Approach Fast Stack

I can not see the real benefit of this product, I do see disadvantages though.

Some quotes from there website:

Approach Fast Stack’s modular wiring system interconnects avionic components with a central hub and ready-build cables (all cables are double shielded and grounded at the hub eliminating the possibility of ground loops)

Using double shielded wiring seems to be a good idea. I don’t like their idea to prevent ground loops. How the shielding behaves depends largely on the shielding methode (single or both ends).
Basically for low frequencies such as audio the electric field is the problem. A single point shield will work here well. For protection against electro magnetic fields (RF) shielding at both sides is needed. Using shielding at both sides a groundloop does exist. This doesn’t have to be a problem. If it causes a problem, their is common mode current on the wiring. There are other ways to solve this problem, using ferrite for example.
Protection against electro magnetic fields is not possible with single point shielding.
IMHO they adress a problem, but use the wrong solution. This is also against all installation manuals which require double sided shielding on both ends for other than audio wiring.

Approach Fast Stack eliminates time and errors caused by the hand wiring methods used today

Approach Fast Stack make custom made wiring depending on your aircraft configuration and wiring lengths. IMHO their argument is invalid as their is no difference between any good avionics engineer making a hand made / custom bench wiring loom for you, or approach fast stack making their hand made wiring.

I also doubt the saving on time using this system during a retrofit. Do not forget the wires go everywhere, and now have to go from their box to everywhere. It might save some time on a complete new aircraft (homebuild), but even then I doubt if their is much advantage.

Then it adds extra connectors etc, which are always the weakest point of any installation, so it adds more possible failure points. I wouldn’t recommend to go this route.

It’s interesting but I would have thought there would be too much variation between installations, not least because most avionics installations (of any substance) are done to “old” aircraft.

Also, IME, any cable harness which can be made up outside the aircraft is quite quickly made up on a bench, and doesn’t represent a lot of time as a % of the total installation time.

Protection against electro magnetic fields is not possible with single point shielding

I think that protection against a magnetic field is impossible anyway. It will penetrate any non-ferrous metal. Only something like a mu-metal shield will stop it. So one has to avoid creating loops which – by virtue of having a “loop area” – can radiate a significant magnetic field.

I think that protection against a magnetic field is impossible anyway. It will penetrate any non-ferrous metal.

This is incorrect. Note that this is an RF electric magnetic field. If those would penetrate non ferrous metals, suchs as aluminium, you would also be able to use antenna’s inside your aircraft just like some composite aircraft. That is not the case. You can stop RF with a wide range of metals.

How the shielding behaves depends on the electrical length of the shield versus frequency. This is why for low frequencies single shielding can be used. The only disadvantage of multi point shielding is the possibility of ground loops, but these can be stopped using ferrite for example.

Most EMI / EMC problems are related to incorrect shielding / wiring routing and the lack of knowledge on this subject and the use of test equipment.

Recently seen again, with a stormscope system, which was installed without correct practices for EMI leading to installation with cells indicated all over the display.

I’ve installed the Fast Stack and worked with them on a couple of installations.

My observations :

- Their cables are absolutly First Class, the best I’ve ever seen and each comes with full computer generated schema/build sheet;

- They can supply be-spoke cables of same high quality yet excellent pricing;

- As mentioned, the Hub requires more cables & connectors over direct appliance to appliance cabling;

- The hub takes up room in an already cramped environment ( Mooney for example ) , not to mention the additional cables;

- As a company, they are a class act and I was very impressed wit their service.

My 2 cents …

There is another angle on this:

Most avionics installers don’t actually understand equipment interconnections. This is not made easier by most not being pilots, let alone IFR pilots.

I know one installer who has done maybe 100 GNS430/530 boxes and none of them have the HSI course pointer wired back to the GPS, so using the GPS in OBS mode needs the OBS set on the GPS. I guess this is also a comment on how many pilots know how their avionics work….

Most installers start on the back page of the IM and thumb the pages backwards until they find one which resembles the desired configuration. If it doesn’t work, no problem, you telephone Garmin! I have used a load of UK installers and there is only one guy I have met who actually understands the signals (XYZ/400HZ, RS232, ARINC429, Gray code) and the integration.

I have no reason to believe the issue is hugely better in the USA, though it probably is better because a given shop out there will be doing a lot more business, and US pilots have effective and informative forums (where they don’t hack each other to death like they do an all European GA forums – except EuroGA) so a good shop gets more business and a bad shop will quickly lose business.

So there is clearly room in the market for a “plug it all in” solution. But, IMHO, rather for the wrong reasons

I know one installer who has done maybe 100 GNS430/530 boxes and none of them have the HSI course pointer wired back to the GPS, so using the GPS in OBS mode needs the OBS set on the GPS.

Wow, that is supposed to work? I have to try that soon

Wow, that is supposed to work?

My previous GPS (Trimble) didn’t even have the possibility to wire back the HSI course pointer…

Peter – I’m sure even YOU would be impressed with Fast Stack owner’s – Tom Hass prowess.

I am just a simple bloke. I don’t know what makes you think I am hard to impress

Give me a soldering iron and a straightforward gurl and I am as happy as a pig in sh*it