Hello Rupert:
I am the person responsible for the design and specification of the instrument panel on the new Series 400 Twin Otter. By profession, I am both an engineer and a pilot, and I have flown in Africa for most of my career. I’ve worked in all the fun places – Angola, Loki, Hassi Messaoud, Liberia, Somalia, the lot of them, and I’ve flown legacy (Series 300) Twin Otters all over the globe.
I’m going to try and address your concerns and questions as best I can, but please appreciate that because we (Viking) have not yet formally announced the selection of the avionics vendor, I’ll have to be a bit circumspect.
First, some history about flat panel displays in the DHC-6. The first operator in the world to install glass in a Twin Otter was an Indonesian VFR operator who put Collins displays in their fleet back in the mid 1980s. They did this to get relief from the inconvenience and very high cost of repairing mechanical instruments, which had low MTBF in the hot and humid Indonesian archipelago. The next operator to install a glass cockpit in a DHC-6 was Arco in the late 1980s, who put it in a Twin Otter based in Prudhoe Bay, Alaska. Normal winter temperatures there are close to -40°.
Zimex retrofitted their entire fleet of about a dozen Twin Otters with dual Garmin 430s about 8 years ago, and there are now more than 100,000 Garmin 430 or 530 units installed worldwide. Although most of us think of these as com/nav/GPS units, these small Garmin units are actually miniature integrated FMS, and use both electronics and display panels that are similar to what is used by fully integrated avionics suites such as the Garmin 1000, Collins ProLine, Honeywell Epic and Apex, and others. The reliability of the small Garmin units is well proven, and I think most everyone will agree that they have a far, far better MTBF and MTBR than the ‘old fashioned’ radios and instruments that they replaced.
We at Viking spent almost half a year researching various avionics options for the Series 400 Twin Otter, ranging from a traditional federated instrument panel to various fully integrated solutions. The decision making process was not easy, because in addition to having to consider capital cost, one also has to consider spares quantity and cost, maintenance cost, maintenance training, pilot training, weight of the equipment, compliance with different aviation legislation worldwide, and future expansion capabilities. We at Viking were very fortunate to have the advice and guidance of our Technical Steering Committee, made up of both maintenance technicians and maintenance managers from all the companies that have ordered new Series 400 Twin Otters. In the fall of 2007, the committee met at the Viking facilities on Vancouver Island and overwhelmingly approved the decision to go with a modern and fully up to date ‘flat panel’ flight deck. This decision was made by the people who will be buying, flying, and maintaining the new Series 400 aircraft.
We have since chosen a vendor and have decided what the avionics configuration will be. Hopefully this will be publicly announced by the end of March. I can tell you today that we have chosen a very robust, mature, and field-proven system made by a vendor with a great reputation for quality, and that all of the factual data about reliability shows that MTBF and MTBR will be at least 4 times better than the same values for a legacy (electro-mechanical) system. Our vendor backs this up with a warranty that no avionics company would ever have dreamed of offering 20 years ago, when the last legacy Twin Otter was built.
The replacement cost (exchange basis) of the most expensive part on the new Twin Otter instrument panel will be less than half the price of the replacement cost of the most expensive part on the legacy instrument panel. Equipped similarly, a legacy Twin Otter would have had over 90 different components on the instrument panel comprised of about 70 different part numbers. The new Twin Otter will have less than 10 different part numbers on the instrument panel.
You know the headache avionics troubleshooting can sometimes be – the pilot records a fault, you can’t duplicate it, much less find it, when you’re working on the ground, and when you finally do manage to observe the fault, you realize that there are at least half a dozen different paths of influence that could hide the source of the problem. Imagine the difference between that and a fully integrated avionics system that automatically logs every fault – even transient ones – and then tells you exactly what LRU, or exactly what wire is responsible for the problem. Imagine the benefit of hooking your laptop up to the aircraft avionics system via a LAN cable and and the aircraft's own satellite connection and then asking the engineers who designed and built the system to have a look at an individual component (or the whole system) via internet and offer their advice before you begin work.
Vibrations are certainly a concern. We use only components that have been tested to helicopter vibration standards. Hot environments are a concern – we use components that have been proven to function up to +52°C (the operating limit for the aircraft) and won’t perish until +70°C. Heat generation is a concern, which is why we chose the newest and most modern components for the Series 400 Twin Otter – they generate a heck of a lot less heat than earlier generation systems. Heck, our flat panel displays don’t even have a cooling fan in them, because they have been proven in field use to not need one. The US Army uses very same displays in their tanks and aircraft in Iraq – we figure that if the display meets mil spec for combat use in Iraq, it should be tough enough for a Twin Otter operating off a bush strip or choppy water.
We have not chosen the least expensive system, nor have we chosen the most expensive system. We have, without any doubt, chosen the most rugged and reliable system.
I’m certain that the newest generation of Twin Otters will be far more reliable than the legacy fleet. In fact, I’ve staked both my job and my reputation on that.
Michael