timh4000
Topic Author
Posts: 239
Joined: Fri Dec 07, 2018 1:14 pm

TCAS/ATC

Mon Dec 02, 2019 10:56 pm

Let's say you are on approach at 5000ft, zero visibility TCAS Announces TRAFFIC, CLIMB at the same time ATC warns of the same and says descend. Which action do you take?
 
GalaxyFlyer
Posts: 4095
Joined: Fri Jan 01, 2016 4:44 am

Re: TCAS/ATC

Mon Dec 02, 2019 11:11 pm

 
User avatar
Starlionblue
Posts: 19480
Joined: Fri Feb 27, 2004 9:54 pm

Re: TCAS/ATC

Mon Dec 02, 2019 11:52 pm

Always, always, always follow a TCAS RA. And while we tell ATC that we have an RA. we are encouraged not to transmit what TCAS is telling us to do, in order to avoid confusion. Once TCAS says "Clear of Conflict", we tell ATC our position.

TCAS knows best.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
User avatar
zeke
Posts: 14140
Joined: Thu Dec 14, 2006 1:42 pm

Re: TCAS/ATC

Tue Dec 03, 2019 12:19 am

Starlionblue wrote:
Always, always, always follow a TCAS RA.


You mean you don’t keep flying the approach and ask ATC what to do ?
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
User avatar
Starlionblue
Posts: 19480
Joined: Fri Feb 27, 2004 9:54 pm

Re: TCAS/ATC

Tue Dec 03, 2019 12:42 am

zeke wrote:
Starlionblue wrote:
Always, always, always follow a TCAS RA.


You mean you don’t keep flying the approach and ask ATC what to do ?


Yes, well, that was an interesting story. Typically asking ATC instead of following an RA leads to yelling on the flight deck or in the sim. I'm not fond of that.

BTW I should qualify my earlier statement. Always follow a TCAS RA unless you also get a stall warning, EGPWS warning, or windshear warning.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Yikes!
Posts: 338
Joined: Sat Oct 13, 2001 4:51 pm

Re: TCAS/ATC

Tue Dec 03, 2019 2:06 am

This says it all:

https://www.skybrary.aero/index.php/T15 ... many,_2002

Eurocontrol prohibits air traffic controllers from overriding TCAS alerts. Possibly the same here in North America.
 
N737ER
Posts: 7
Joined: Sat Jan 20, 2007 5:04 am

Re: TCAS/ATC

Tue Dec 03, 2019 4:29 am

In the US, ATC is not allowed to override the TCAS RA. Simply, all ATC can do is call traffic, and make sure no other aircraft may be affected by the RA. Some airlines have policies where if the crew has the offending aircraft in sight (hopefully ATC has called traffic before the RA happens) they can disregard the RA if ATC has applied appropriate separation. The aircrew will notify ATC when the RA is resolved.
 
IAHFLYR
Posts: 4094
Joined: Sat Jun 25, 2005 12:56 am

Re: TCAS/ATC

Tue Dec 03, 2019 2:54 pm

As a former TRACON controller it is very difficult to not respond when the crew informs you of an RA.

But from the order 7110.65Y here is the rule:

2−1−28. TCAS RESOLUTION ADVISORIES
a. When an aircraft under your control jurisdiction
informs you that it is responding to a TCAS
Resolution Advisory (RA), do not issue control
instructions that are contrary to the RA procedure that
a crew member has advised you that they are
executing. Provide safety alerts regarding terrain or
obstructions and traffic advisories for the aircraft
responding to the RA and all other aircraft under your
control jurisdiction, as appropriate.
b. Unless advised by other aircraft that they are
also responding to a TCAS RA, do not assume that
other aircraft in the proximity of the responding
aircraft are involved in the RA maneuver or are aware
of the responding aircraft’s intended maneuvers.
Continue to provide control instructions, safety
alerts, and traffic advisories as appropriate to such
aircraft.
c. Once the responding aircraft has begun a
maneuver in response to an RA, the controller is not
responsible for providing approved separation
between the aircraft that is responding to an RA and
any other aircraft, airspace, terrain or obstructions.
Responsibility for approved separation resumes
when one of the following conditions are met:
1. The responding aircraft has returned to its
assigned altitude, or
2. A crew member informs you that the TCAS
maneuver is completed and you observe that
approved separation has been reestablished, or
3. The responding aircraft has executed an
alternate clearance and you observe that approved
separation has been reestablished.
Any views shared are strictly my own and do not a represent those of any former employer.
 
hitower3
Posts: 117
Joined: Fri Oct 21, 2016 9:55 am

Re: TCAS/ATC

Wed Dec 04, 2019 6:36 pm

Interesting topic, which lets me ask one more question:
Is there any automated way for the ATC controller to be made aware of an ongoing TCAS RA? Or do they depend on a radio call by the pilots flying the RA procedure?

