Tcas question

[ppppilot]

Thanks MIN-JUMBO.
Everything you said is correct.
The second part of the question is “Does all the TCAS II needs hdg pitch and roll inputs?”
Pitch, makes sense to me, because when you are in an RA, the pitch input is used to know your vertical status, and compare it with the ROC/ROD proposed to solve the situation. Therefore you can receive a “Climb/Descend”, “Increase rate of descend/climb”, etc. msg.
Hdg and roll seems to be useful in order to know if there is a real risk of collision. In other words, TCAS must know where are you flying to calculate which of the traffics around you, are potential risks.
Not only that. If the IRU doesn’t work then it makes sense that it can not be displayed anything because PFD and ND associated are not working, as far as you don’t change the source of information (IRU).
The source for the hdg, pitch and roll, can vary between ADIRU, HSI, ADC, etc. It is not important to the question till here.
But now going into Airbus and ADIRUs. A318/A319/A320/A321 ATA 3.02.34 page 7. A330/A340 same ATA, page 4A or 5. Abnormal Procedures-Navigation-NAV IR FAULT. There is a note saying “In case of an IR1 fault, the TCAS may be inoperative, depending on the TCAS manufacturer”
In case it were only be affected the RA it should concrete on that fail, but it says all the TCAS and that includes also the traffics display and the TA.
Do that means that many of the TCAS needs hdg, pitch and roll to calculate the position of the traffics?
I thought that position was calculated by means of time of the radio signal to return-àdistance, mode c altitude report-àvertical separation, and directional sensing antenna-à bearing. Then you could have at least the presentation of the sensed traffics in case of not hdg, pitch and roll inputs
ADMIRAL, sorry if I was not clear enough.
Tailwinds