Questions tagged [tcas]

Traffic Collision Avoidance Systems warn pilots about other, nearby aircraft that may be a collision risk

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21
votes
3answers
24k views

How does TCAS work?

TCAS is obviously a fantastic piece of kit, but I was wondering: exactly how does it work? What I mean is, how does it determine whether to tell a pilot to climb or descend when there's traffic? ...
20
votes
2answers
1k views

Are controllers aware of TCAS RA taking place?

When the TCAS issues a Resolution Advisory (RA) which contradicts an ATC instruction, the RA takes priority. Are controllers aware (notified on their screen) that a RA has been issued between two ...
17
votes
1answer
671 views

Can TCAS cope with situations involving more than two aircraft?

Most of the information I've seen about TCAS talks about only two aircraft being involved. It's pretty unlikely, although far from impossible that situations involving three or more aircraft may ...
16
votes
1answer
16k views

How is a near miss defined?

With respect to mid-air collisions, how is a near miss calculated, detected, and reported? Does ATC have radar detection, or is it strictly up to pilots to report a close encounter with another ...
13
votes
2answers
1k views

When receiving a TCAS RA, DESCEND DESCEND, and starting the descent, if a pilot received GPWS warning, TERRAIN, what would they do?

The TCAS warning says: " DESCEND, DESCEND" and immediately after the crew receives: "TERRAIN, TERRAIN", what would they do?
12
votes
2answers
2k views

How is a conflict between aircraft with TCAS I and II resolved?

Let's say there are two aircraft in a risk of collision, one of them is equipped with Traffic Collision Avoidance System (TCAS) I so it will get only a Traffic Advisory (TA), however the second one is ...
12
votes
1answer
2k views

Another airplane almost hit me, but an ACAS Resolution Advisory told me to climb first. Now what?

So when a pilot is flying along and suddenly hears a "Climb... Climb..." Resolution Advisory (RA) from ACAS/TCAS, we are trained to immediately climb to avoid a collision with another aircraft. ...
11
votes
1answer
4k views

What is the range of TCAS?

The traffic collision avoidance system has two versions, TCAS I and TCAS II. I know for sure that TCAS I has a range of 40 nautical miles, but what is the range for TCAS II?
10
votes
3answers
1k views

Would TCAS ever issue a “climb, climb!” RA that would stall a jet with a low airspeed?

As a for instance, let's say there are 2 jets going at low airspeeds (close to $V_S$) that get too close to eachother and a TCAS Resolution Advisory callout is announced. Would TCAS issue an RA to ...
9
votes
3answers
1k views

Is Auto Pilot capable of performing TCAS resolution advisory?

I just watched a near mid-air collision video clip on Youtube. When AP is on and TCAS gives resolution advisory ("climb climb" or "descend descend"), does AP automatically perform the advisory if the ...
8
votes
3answers
3k views

Can a drone be seen on TCAS?

On condition that the pilot reports to ATC, an aircraft's TCAS sees a drone in the vicinity. How can the pilot be sure that it was a drone on TCAS? What kind of symbol is shown on TCAS that can be ...
8
votes
1answer
596 views

What is the correct procedure to deal with a TCAS RA during intercept?

What is the correct procedure to follow if someone is intercepting you (or you are the F-16 driver intercepting someone else, for that matter) and you (or they, if you're the interceptor) get a TCAS ...
8
votes
1answer
704 views

Can TCAS be used to confirm “traffic in sight”?

If a pilot is asked to confirm traffic in sight, but they have hard time locating the traffic visually, however, they can see it on the TCAS display. Can they confirm they have the traffic in sight ...
8
votes
2answers
561 views

Why does TCAS not issue turning commands as Resolution Advisory?

The TCAS (Traffic Collision Avoidance System) is capable of issuing RA (Resolution Advisory) when a mid-air collision is imminent by telling the pilots to "climb", "descend", "increase climb" etc. ...
8
votes
1answer
484 views

What is the climb/descent rate that triggers the TCAS up/down arrow?

If Aircraft One is maintaining a low rate of climb/ descent, is there a minimum descent or climb rate threshold below which the up/down arrow will not show up on the TCAS of the Aircraft Two? I have ...
7
votes
2answers
2k views

Which FAA regulations require compliance with TCAS II Resolution Advisories?

I've always heard that complying with a TCAS II Resolution Advisory is a required action for pilots qualified and operating an equipped aircraft. I am not familiar with the regulatory basis for this, ...
6
votes
2answers
1k views

What's going on in this “confusing” TCAS Resolution Advisory video clip?

There's a clip on YouTube from a pilot of a 747-200 whose TCAS system issues a "confusing" RA: What exactly is happening here? For those who can't watch the video ...
5
votes
2answers
372 views

Does the RA (resolution Advisory) from TCAS II take into account the stall margin required?

A resolution advisory from TCAS indicates the vertical speed per minute that you must use to avoid conflict with the other traffic. Does this vertical speed given by the RA take into account the stall ...
5
votes
1answer
600 views

How frequent are TCAS resolution events?

The question is a little open, but I'm wondering how many TCAS resolutions (i.e. the serious type) occur every week or month over sizeable region like the United States or Europe.
4
votes
2answers
1k views

On an ADS-B In display, do the pilots see the squawk code or call sign for other aircraft?

If I understand correctly, with a ADS-B In equipment or TCAS equipment on board, the pilots could see the surrounding traffic with its assigned squawk code like "4653", is that right? But could the ...
4
votes
3answers
420 views

What is the need for TCAS?

