual to use residual light to 'see in the dark' - effectively they use the residual light to highlight features such as terrain and buildings. This presents the crews with the classic 'green' view of the world around them. DNVGs still use residual light and still provide the 'green' view of the world but they also come with a display feature, which effectively transfers some of the key aspects of the flight instruments in the cockpit to the lens of the goggles. This reduces the need for the pilot to perform visual instrument checks as the information that is available on the instruments will be readily available in his field of vision. But they require training to operate effectively.

Imagine driving a car and looking down to check aspects of your car and journey such as your speedometer, your fuel level, your engine temperature, or your satellite navigation system. Now imagine that information readily available on your windscreen. Whilst this may make driving the car easier by resulting in less physical movement (which in extreme conditions such as those faced in Afghanistan can be physically wearing), it also disrupts your field of vision. Your brain now has to process steering, changing gear, braking, applying the clutch, checking the mirrors, navigating, and turning on indicators and lights, and at the same time it has to process your speed, your location, your fuel level and your engine temperature. Whilst you are adept at doing this naturally with a turn of the head, having that information in your field of vision can be distracting and it can take a short while for your brain to 'learn' to look at what it needs to look at when it needs to look at it. The same is true of flying a helicopter wearing DNVGs.