Best regards,
Hendric
 
hitower3
Posts: 117
Joined: Fri Oct 21, 2016 9:55 am

Re: TCAS/ATC

Wed Dec 04, 2019 6:39 pm

Interesting topic, which lets me ask one more question:
Is there any automated way for the ATC controller to be made aware of an ongoing TCAS RA? Or do they depend on a radio call by the pilots flying the RA procedure?

Best regards,
Hendric
 
sccutler
Posts: 5831
Joined: Thu Jan 27, 2000 12:16 pm

Re: TCAS/ATC

Wed Dec 04, 2019 6:42 pm

hitower3 wrote:
Interesting topic, which lets me ask one more question:
Is there any automated way for the ATC controller to be made aware of an ongoing TCAS RA? Or do they depend on a radio call by the pilots flying the RA procedure?

Best regards,
Hendric


TCAS is an autonomous system, and it works from its own interrogation of other aircraft. There is no data link to controllers' scopes or systems.
...three miles from BRONS, clear for the ILS one five approach...
 
hitower3
Posts: 117
Joined: Fri Oct 21, 2016 9:55 am

Re: TCAS/ATC

Wed Dec 04, 2019 6:53 pm

sccutler wrote:

TCAS is an autonomous system, and it works from its own interrogation of other aircraft. There is no data link to controllers' scopes or systems.


Dear Sccutler,

Thank you for your quick answer.
Indeed, one of the main reasons for the Überlingen disaster was a conflicting instruction from ATC. Even though priorization rules exist (as explained here above), it would be sensible to include ATC in the TCAS resolution process, IMHO.

Best regards,
Hendric
 
GalaxyFlyer
Posts: 4095
Joined: Fri Jan 01, 2016 4:44 am

Re: TCAS/ATC

Wed Dec 04, 2019 10:28 pm

They are included, Pilot transmits, “TCAS RA”; ATCO waits for Pilot to say something like, “clear of conflict”. Remember on many RAs, one of the targets isn’t communication with ATC or is likely not on an IFR flight plan.
 
User avatar
AirKevin
Posts: 518
Joined: Wed Apr 26, 2017 2:18 am

Re: TCAS/ATC

Wed Dec 04, 2019 10:42 pm

hitower3 wrote:
Indeed, one of the main reasons for the Überlingen disaster was a conflicting instruction from ATC. Even though priorization rules exist (as explained here above), it would be sensible to include ATC in the TCAS resolution process, IMHO.

Except that actually didn't help in this particular instance. The DHL crew tried to let the controller know that, but as he was working two separate radars at that point, he missed this. It also didn't help that the main radar was undergoing maintenance, so there was no functioning collision alerter as a result of this.
Captain Kevin
 
rendezvous
Posts: 541
Joined: Sun May 20, 2001 9:14 pm

Re: TCAS/ATC

Thu Dec 05, 2019 8:40 pm

a TCAS/RA is an emergency warning, a last line of defence. You do not ignore warnings. Just like you don't ignore a "terrain pull up" alert.
The newer A320s I fly have autopilot TCAS - it will fly the RA for you.
 
HTCone
Posts: 139
Joined: Sun Jul 16, 2017 7:10 pm

Re: TCAS/ATC

Sat Dec 07, 2019 1:03 pm

Pilots follow TCAS RAs, not us. Period. It may have been our error which caused the issue.

I’ve had 2 RA situations in my sector over the years, thankfully neither my fault. A 767 1 mile behind and 2,000 feet below a 777 needed a 1,000 foot climb for his Oceanic entry, he got an RA after climbing about 800 feet and descended again, the 777 only got a TA. The other was a GLF5 departing an aerodrome who I cleared up to FL350, 1,000 feet below an opposite direction B744. I warned to GLF to reduce ROC 3 times as he got through the high 20s and gave traffic info to both him and the 747, still he set off RAs.

Interestingly there was an issue a couple of years ago I’m aware of where a conflict was developing, controller gave avoiding action but the crew he gave it to ignored the turn because they had a TA, mistakenly believing TAs override ATC avoiding action. RA soon followed.
 
71Zulu
Posts: 1883
Joined: Mon Aug 28, 2006 12:42 am

Re: TCAS/ATC

Sat Dec 07, 2019 4:09 pm

Incident and close call with JAL in 2001.

[MEDIA=youtube]1V-NURlZ0Jc[/MEDIA]



Sent from my SM-N960U using Tapatalk

Who is online

Users browsing this forum: Gingersnap, WildcatYXU and 9 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos