2
$\begingroup$

I know that the TCAS II system has a lower antenna which can be either omnidirectional or directional. How does the functionality of the system change? If the antenna is omni then I think / assume that it cannot know the bearing of an intruding aircraft and therefore can not provide data to position it on a display. Is it only used for transmitting interrogation and/or receiving other data?

Thanks,

Ori

Improve this question
$\endgroup$
1
$\begingroup$

The directionality of a TCAS antenna is ONLY used for positioning the bogey on the TCAS display, it is NOT used for determining time-to-contact. So you're still going to get TAs and RAs from the Omni antenna even if the upper antenna is blanked, but you won't get the display of that traffic.

Improve this answer
$\endgroup$
1
  • $\begingroup$ Thanks for your answer. My question is what would happen if the lower (omni) antenna is partially obstructed. The upper (directional) antenna is not obstructed. $\endgroup$
    – user1412867
    Jun 27 '19 at 9:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.