The British Antarctic Survey Operates Allison-Equipped Vehicles
Eilidh Forster, Allison
Transmission Europe B.V.
Choosing the right equipment is critical in the drive for productivity - a truck has to work efficiently and keep on working. However, in this unique case the performance and reliability of equipment could also be critical to operator and passenger survival in the potentially dangerous extreme weather situations that threaten Antarctic operations.
Overcoming some of the most extreme operating conditions on Earth, Allison fully automatic transmissions have been helping provide logistics support to the British Antarctic Survey, in Antarctica, for 30 years. Often working in treacherous conditions with unimaginable temperatures and thick snow, performance and reliability of the support vehicles is essential for human survival on this frozen continent.
Antarctica, the ice desert
World-class scientific research
There are various off the shelf and specialised vehicles at Rothera and Halley Antarctic stations. At Halley, the vehicles are all tracked, giving all year round access around the Brunt ice shelf, whilst at Rothera there is a mix of wheeled and tracked vehicles to deal with the ever changing summer conditions as the snow recedes leaving bare rock around the base location. All the heavy plant vehicles are powered by diesel engines which require special pre-heating before they are started in low temperatures, and they also use alternative fuels such as JET A1 aviation fuel to stop the waxing of regular diesel fuels. All the vehicles are fitted with automatic transmissions to ensure they are simple to operate and be less prone to damage.
Tucker Sno-cats are used extensively for transporting personnel and towing sledges of up to 8 t weight, containing loads such as supply deliveries from BAS's main logistics support ship, RRSErnest Shackleton. Powered by Detroit Diesel or Cummins engines of about 170 HP and driving through Allison automatic transmissions to four tracks, the Sno-cats are steered by turntables fitted to the axles.
BAS currently run a fleet of 12 Tucker Sno-Cats. BAS's technology and engineering division is responsible for managing all aspects of BAS vehicles in Antarctica, with vehicle managers often spending the winter operating season at Rothera or Halley. Deputy project manager for logistics for the Halley VI build project, Martin Bell, formerly the vehicle manager responsible for vehicle purchasing and maintenance, has spent a total of 9 years in Antarctica on various contracts. With his experience as vehicle manager for BAS, Mr. Bell understands better than anyone the challenges of operating a fleet in harsh environments and it does not come much harsher than Antarctica.
"Day to day planning and preparations for Antarctic operations and operating in harsh conditions are a constant challenge," says Martin Bell. "Low temperatures, deep snow, wind, traction, steep gradients, ice and long operating hours create difficult operating conditions and the pressure to maintain vehicle reliability is huge."
With limited maintenance facilities in Antarctica and the nearest workshop thousands of miles away it is essential that maintenance requirements are kept to a minimum. "We run AT545, MT643 and MD3560 Allison transmissions," says Martin Bell. "No special design modifications are made to the transmissions for coping in the Antarctic environment and very little maintenance is required, only oil and filter changes every 500 operational hours. Though a small oil heater is installed in the vehicles, this is often not used," he adds.
If a vehicle does break down, depending on the problem it is either fixed on site, returned to the stations garage for repair or sent back to the UK. "It is very rare that we cannot fix things on site but if a serious problem occurred we would have to send the vehicle back to the UK to our workshops in Cambridge or back to the supplier," adds Martin Bell.
Losing vital vehicles would present serious problems and increase daily operating challenges even further so it is essential that vehicle productivity is kept high.
With prevention preferred over failure, Allison has over 50 years of experience of producing automatic transmissions, ensuring their gearboxes are durable, whatever the terrain. The Sno-Cat is equipped with an Allison six-speed transmission, with ratios carefully selected to maximize its performance in the challenging snowy terrain. By reducing wear and tear on the drivetrain, vehicle life is greatly extended and maintenance costs are dramatically reduced. The typical operating life of BAS vehicles is 15 to 20 years. With finite funding and budgets, any money saved in logistics support for BAS activities in Antarctica can be used in funding other functions, contributing to the overall success of research programs.
All Allison gearboxes incorporate a torque converter that makes the best use of the engine power, multiplying torque by a factor of two, making steep, icy gradients easier to climb. It also offers lock up on first gear, which provides direct drive from the engine, reducing heat build up and contributing to drivetrain longevity. Integrated diagnostics in the transmission monitor and provide advance warning of possible transmission related issues. This information reduces the risk of transmission failure, preventing the potentially dangerous situations that could occur on-site as a result. And even if a problem does occur, Allison has incorporated a "limp-home" mode. Crucially, this allows a vehicle to be moved to a position where a technician can safely work on fixing the problem.
The transmissions are worked very hard, often for long operating hours and, coupled with extreme gradients and poor weather, the benefits of Allison's ability to provide uninterrupted power through the shifts is very apparent. The Allison controller also protects the engine and drivetrain from unnecessary damage by prohibiting mis-selection of gears. The torque converter and planetary gearing also increase traction, improving performance and control of vehicles operating on soft snow or loose rubble, conditions which can develop in certain areas as snow thaws in the summer months.
Everyone in the driver's seat
"We have a very comprehensive training period in the UK in September and then on site in Antarctica but quite a lot of our drivers are made up from general staff who have never driven an automatic transmission before. The transmission is easy to use and they like the simplicity," says Mr. Bell.
In very difficult driving conditions such as poor visibility, storm-force winds and uneven ground, vehicle control can be very difficult for even the most experienced drivers. However, with the Allison transmission, drivers are able to stay focused on the route ahead and keep both hands on the steering wheel, allowing much safer, easier operation. Medical testing has proven that drivers of Allison-equipped vehicles enjoy lower stress levels than those driving manuals, which is particularly important when working in a heightened stress environment such as Antarctica.
The Allison transmission also incorporates Adaptive Controls: The gearbox learns drivers' behaviour and adjusts shifting to suit. The Adaptive Controls will retain this optimum shift point over the vehicle life. The sum benefit of this is to protect the driveline and keep the truck working but with excellent drivability, not only is the maintenance team happy, the drivers like using the transmission too.
Furthermore, personnel employment and training are important to BAS so reducing the driving skills required has the welcomed effect of both simplifying and reducing delivery time of necessary training.
Allison will continue to play an important part in the future of BAS operations in Antarctica, with Allison equipped Canadian Foremost mobile cranes being used in the ongoing development (not expansion) of the Rothera site. By replacing old structures and making best use of new technologies, such as improved insulation and energy production and management systems, BAS will further reduce the environmental footprint of the station.
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