The Warwickshire and Northamptonshire Air Ambulance service is using customised Tait mobile radios with the flexibility to be integrated into its aircraft audio system. Read this case study published in the January issue of the Bapco Journal.

Today's market for two way radio installations is dominated by the needs of businesses and service organisations to manage large workforces operating throughout a wide area, or within a site or installation. These include taxi firms and local council maintenance departments, or shopping centres, depots and factories.

Radio equipment suppliers can therefore service the vast majority of customers by offering more or less commodity products, focused on these applications. But when the requirements are a little different, system integrators need more flexibility than is typically on offer.

As chief pilot for the Warwickshire and Northamptonshire Air Ambulance Service Neil Parkinson needed an aviation-approved radio for ambulance channels, capable of being integrated with the Bendix King avionics fitment installed in the aircraft: an Agusta 109 helicopter.

It sounds straightforward enough; except for two critical challenges. Firstly, there are no aviation-approved radios for ambulance channels available off the shelf. And secondly, few two-way radio platforms these days offer the necessary flexibility to allow easy integration into a separate network such as an aircraft audio system.

Meeting the requirements

Tait Electronics is one of the few manufacturers whose products can accommodate the level of customisation necessary to meet low-volume or specialist requirements such as those of the air ambulance service.

The TM8000 series radio sets, as well as the T2000 series selected by system integrator Eddie Jones of Cambridge Mobile Communications Ltd (CMC), are designed to be integrator-friendly. Several internal "options boards" are available for each platform, including the T2000 data interface board selected by Jones to bring the signals he needed to the back of the radio set.

Other options boards include a line interface for integration with a PSTN, and a public address interface. On some models an optional MAP27 data port is also available for connection to modems, printers, data terminals and displays.

On-board integration

The data interface board made integration with the communications system on-board Neil Parkinson's air ambulance quite straightforward. "The board brings all valuable signals to the back of the radio, which makes it easy to connect into almost any system," confirms CMC's Jones. "All the integrator then has to contribute is knowledge: what to do with those signals."

With the system-level interfaces well catered for, setting audio levels was probably the biggest remaining issue facing the integration project. "This was actually a very fine balance, given the acoustic noise generated by the aircraft," explains Jones.

"Also, T2000 radios are usually used with a hand-mike, but in this case we had to modify it to provide audible side-tone so that operators can hear their own voice when wearing headphones. The T2000-series lends itself well to being modified in this way, to meet custom requirements."

Gaining aviation approval for the equipment was also quite easy. Normally, the Civil Aviation Authority (CAA) prohibits such installations, but there is an exception for air ambulances.

At the ground-based part of the system, integrating the air ambulance radio with the central office communications was also relatively easy. The existing radio communications infrastructure of the Two Shires Medical Authority, within whose jurisdiction the air ambulance operates, is built around a Tait base station with Tait portable radios for its staff and installed in road-going ambulances.

"Since we work with two medical authorities, and each of these have their own set of emergency channels, we had to be sure the equipment on board the helicopter was capable of connecting us to either authority," adds Parkinson.

Features for emergencies

Use of the radio during an emergency relies on a handful of basic features. Chief pilot Parkinson explains that from receiving the emergency alert - via 'batphone' from the local medical authority - to being airborne can take as little as 40 seconds.

"From first receipt of the call until we reach the location of the emergency, we are making decisions on the move," continues Parkinson. "As soon as we are in the air, we open communications with the local medical centre. As well as the obvious voice communications modes, we also use data services such as Selcall Status extensively to provide concise and unambiguous updates of our actions, latest destination, ETAs and other information valuable to those controlling the situation and waiting to receive us."

Depending on the location of the emergency, the air ambulance will use any of the 10 hospitals that service the Warwickshire and Northamptonshire region. The air ambulance service covers just over 2000 square miles of Warwickshire and Northamptonshire, with a population of 1.1 million. It costs around $1 million each year to operate, and will typically respond to some 150 emergency calls each year. Around 50% of these are road traffic accidents.

"Any time an occupant is trapped in a car, for example, Police procedure is to call the air ambulance," explains Parkinson. In addition to RTA duties, the helicopter provides an essential ambulance service to rural communities, where journey times can be long and road access sometimes difficult. Fallen horse riders and cardiac arrest patients are the most common 'customers'. "If someone arrests in a remote farmhouse, for example, we can be on the scene within 8 minutes anywhere in Warwickshire."

Parkinson and his crew can also reach anywhere in Northamptonshire within 12 minutes. Contrast these ETAs with the challenges facing a road-going ambulance in a rural environment, with the distances that can be involved as well as narrow lanes, and it is easy to see how the air ambulance has saved countless lives.

Yet the service receives no funding from the local medical authority budget, and is entirely dependent on charitable donations. For this reason, Tait agreed to supply its radio equipment and technical support free of charge, and CMC also donated its time and expertise: owner and founder Eddie Jones has known Neil Parkinson for many years through his personal association with the aviation industry.

Flexible

"The flexibility of the Tait 2000 series platform was fundamental to achieving a workable solution," adds Jones, whose firm specialises in supplying and supporting two-way professional radio. Typical customers include - naturally - taxi firms, local authorities, and retail or industrial sites. "That integrator-friendliness also made this unusual project interesting and rewarding."

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