Bell 412 with Avidyne TAS 600 series

[Dave Ed]

Bell 412 Avidyne TAS 600 series

Hi all. Been a while since I posted on Pprune. Something technical this time.

I am interested in operator’s experiences of the Avidyne TAS 600 series Traffic Avoidance System as fitted in the Bell 412 and maybe other helicopters for comparison. Avionic engineer’s inputs would be useful with regard to antennae locations and extra ground plane work.
The reason I am asking is that after fitting the TAS 615 with MFD 600 display we are struggling to meet customer’s expectations of reliable bearing accuracy.

Functioning system with IFR 6000 test set, bearing checks with local traffic and suppression checks with transponder test sets all show systems to be serviceable.

Compared to “clean”fixed wing aircraft it is difficult to obtain the optimum antennae installation that provides line of sight communications between host and target aircraft. Antennae ground planes provide an additional challenge especially when mounted on composite panels.

The pilot’s guide quotes bearing errors of +/- 30 degrees, worse behind aircraft due to antenna masking and loss of targets and targets fragmenting due to a whole host of other reasons.

So any goodor bad experiences out there?

[Flying Bull]

Hi Dave Ed,
we use Ryan TCAS on a different manufacture helicopter.
After initial problems, the top antenna, mounted on a hydraulic cover - as well as the bottom twin antenna, mounted under the nose got big extra copper attached (the hole of the hydraulic cover has a thin copperfoil inside as well as the nosesection.....)

[hueyracer]

What aircraft are you using?

Some of the Ex-Offshore/Military 412´s were painted with paint containing metal particles.
This paint reduces the accuracy/reception on weather radar and/or TCAS (or other installations where the antennas are installed behind the frame)...

Or is your antenna un-obstructed?

[Flying Bull]

Hi hueyracer,

BK117B2 and BK117C1 we have

https://app.box.com/s/901w016nfqoifw4fvu99l3jgmnx7xq6o

https://app.box.com/s/9zmgxz18knh1wdr0bilaroclf7hvxa0o

[Dave Ed]

Not really at liberty to say the operator of the aircraft. You know how touchy management can be! Like the paint idea. Will check that out. Obstructed antenna definitely.


Our lower twin blade (bearing antenna) is surrounded by wire strike, FLIR disconnects, other antennae, then further back skids and the Big float bags.


We also have a lot of added copper foil under the top single blade antenna on the composite racing car fairing.


Flying bull.


Great pic of that lower twin blade antenna on the BK117.
I presume that there is an added ground plane inside the composite radome.
Is your installation performing well?

[Flying Bull]

Hi Ed,
I seldom see the nose dome removed - "benefit of working on a remote station ;-)"
The installation is mostly performing well - with sometimes a 180 degrees hickup in bearing, which is hard to reproduce - but if I don´t see conflicting traffic in the direction pointed out, I´ll have in mind, that someone is sneaking up behind.
Whats really helpful, is that the system is linked to our "helimap", an GPS based MAP-System, so that I can see the little filled (may be conflicting) or black (non conflicting / altitude) squares on the map and can search for the traffic with regards to landmarks / towns / streets. (but the mapdisplay it is only working correct while flying forward - hovering sideways or backwards means, that only the tiny Ryan-screen is correct)

[GipsyMagpie]

I have flown with TAS 600 series TAS on a variety of platforms with a variety of displays. I've some perform as per the manual and some perform terribly (180 Deg out, terrible range etc).

one thing that we found was that there are 2 levels of test in the manual. the primary test gave false serviceable results but the deeper test found hidden faults (primarily with the LRU) that manifested to the pilot as poor bearing resolution.

Once resolved we've had some good service out of the TAS linked to various polar or map displays. I agree that a map background is best so you can relate the range to ground features. Unfortunately we have some airframes fitted with a text based 1/2 ATI display which is diabolically awful. We also have some Neanderthal aircrew who insist that avionics are the devil's work and pilots must not look at them (hence the text displays when polar ones were available). I believe there is even one airframe where the handling pilot has to turn off his screen so he cannot look at it (the co-pilot has one too fortunately).