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Atc recording for vienna to Dublin (potential incident)

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  • 18-11-2018 9:41am
    #1
    jon1981
    Registered Users Posts: 4,359 ✭✭✭


    Hi,

    I was on an aer lingus flight (ei0661) from Vienna to Dublin on Friday the 16th November. We were approaching Dublin airport, about 15 mins out when suddenly the plane descended rapidly and then climbed rapidly. It really shook alot of people. A guy beside me freaked out alittle. I fly alot with work and i never witnessed this, it wasn't just turbulence.

    I'm wondering where i could find recordings of this route to satisfy my curiosity?


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    #2
    windowspotter
    Registered Users Posts: 165 ✭✭windowspotter


    You can listen back here

    https://www.liveatc.net/archive.php

    Let us know what you find


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    #3
    rio1
    Registered Users Posts: 92 ✭✭rio1


    Does not look unusual on Flightradar24.Did you look there?


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    #4
    nim1bdeh38l2cw
    Closed Accounts Posts: 689 ✭✭✭nim1bdeh38l2cw


    Nothing unusual about that, I was on a flight into CDG before and were about to touch down, could see the runway etc and the same happened. Previous plane to land hadn't cleared the runway yet


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    #5
    rio1
    Registered Users Posts: 92 ✭✭rio1


    Izaiah Enough Windshield wrote: »
    Nothing unusual about that, I was on a flight into CDG before and were about to touch down, could see the runway etc and the same happened. Previous plane to land hadn't cleared the runway yet

    That’s different, what you are describing is a go around. That didn’t happen on the Vienna Dublin flight on the 16th


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    #6
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    Could it have been some unexpected local weather anomaly that caused the sudden descent and then the plane automation kicking in to return to previous course?? Not sure what the granularity of data is on fr24, but if it all happened in a few seconds then it might not have been recorded maybe...


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    #7
    orionm_73
    Registered Users Posts: 357 ✭✭orionm_73


    Could it have been a reaction to a TCAS warning?


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    #8
    Luke-m
    Registered Users Posts: 54 ✭✭Luke-m


    I looked at fr24 and you can see when the plane is descending to 12100 feet it suddenly climbs to 12420. No idea why of course. Someone else might know


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    #9
    rio1
    Registered Users Posts: 92 ✭✭rio1


    Saw where you mean. It’s minor, but the engine would have had to power up so you would have felt it a bit alright.


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    #10
    rio1
    Registered Users Posts: 92 ✭✭rio1


    Are there ever reports of incidents with drones around there?


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    #11
    Lustrum
    Registered Users Posts: 751 ✭✭✭Lustrum


    jon1981 wrote: »
    Hi,

    I was on an aer lingus flight (ei0661) from Vienna to Dublin on Friday the 16th November. We were approaching Dublin airport, about 15 mins out when suddenly the plane descended rapidly and then climbed rapidly. It really shook alot of people. A guy beside me freaked out alittle. I fly alot with work and i never witnessed this, it wasn't just turbulence.

    I'm wondering where i could find recordings of this route to satisfy my curiosity?

    TCAS RA with an aircraft climbing from below. I suspect what felt like a rapid descent was more a change from the rate of descent to a rate of climb


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    #12
    EchoIndia
    Registered Users Posts: 2,950 ✭✭✭EchoIndia


    SAS70A (A320 from DUB-ARN) was more than 2,000 feet below EIN661 when it passed slightly in front, according to the FR24 playback.


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    #13
    rio1
    Registered Users Posts: 92 ✭✭rio1


    EchoIndia wrote: »
    SAS70A (A320 from DUB-ARN) was more than 2,000 feet below EIN661 when it passed slightly in front, according to the FR24 playback.


    That’s really interesting. What’s the allowed distance between aircraft over Dublin before a TCAS TA?


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    #14
    EchoIndia
    Registered Users Posts: 2,950 ✭✭✭EchoIndia


    Minimum legal separation is 1,000 feet.


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    #15
    faoiarvok
    Registered Users Posts: 644 ✭✭✭faoiarvok


    rio1 wrote: »
    That’s really interesting. What’s the allowed distance between aircraft over Dublin before a TCAS TA?

