How frequent are TCAS resolution events?

  • How frequent are TCAS resolution events? Manfred

    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.

  • I found a very interesting paper from 2007 that analyzed TCAS performance. They analyzed recorded data to come up with 1 RA per 116 flight hours.

    Over this time period, monitoring took place for approximately 190 days, and roughly 200,000 Mode S flight hours were observed within the sensor’s 60 nmi coverage area. We observed a total of 1725 RA events, corresponding to an average of 9 RAs per day, or approximately one RA every 116 flight hours.

    They explain that the data was taken in the Boston area, so the high amount of traffic contributes to the high number of RAs.

    This thread on suggest differently, at least in the sense that for those pilots it is a matter of a few over years, depending on where they typically fly.

Related questions and answers
  • 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.

  • Referring to the automated callouts and sounds made by the fwc, tcas, gpws, pws, etc. — are these available to download in one repository at all? For any aircraft, Airbus or Boeing. Understandably, these may not be freely available, but I'm curious otherwise too (e.g. the likes of Air Crash Investigation must do this).

  • 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. There is a reporting requirement in NTSB 830 which states (bold added by me): 49 CFR 830.5 - Immediate notification The operator of any civil aircraft, or any public aircraft not operated... airplanes get within a certain distance from each other? When a report is required, how do we report it and what information is required? Is there a form that needs to be filled out?

  • Air Force One is obviously a big deal. We close terminals and implement other seemingly crazy safeguards against terrorist attacks while the president is en-route to an airport. How does ATC protect the president whilst in the air? I have heard of TFRs for "VIP in the area" reasons — is that for AF1? I am guessing that the aircraft identification is blocked, but wouldn't they still need to have the transponder on for TCAS? Specifically, the Wikipedia page on Air Force One has the following quote: Air traffic controllers gave Air Force One an ominous warning that a passenger

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  • How does TCAS work? Danny Beckett

    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? Also, can you give an overview of the various types of TCAS, and how planes agree a resolution?

  • Provided an aircraft with a fly-by-wire system, there are basically two possible choices when it comes deciding how to let the pilots interface with it: rate control / attitude hold: a deflection of the stick will command a certain rate, releasing it will make the system maintain the current attitude. See the Airbus Normal control law. direct control: a deflection of the yoke will directly... how Airbus and Boeing made their design decisions, but rather see if there has been performed a study on what interface is preferred by pilots, eventually differentiating among private/commercial pilots

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  • Primary target: An aircraft not reporting mode-C, the only thing the controller has is the return on the radar. When a controller reports a primary target as traffic to other aircraft, the controller does not have the altitude of the target. Given this, I conclude that ATC radar does not have the altitude (angle-up) to the target, and only provides azimuth. So then without the altitude, how does the radar-system know where to put the target laterally on the screen? Example, a radar picks up a target that is 10 miles from the station. If the target is 0 AGL, the proper position would be 10

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