Real Answers from Real Pilots

TCAS questions

(Merwan) #1

Okay, this is going to be a little bit longer than average.
Please feel free to correct any assumptions or unrealistic hypothesis before answering.

The FAA mandates part 135 and 121 carriers to have TCAS II installed in every aircraft (if certain conditions are met), but TCAS is not mandated for GA aircraft nor private jets (Does this still apply? most likely.)

Now to my questions:
1- If you are in an IFR flight plan, does that mean you are in flight following (or at least getting traffic advisories) automatically or you still need to ask for it? is there any chance that you don’t get it?

2- If it is clear and an airliner is flying VFR bellow 18,000F for a short trip, is it still required to file IFR flight plan or it would be a VRF flight plan.

3- Let’s assume an airline pilot in-flight is not in contact with ATC like having the wrong radio frequency (or any other reason), How would she avoid a collision with a conflicting private jet - merging from 8 o’clock at the same altitude - which has no TCAS compatible transponder?

4- For two piston GA aircraft, see and avoid is realistic, but for two conflicting jets, I think the odds of survival are slim. with that been said, in the absence (or malfunction) of the TCAS, is there any other “Human free” alternative advisory?

Sorry for the long list, I hope you enjoy answering!



You are correct that TCAS is not required for private jets or GA aircraft. I am under the belief that many private jet owners do chose to equip their airplanes with TCAS, but I cannot say that for certain.

  1. Being on an IFR flight plan means that traffic advisories and aircraft separation will be provided in all phases of flight, it does not need to be asked for.

  2. Airliners always file and fly on IFR flight plans, regardless of the weather, altitude or route.

  3. While the private jet might not have TCAS, it will have a transponder. Our TCAS equipped airplane will still be able to issue traffic advisories and show us where the other airplane is, but it will not be able to issue what we call a “resolution advisory” which is when the airplane tells us to climb or descend.

  4. No. We rely on TCAS or ATC issued advisories.

At my airline, we can only fly an airplane that has a broken TCAS inside the US. We do not allow them to leave FAA airspace as other countries simply do not provide the level of protection to aircraft that the FAA does.


(Merwan) #3


Thanks for the responses.

From point #3, where does ADS-B fits in here ? since it is relatively new technology (Around 10 years old) I don’t expect most airliners to have it installed already.
Is the current TCAS able to receive and process the current ADS-B signal as well ? and still no resolution advisory too ?



TCAS and ADS-B operate completely separately from each other. I am not aware of any airliners that use ADS-B for traffic advisories.




Actually all our (Hawaiian’s) Airbus A330’s and 321 Neo’s have ADS-B already installed. Cheaper to get it new from the factory than to retrofit later. Very useful for in-trail spacing over the Pacific.


(Merwan) #6

Thanks Chris and Adam.