proximity

proximity (lack of separation)

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    About Close Calls

    After making note of the Oct 31 near miss in Oslo, I remembered this 100 foot close call of two Boeing 747’s over Scotland. This occurred in late June, when a Lufthansa pilot was climbing, and a British Airways flight were 24.3nm apart on converging courses. A STCA (Short Germ Conflict Alert)

    The Oslo near miss could have been prevented if the repetition protocol have been observed.

    The Scotland near miss had two planes
    (DLH418 Lufthansa Boeing 747-830, D-ABYC Frankfurt (FRA) – Washington Dulles International Airport (IAD))

    and

    (BAW87 British Airways Boeing 747-436, G-BNLM London-Heathrow (LHR) – Vancouver (YVR))

    on a collision course 100 feet Vertical/3.9 nm Horizontal and 1100 feet Vertical/2.8nm from impact. The study of the event concluded that actions of both the pilots and the controller contributed but that the pilots avoiding ATC instructions caused the proximity issue.

    The added pressure of reporting incidents such as these should help pilots and air traffic control to avoid similar events in the future. It will do so ONLY if adequate attention is paid to the mistakes, if alternative/better responses are deter mend, if the resulting studies are closely attended, and if protocol is adjusted to reduce the possibility of such problems re-occurring. On some level, the protocol worked, because these incidents were not collisions. However, they were closer than they should be. All I can say about this event is that it is a good thing that mistakes are reported.

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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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    Proximity Blamed on Tenerife South ATC

    On November 12, 2011, the Iberia Airbus A321 had been approaching Tenerife South airport at high speed just before it landed on the same runway that a Jet2 Boeing 757-200 was departing did so because of a premature take-off clearance to the 757.

    The 757 was airborne over the runway as the A321 touched down at an unexpectedly fast approach. Although the A321’s airspeed had decreased constantly through the descent, its ground speed was 210kt. Expected airspeed is in the 180-203kt range.

    The planes were separated by at least 4,100ft.

    The incident has been attributed to the tower controller’s “improper handling” of the take-off clearance to the 757.

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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.

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    SF: Close Call


    Click to view full size photo at Airliners.net
    Contact photographer Neil Guinea

    What: United Airlines Boeing 777-200 en route from San Francisco to Beijing
    Where: San Francisco
    When: Mar 27 2010
    Who: 251 passengers and 17 crew
    Why: After takeoff, the Boeing’s Traffic and Collision Avoidance System issued a traffic advisory, recognizing an Aeronca too close. From a lower altitude, the Boeing crew only saw a portion of Aeronca that was passing between 200-300 feet away. TCAS warned them to drop their altitude to increase separation. The Aeronca was directed to take a “hard left”