Posts: 2669
Joined: Sun Jul 16, 2000 3:44 am


Tue May 08, 2001 6:26 am

I have a few questions about TCAS. First, when was it implemented? Was there a particular date when all manufactured passenger aircraft needed TCAS? Additionally, I noticed that older aircraft, for example older 757/767 photos, show a vertical speed indicator like a clock-style instrument. However, most of the photos I see nowadays have the integrated TCAS and VSI. What company manufactures this gauge? Does this company have a monopoly in this market? Were these "new" gauges installed on the older aircraft? Who made the decision to place the TCAS gauge with the VSI? Do aircraft with ND's have the TCAS in the ND? Thanks for any help!
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: Tcas

Tue May 08, 2001 6:29 am

Some older aircraft use the VSI to display Resolution advisories (RAs) in the for of those red/green lights lining up at a certain rate of climb. Most aircraft with EFIS (including the newer 757s/67s) use the ADI to display the RAs.
Posts: 91
Joined: Tue Mar 13, 2001 8:03 pm

RE: Tcas

Tue May 08, 2001 10:23 pm

tcas had to be installed on the majority of a/c by 1993 but most operators had finished their instalations by the end of 92. allied signal are major players with tcas and have a few publications about the system and the way it works and has developed over the past 9-10 years. now tcas is intergrated int things like EGPWA (which allied signal also make) so ther eare variouse ways that it is displayed but this is all down to the system that the operators have installed on their fleets.
hope that this has gone part of the way to answereing your question, regards tuffty Smile
Posts: 75
Joined: Sat Apr 07, 2001 3:14 pm

RE: Tcas

Tue May 08, 2001 11:33 pm

TCAS was first made mandatory in the USA.
Here in Europe the TCAS was made mandatory from the 31 march 2001 (but some airliners has got a new deadline due to problems during installation)

The first certified system was called TCAS, Traffic Collision Advisory System, and whats in use today is TCAS II.

Here in Europe the TCAS has also got Called ACAS (Airborne Collision Advisory system) this is due to that the JAA has gone for a software that by the present time is version 7. System are fully compatible with each other. The afterinstallation systems with IVSI are often called ACAS

There are two different layouts in the cockpit.

The factory installed one:
TCAS info are displayed on the EHSI or The ND display, Resolution Advisory info on the PFD or EADI.
This is the best way to display the info.

Then there are the afterinstalled one.
If the airline does not go for a full retrofit to the factory installation (expensive). This would require, new Symbol generators, complete new wiring up to the displays and so on.

If the wiring wasnt there from Boeing, Fokker or MD, then there is another (cheaper) option.
You install two ATC mode S transponders (If not allready onboard the A/C) two Tcas antennas, one on top of the fuselage and one at the bottom. Change the ATC control panel to a ATC/TCAS controll panel. a TCAS/ACAS computer add some wiring in the e&e and up to the flight deck. And instead for the VSI indicator you install a IVSI (Integrated Vertical Speed Indicator) that are able to display both VSI and TCAS info and Resolution Advisory.
A small display and it will give you the info you will need.

The audio alert that the TCAS will give are heard in the cockpit roof loudspeakers, not able to mute or adjust volume on. This is the same for both factory installed or afterinstalled TCAS/ACAS.

Hope someone understand my explanation.
Atle  Smile/happy/getting dizzy

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