TCAS

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    Oslo: October 31, 2013, Near Miss

    We wrote about two Norwegian Air Shuttle planes that suffered a near miss when two planes followed the same instruction from ATC. The Accident Investigation Board Norway (AIBN) report on the event is below.

    Report (Translation)
    Description
    The 31 October 2012, two airliners from English too close together under a simultaneous missed approach (NAX741) and departure (NAX740) at Oslo Airport. There was strong tailwind on final. The AIBN believes that the flight crew on NAX741 had unrealistic expectations of the ability to be stabilized later in 1000 ft above the airport elevation. The decision to initiate the missed approach was taken at a late stage. Expectations of final-controller and tower controller that the speed of the landing would be reduced sufficiently during the approach, was not met. The missed approach for NAX741 came into conflict with the simultaneous departure of NAX740.

    Visibility conditions were such that the tower controller could not maintain visual separation between aircraft. Planes were for each other and both were rising. Tower air traffic controller instructed NAX741 to swing west. A mixture of callsign originated and led to NAX740 initiated clearance given to NAX741. The minimum horizontal distance between the aircraft was about. 0.2 NM (370 m) while the vertical height difference was 500 ft (152 m). AIBN considers that there was real danger of collision in the incident. When the situation first arose, prevented the situation awareness and good reviews from the flight crew and tower controller further escalation of the conflict.

    AIBN considers that established and practiced procedures will help to ensure that situations are recognized and averted before they become critical. Data from the cockpit voice recorder (Cockpit Voice Recorder CVR) was not secured. CVR data is important to understand the sequence of events, and AIBN therefore it is unfortunate that CVR data is not guaranteed. AIBN no new safety recommendation in this report, but refers to a previously issued safety recommendation (SL no 2012/06T) not closed.

    Type of report: Full report
    Location: Oslo Airport Gardermoen ENGM
    Event Date: 31/10/2012
    ICAO Location indicator: ENGM
    Aircraft: Boeing 737-600/700/800 / Boeing 737-600/700/800
    Operator: Norwegian Air Shuttle / Norwegian Air Shuttle
    Reg notice: LN-DYC / LN-NOM
    Flight conditions: IMC
    County: Akershus
    Type of event: Serious incident
    Type of flight: Commercial, scheduled / Commercial, scheduled
    Category Aviation: Tung, aircraft (> 10 000kg) / Tung, aircraft (> 10 000kg)
    Flykategori: Land plane, multi-engine, turbofan / turbojet
    FIR / AOR: ENOS (Oslo ATCC)

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    Oslo: Near Miss

    On Oct 31, 2013, a Norwegian Boeing 737-800#LN-DYC en route from Trondheim to Oslo with 130 passengers and 6 crew, was descending towards Oslo and was switched to a different runway. A second Norwegian Boeing 737-800 #LN-NOM en route from Oslo to Trondheim took off. Instructions from ATC became confused, and both planes followed a single instruction, bringing them into proximity.

    Flight 741, which was landing, was below Flight 740. Flight 740 got a TCAS (Traffic collision avoidance system) warning and diverged. Accident Investigation Board Norway noted the minimum separation between the two aircraft was down to 0.2nm lateral at 500 feet vertical.

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    Comoros: Crash Averted


    Click to view full size photo at Airliners.net
    Contact photographer Sam Chui

    What: Yemenia Airbus A330-200 en route from Djibouti to Moroni Comoros
    Air Austral Boeing 777-200 en route from Lyon to Saint Denis
    Where: Moroni, Comoros
    When: Aug 24 2010
    Who: 350 passengers aboard the Boeing
    Why: Both flights were in the air, the Airbus flying at a higher altitude. The Airbus unexpectedly descended without ATC clearance.

    The Boeing received a TCAS resolution advisory, to which they immediately responded, averting a collision.

    George’s Point of View

    I am reminded of the sad and tragic events of June 30, 2009, when Air Yemenia failed to make a safe landing and killed everyone aboard but Bahia Bakari.

    Confusion again reigns in Moroni, Comoros airspace. I am grateful for the successful TCAS resolution/response. Apologies if the date is in error, as we find different dates published for this averted catastrophe.
    http://lexpress.mu/story/14905-collision-evitee-de-justesse-en-plein-vol-entre-un-appareil-d-air-austral-et-un-vol-d-air-yemenia.html
    http://www.zinfos974.com/Deux-avions-d-Air-Austral-et-de-la-Yemenia-manquent-de-se-percuter_a20567.html

    http://info.sfr.re/faits-divers/articles/-Deux-avions-d-Air-Austraet-de-la-Yemenia-manquent-de-se-percuter,146146/

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    LA: Near Collision


    Click to view full size photo at Airliners.net
    Contact photographer Peter Nowacki

    What: Westjet Airlines Boeing 737-700 en route from Vancouver to Los Angeles
    Where: Los Angeles
    When: Jul 24th 2010
    Who: 115 aboard
    Why: After an averted landing, the pilot was positioning to circle for a second approach (revectoring) and the flight crew received a TCAS warning to climb.

    The Cessna 182 was on its same altitude. The Boeing climbed and successfully achieved lateral separation.

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    Traffic: Congonhas


    Click to view full size photo at Airliners.net
    Contact photographer Lorenzo Costa

    What: TAM Linhas Aereas Airbus A320-200 en route from Brasilia to Sao Paulo
    Where: Sao Paulo
    When: June 24 2010
    Who: 171 people on board
    Why: On approach to Congonhas, the pilot was notified of a flight leaving Congonhas, and had to maneuver according to ATC direction, then continued on to land at Congonhas. Meanwhile, one of the flight attendants landed on a passenger. No one was injured in either event.

    The plane causing the evasive maneuver was an Embraer EMB-110 Bandeirante.