Isn't it the job of the air traffic controller to assign altitudes and make sure airplanes do not collide in mid-air? Is having TCAS mandated or optional? If it is a mandate, then is there a mechanism ...
4
votes
1answer
293 views

What is the rationale of a weight/passenger value for the ICAO TCAS requirement?

What is the rationale for the figures 5,700 Kg and 19 passengers? Excerpt from TCAS's Wikipedia entry page: It is a type of ...
3
votes
1answer
898 views

Can you have TCAS RA if your other traffic only have TCAS TA?

If you fly and have a TCAS TA, it announce "TRAFFIC, TRAFFIC!" However, the other traffic executed a TCAS RA and did the "UNKNOWN" manouvre. Is it possible? As what i remember, it does takes two ...
3
votes
1answer
437 views

Can a TCAS be alerted when the intruder aircraft has a transponder in stand-by mode?

Can a TCAS give a TAs (traffic advisories) if the intruder aircraft has a transponder in stand-by mode?
3
votes
1answer
521 views

What action should the pilot take when a TCAS RA (Resolution Advisory) provides opposite guidance to ATC instructions?

If a TCAS Resolution Advisory (RA) specifies a "Climb," but in response to the same potential traffic threat, ATC issues instructions to "Descend" what course of action should the pilot/crew take?
3
votes
1answer
123 views

How could I match the surrounding traffics displayed with their radio communication

If I have a traffic display I could see the traffics in proximity of my aircraft and meanwhile I could listen to their voice communication. So how could I match the traffic shown in the display with ...
2
votes
2answers
244 views

Why are both ATC and TCAS tasked to prevent collisions although TCAS takes precedence anyway?

« The primary purpose of ATC worldwide is to prevent collisions [...] Many aircraft also have collision avoidance systems, which provide additional safety by warning pilots when other aircraft get ...
2
votes
3answers
505 views

Where could I find a MATLAB implementation of TCAS algorithms?

Where could I find a MATLAB implementation of TCAS algorithms and simulation? My research work deals with collision avoidance of a multi-UAV scenario in a small airspace.
2
votes
1answer
141 views

Why does setting the Legacy 600's transponder to standby mode also deactivate its TCAS?

In 2006, a 737 operating as Gol Transportes Aéreos Flight 1907 crashed following a collision with a Legacy 600 business jet; the Legacy's transponder proved to have been in standby mode1 at the time ...
2
votes
1answer
295 views

Could TCAS be overwhelmed by multiple conflicting traffic and “give up”?

I understand that TCAS can handle several "targets" simultaneously. However, I'm interested in the (highly hypothetical) scenario where TCAS would need to deal with multiple conflicts in a dense ...
2
votes
1answer
809 views

Do aircraft have radar or other forms of traffic sensing?

Quicky question. Do modern commercial aircraft include radar to detect traffic in their vicinity or perhaps have some mechanism to receive transponder signals. I know they have forward facing ...
2
votes
1answer
592 views

Can TCAS give an RA for one aircraft and a TA for another?

I am an air traffic controller and I had the following situation. Traffic maintaining FL360 and below him traffic at FL350 requesting FL370. Once they crossed each other I gave clearance to climb ...
2
votes
1answer
149 views

TCAS II - bottom omni-directional antenna

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 ...
2
votes
0answers
61 views

Is a TCAS capable of handling three (or more) planes on “crash course”? [duplicate]

I asked myself if the TCAS is capable to handle, the very unlikely situation, that three (or more) planes are simultaneously on "crash course" (Sorry, got no other word for it). If not, how would ...
1
vote
2answers
246 views

Could TCAS be used as a backup source for position, attitude or air data?

Given the number of incidents related to freezing pitot tubes, is there any current/planned implementation to infer aircraft position/speed/attitude/bearing based on TCAS data as a last resort data ...
1
vote
1answer
206 views

How is the TCAS negotation information encoded?

As I understand, according to this FAA booklet on TCAS, transponders will engage in cycles of interrogations and responses to establish if a collision may occur. The next step is for both TCAS ...
1
vote
1answer
337 views

How much time do pilots have to execute a TCAS Resolution Advisory?

The Wikipedia entry for TCAS (Traffic collision avoidance system) states for resolution advisories (RA): "When an RA [Resolution Advisory] is issued, pilots are expected to respond immediately to ...
1
vote
1answer
537 views

Does TCAS II equipment satisfy the required ADS-B installation?

The title says it all. If TCAS II is installed and functioning, does it satisfy the ADS-B OUT mandates?
0
votes
2answers
158 views

If all aircraft were TCAS-equipped, how would this change ATC routines?

« The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of air traffic, and provide information and other support for pilots. » (source) If all aircraft ...
0
votes
1answer
100 views

TCAS II manoeuvres? [duplicate]

What manoeuvres does the TCAS II advise the pilot to make? Is it RA or TA ?
-2
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1answer
80 views

Can a TCAS or Marker beacon antenna be installed inside a radome? [closed]

I was wondering how sensitive these systems are. We are planning a modification which will involve either moving these antennas or leaving them in place under a radome (the radome is designed for x-...
-6
votes
1answer
286 views

Incident over the pacific [closed]

I read this from the new CNN.com: Two planes nearly collide over Pacific. The death toll would amount more than the Tenerife's one if things went actually wrong. Kevin Townsend tells more in his ...