    It’s not based on distance, but time according to the calculated closing rate.

    Traffic Advisories are issued up to 48 seconds from calculated Closest Point of Approach (shorter at lower altitudes), and trigger no action other than to scan for traffic and anticipate an RA.

    Resolution Advisories are issued up to 35 seconds from CPA, and require the crew to follow the RA.

    https://www.skybrary.aero/index.php/Airborne_Collision_Avoidance_System_(ACAS)


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    #16
    Bsal
    Registered Users Posts: 1,772 ✭✭✭Bsal


    The wind was southerly at the time the aircraft was on approach, I'm going to guess it was turbulence from mountain wave activity from the Wicklow mountains.


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    #17
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    faoiarvok wrote: »
    It’s not based on distance, but time according to the calculated closing rate.

    Traffic Advisories are issued up to 48 seconds from calculated Closest Point of Approach (shorter at lower altitudes), and trigger no action other than to scan for traffic and anticipate an RA.

    Resolution Advisories are issued up to 35 seconds from CPA, and require the crew to follow the RA.

    https://www.skybrary.aero/index.php/Airborne_Collision_Avoidance_System_(ACAS)
    So, if TCAS reports a TA, does that indicate an ATC boo-boo occurred? I suspect the answer is "not necessarily" as the climbing aircraft could be due to level off within the 48 second window ...


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    #18
    PukkaStukka
    Registered Users Posts: 2,164 ✭✭✭PukkaStukka


    EchoIndia wrote: »
    Minimum legal separation is 1,000 feet.
    Is there a minimum lateral separation as well?


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    #19
    faoiarvok
    Registered Users Posts: 644 ✭✭✭faoiarvok


    plodder wrote: »
    So, if TCAS reports a TA, does that indicate an ATC boo-boo occurred? I suspect the answer is "not necessarily" as the climbing aircraft could be due to level off within the 48 second window ...

    Exactly. An RA could even be issued without minimum separation being infringed if the aircraft are climbing and descending quickly.


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    #20
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    faoiarvok wrote: »
    Exactly. An RA could even be issued without minimum separation being infringed if the aircraft are climbing and descending quickly.
    If that's what happened, then it's a very impressive real-life test of the system and it's good to see that it works.


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    #21
    jon1981
    Registered Users Posts: 4,359 ✭✭✭jon1981


    Thanks everyone for satisfying my curiosity on this. Perhaps it was a sudden ascent as oppose to descent, your senses are alittle all over the place when you have no point of reference to look at (aisle seated, cloudy outside...etc.).

    Btw was that TCAS RA mentioned on one of the audio recordings of the ATC channels?


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    #22
    Lustrum
    Registered Users Posts: 751 ✭✭✭Lustrum


    If you can listen back, you'll probably head the crew advise ATC "TCAS RA" to let them know they're deviating from their current trajectory, and once clear either telling them that they're returning to where they were or asking what ATC would like them to do.

    A TA or RA doesn't necessarily mean anyone has made a mistake, as said earlier they're a result of closure rates that the computer predicts will result in an infringement of the converging paths remain the same at the same closure rate. Flying into and out of LCY you'd get them all the time as the airspace is so congested, but crews are all trained to deal with both TAs and RAs (any type I've flown they've been memory items) and once the closure rate is either slowed, or one of the aircraft turns etc. that's it, end of not-much-drama-at-all. However, when you're down the back and don't know that I can see how it might raise your eyebrows a bit.


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    #23
    View Profile
    Registered Users Posts: 1,133 ✭✭✭View Profile


    A RA is a fairly benign manoeuvre and shouldn't really be noticed by passengers, if handled calmly by the crew.


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    #24
    EchoIndia
    Registered Users Posts: 2,950 ✭✭✭EchoIndia


    Lustrum wrote: »
    If you can listen back, you'll probably head the crew advise ATC "TCAS RA" to let them know they're deviating from their current trajectory, and once clear either telling them that they're returning to where they were or asking what ATC would like them to do.

    The LiveATC recording is for a scanner covering multiple Dublin frequencies, including Tower and Ground Movements (which dominate). I listened back and didn't hear anything TCAS-related for the relevant time period.


