Tcas Abs & Rel

[NSEU]

A question was posted on another aviation forum regarding the use of RELative and ABSolute TCAS control panel settings. When is ABS used, operationally? (On aircraft with this option).

Thanks in advance.
Rgds.
NSEU.

[BOAC]

We do not have that setting on BA 737s, NSEU - could it be the same function as our 'push-button' which gives actual altitude rather than relative displacement?

Useful when your mental arithmetic is slow

[NSEU]

"could it be the same function as our 'push-button' which gives actual altitude rather than relative displacement?"

Sounds like it, BOAC.
You have a similar system on your 747-400's, but the ABS (or "F/L") switch appears to be momentary and won't allow the system to remain in that display mode, so I imagine this is not something you would use a lot(?).

Rgds.
NSEU.

[BOAC]

No - personally not a lot, and it is a 'while the button is depressed' function on the BA737. Sometimes useful for a quick assessment of probable cruise levels available - without too much mental 'a'

[bakedbean]

Absolute and relative functions were available on the Dash 8 but I personnely never selected absolute. It would though be usefull on arrival into a busy airport such as Gatwick combined with the Below function to help you antisipate your descent profile. There was one of the toys I might have used better with hind sight.