Avionics Upgrade

Because of moving from Tanzania to Australia and everything that that involves, our blogging has been quiet for some time. So time to try and catch up a little with things that have happened between our last blog (back in October I think) and now ...

So, I thought that it was time for me (Mark) to write something about the work I had been busy doing in the hangar the first part of 2014. MAF have decided to upgrade the avionics in all of the C208/B Caravan/Grand Caravan aircraft in Africa. This means that all the old dial indicators will be removed and be replaced by multi touch screen displays.

OLD AND NEW DISPLAY

Tanzania were very fortunate to have been selected to do the very first installation on their aircraft 5H-ZBZ, and I have been the lead mechanical engineer on this whole job. There are many different parts to this project and being the very first aircraft, a lot of lessons to learn.

Sitting on top of ZBZ installing antennas

The circuit breaker panel had to be re-done for al the new avionics units. Which also meant that we could clear out a load of redundant wires at the same time. (It's amazing how many redundant wires there are in aircraft, and the weight gain that can be achieved by removing these from the airframe).

 

As the new system has many new avionics boxes, I had to design, fabricate and install new avionics shelves that would be strong enough to pass the critical 'G' load (simulated G-force to prove the shelf will not fail in crash).

The next set of photos shows a shelf that was already installed with a KN-63 DME (Distance Measuring Equipment) unit, and what I did to modify it to hold the new GTX-33 Transponder unit as well as the original DME.

Original Tray and DME Unit

New Transponder and Original DME Unit with the new tray

The next tray to be fabricated was installed below the DME/Transponder tray and holds the new GAD 43e Adaptor and the GDC 74A Air Data Computer. The old tray had to be removed and then remade from a thicker material to meet the Garmin requirements.

The next unit, the GRS 77 AHRS (Attitude and Heading Reference System) unit. This unit has to be installed so that it is zero degrees in both latitude and longitude during level flight. This meant that we had to install a fake floor underneath the floor below the co-pilot seat. It was a challenge to get it fit right, but as you can see from the digital protractor, I got it right.

At the back of the aircraft, we had to install the units for the GRA 5500 Rad Alt (Radar Altimeter) and the GTS 800 TAS (Traffic Advisory System) along side the existing WX-500 Stormscope unit. I created a new shelf for the very heavy TAS unit, and the Rad Alt fitted next to the Stormscope.

One other unit to be installed was the GMU 44 Magnetometer in the right wing. There was already a mount for the old unit in the wing. MAF US had created a jigging tool that helps convert from the old style unit to the new which helped a lot.

Then there were all the new antennas that needed to be installed all over the aircraft (as well as existing ones that had to move location because of proximity to other antennas. I installed at least eight new doublers and antennas as well as moving two to new locations.

Lastly, but definitely not least, the change of the instrument panels and radio stack to install the GDU 620 Display Units, GTN 750/650 Touchscreen GPS/Nav/Comm/MFD units, GMA 35 Audio Panel, IndigoOne Satellite Tracking, EFD1000 Display and the ESI-1000 Emergency Standby Instrument. New panels were cut in Australia by a water-jet cutter. Once they arrived, there were a few minor adjustments, then the instruments were installed and connected to the newly installed wire looms.

In the end, we got everything installed and after a few issues with the avionics not talking to each other, and doing the configuration set ups, it all worked perfectly. As you can see it was quite an involved process, which we repeated on another aircraft in Dodoma (5H-OPE), before MAF started the upgrades in Kampala, Uganda.

The team with the finished avionics behind
(A mix of English, Australian, Swedish and Tanzanian)

As a testament to the amazing new avionics, this aircraft has just made a nine day journey from Uganda to Australia (via Ethiopia, Djibouti, Oman, India, Bangladesh, Myanmar, Malaysia and Indonesia). Very soon, this Cessna 208 Caravan will be serving MAF in Arnhem Land.