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    #25
    Lustrum
    Registered Users Posts: 751 ✭✭✭Lustrum


    EchoIndia wrote: »
    The LiveATC recording is for a scanner covering multiple Dublin frequencies, including Tower and Ground Movements (which dominate). I listened back and didn't hear anything TCAS-related for the relevant time period.

    If they were up about FL120 they probably would have been in contact with Dublin North still, probably still a bit high for Approach even.


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    #26
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    View Profile wrote: »
    A RA is a fairly benign manoeuvre and shouldn't really be noticed by passengers, if handled calmly by the crew.
    Surely, it depends? If you are descending rapidly and the RA says to climb ...


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    #27
    Brennus335
    Registered Users Posts: 168 ✭✭Brennus335


    plodder wrote: »
    Surely, it depends? If you are descending rapidly and the RA says to climb ...

    You have 5 seconds to respond to an initial RA, and 2.5 seconds to respond to any subsequent reversal. It is also predicated on being a 1G maneuver, so if flown correctly, shouldn't really be noticed by anyone down the back.

    As stated earlier, the vast majority of RA's are caused by high rates of climb or descent when approaching a cleared level. Eg, climbing to FL280 and approaching with 3000fpm with an opposite direction aircraft maintaining FL290, will most likely result in an RA. The TCAS system doesn't know you're going to be levelling off at 280, it only works on time to predicted point of closest approach.


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    #28
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    Brennus335 wrote: »
    You have 5 seconds to respond to an initial RA, and 2.5 seconds to respond to any subsequent reversal. It is also predicated on being a 1G maneuver, so if flown correctly, shouldn't really be noticed by anyone down the back.
    Do you mean "have caused alarm" because I certainly would have noticed this maneuver? Also, maybe a difference in use of terminology but level flight or even sitting on the ground is 1G is it not? Which must mean that leveling off any descent must be > 1G?
    As stated earlier, the vast majority of RA's are caused by high rates of climb or descent when approaching a cleared level. Eg, climbing to FL280 and approaching with 3000fpm with an opposite direction aircraft maintaining FL290, will most likely result in an RA. The TCAS system doesn't know you're going to be levelling off at 280, it only works on time to predicted point of closest approach.


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    #29
    View Profile
    Registered Users Posts: 1,133 ✭✭✭View Profile


    TCAS generally commands a fairly gentle manoeuvre to resolve the potential conflict. A gentle climb or descent is all is required to avoid the opposite traffic. It's not like some 7g top gun manoeuvre.

    I'd be surprised if any pax could differentiate between a normal climb/descent and a TCAS generated one.

    Any RA I've had is uneventful and undramatic.


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    #30
    Brennus335
    Registered Users Posts: 168 ✭✭Brennus335


    plodder wrote: »
    Do you mean "have caused alarm" because I certainly would have noticed this maneuver? Also, maybe a difference in use of terminology but level flight or even sitting on the ground is 1G is it not? Which must mean that leveling off any descent must be > 1G?

    The exact figures are 1.25g for initiating a climb, descent, or level off, and 1.33g for a reversal. That's similar to any climb, descent or level off during routine operations.
    If an RA is properly flown, pax shouldn't be able to tell the difference from anyother normal maneuver.

    As stated above, these aren't Top Gun style combat maneuvres.

    I teach them in the sim all the time. In fact I must've witnessed about 10 last night, ranging from simple "Monitor Vertical Speed", to full "descend, descend... Climb, climb now" reversals.


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    #31
    plodder
    Registered Users Posts: 7,221 ✭✭✭plodder


    Brennus335 wrote: »
    The exact figures are 1.25g for initiating a climb, descent, or level off, and 1.33g for a reversal. That's similar to any climb, descent or level off during routine operations.
    If an RA is properly flown, pax shouldn't be able to tell the difference from anyother normal maneuver.

    As stated above, these aren't Top Gun style combat maneuvres.

    I teach them in the sim all the time. In fact I must've witnessed about 10 last night, ranging from simple "Monitor Vertical Speed", to full "descend, descend... Climb, climb now" reversals.
    I think it's just when descending to land, you're not expecting any kind of climbing maneuver. So, as a passenger that is what you notice, rather than the rate of ascent/descent.


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