Twin Otter/ PFD Displays.

[hoggsnortrupert]

The DHC-6 in my humble opinion is a truely remarkable A/C from the point of view of its robustness, and ease of field maintainence.

It is a machine that I am pleased to say I am very fond of.

It is used in many area's around the globe, from Water/Floats, Coral, Stone, Sand, Grass, Gypsum, and Paved surfaces.

Alot of these sufaces have vibration frequencie's that cause the instrument panel to shake somewhat, and this frequecy varies hugely dependant upon the condition of the strip, and its surface.

Last week a brand new machine ( of another type) was grounded becuse of a failure of a PFD screen, due to the failure of a cooling fan.

The replacement part was only available ex USA, and only then after 3 days, the wrong part arrived? another few days and another was located from another source.

These parts apparently were very pricey indeed for what they were.

Now I understand that the NEW VIKING TWIN OTTER is being built to save weight with PFD screens and going away from the Analog instrumentation that alot of these countries in very remote locations operate.

I wonder if this will detract from its robustness and ease of maintainence in these locations, IE in the pacific attracting experianced engineer's has always been an issue, and always will be.

What will this mean to spares, engineering skill, down time "COSTS", and spares carried at what cost? in comparisim to Analog?

Engineers opinions please.

Chr's
H/Snort.:ok:

[hoggsnortrupert]

Didn't think it too dificult for a decent Engineer! Does this leave me to believe that its being bought into service without this being considered?:(

89 views: and not one available to answer what I would have thought a basic
Question that would have already been addressed, Wot does this say about the product?:(

Answer's or opinions still welcome.:ok:

Chr's
H/Snort.

[speedrestriction]

May be worth asking this on the Biz Jet forum where PC12 / Kingair guys post. PFDs and MFDs (interchangable unit) on DHC8D very occasionally give grief, usually on the first sector of the day until the aircraft warms up.

sr

[jazz-sparky]

Well, Hoggs, maybe that brand-new/old-designed Twin Otter should be tried a couple of years before having a real idea of the avionic on it.
Helicopters are full of "delicate" instruments now, same for a lot of military transports: things break, things get fixed.

Thats why we are here...

As long as they don't go for the cheap new electronics... :mad:

[V1... Ooops]

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

[Toubob]

Hey Michael;

The new machine sounds great. I am sure I flew with you once ex Hassi
in June 98 in LQV.

The new PFD's would be great if they have an EFIS similar to the 1900D.

One where you can get a LOC like display of a GPS course with raw data NDB overlaid. The majority of bush approaches being NDB or home made GPS, this would help out greatly. Hopefully also tied into a Flight Director.

I would love to try out the new machine some day, but fear my Twotter days are long behind. I am tied to an A340-600 now, but still miss what I think is the best airplane I have ever flown.

Cheers.

[hoggsnortrupert]

Thank you for your insight Michael:

I have no question as to the benifits of utilising PFD's:

My Question envolves operators in remote locations, Africa is hardly of comparisim in regard remoteness to some obscure island in the Pacific that relies on the twotter for a once weekly service, and is serviced at its home base by engineers without the rescource to computors, or electrical path fault finding.

(IE: They understand analog, they have another gyro on the shelf)

The logistics envolved in a recovery, or repair, even replacing a battery that has decided to quit under load on a remote start, is a substantial effort.

Alot of these companies, (Airlines) run by small countries that rely on income from Tourisim, & Aid donation, or selling their vote to a UN member country, do not have the expenditure.

Alot of these companies (Airlines) operate from a paved surface one end, a oceanic sector with either NDB navigation, and GPS, to a Sand, Coral, Grass, Dirt, Broken rock type strips.
These strips range from Sea level to 8000 ft Amsl, ( I believe in Nepal they have one at 16000ft) to one way 300 mtr uphill: I mean “uphill” hardly a slop.

Also worth a mention is the fact that on some strips the landing is a very very precise affair, on the ground on the “X” and Beta/Reverse simultaniously with Heavy Breaking, on a surface that shakes the living crap out of you and the machine.

They have relyed upon this fantastic product (All series including vista liner series) that has constantly delivered outstanding service over alot of years.

And hope to have continued support to enable ongoing operations.

I cannot help but think this PFD thing, will not suit all, thats all I am saying, and I feel it would be good, (excellent in fact) if the analog was still on offer with the newly developed model.

I have been taking an interest in the intergration into service of a couple of helicopters, AW 139's: And have seen and witnessed the problems associated with PFD failure.

Now a slight correction is in order: Zimex did not replace their entire fleet 8 years ago with Garmin 530's, as of 2002-2004 they had two:

One of these lost its interface and the whole unit failed?

Their fleet of Twotters had its IFR capability withdrawn by FOCA, but we won't go there! (wern't allowed to let the client know) The only ones FOCA gave IFR certification two was the ones with the 530s, and as I say one lost its interface in total.

As for heat, Carrier Airconditioning company had problems with their airconditioners as supplied rated to 55 deg's C , to a client company down Krechba & Teg, they came down and redesigned the compressors for these units after recording the temperature at 63 deg's C : only 7 deg's away from your max.

Now the military in Iraq, that operate the same PFD's in the heat, do not suffer the heat soaking that these Zimex aircraft suffer, because of the military servicing and maintainence procedures they routinely use, that Zimex does not have and will never ever be able to adopt or implement:

I feel that Viking have to be certain that what they are dealing with is "apples" and not confusing them with oranges:

I have seen a very good product IE: Casa 212, suffer operationally due to in my opinion to having an engine fit being unsuited for its remote roll, if this product had a pair of PT 6's on each wing the Otter would have been out classed along time ago.

Twotter is with doubt, a bloody great machine, I am very fond of it, I have 11500 hrs on “all” series, in most operations with the exception of on Ice, and I hope to do that one day, in saying that, I spend my time at a desk more than I should, and hope to be able to spend more time on the Twotter in the future.

I only hope you guys at Viking understand the way the machine is operated in other parts of the sphere, and don't screw the pooch and be left with a lemon.

Chr's
H/Snort:ok: