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ASN Wikibase Occurrence # 238769
Last updated: 28 July 2020
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Type:Silhouette image of generic B77W model; specific model in this crash may look slightly different
Boeing 777-322ER
Owner/operator:United Airlines
Registration: N2333U
C/n / msn: 62644/1466
Fatalities:Fatalities: 0 / Occupants: 162
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:2 km north Sydney Airport, NSW -   Australia
Phase: Initial climb
Nature:Passenger - Scheduled
Departure airport:Sydney-Kingsford Smith International Airport, NSW (SYD/YSSY)
Destination airport:San Francisco International Airport, CA (SFO/KSFO)
Investigating agency: ATSB
On the early afternoon of 22 January 2020, a Boeing 777-300ER, registered N2333U, was being operated by United Airlines as regular flight UA870 from Sydney, Australia to San Francisco, United States.
At about the same time, an ATR 72-600, registered VH-FVQ, was being operated by Virgin Australia as regular flight VOZ1153 from Sydney to Tamworth, Australia.
The weather was fine, with excellent visibility, no cloud below 10,000 ft and a light wind from the northwest.
The flight crew for flight UA870 consisted of a captain and three first officers. The captain was the pilot flying (PF) and one of the first officers was the pilot monitoring (PM). The remaining first officers occupied the two observers’ seats positioned directly behind the PF and PM on the flight deck.
Sydney air traffic control attempt to facilitate expeditious departures to all aircraft, particularly aircraft transiting over extended distances (oceanic crossings). This regularly involves a clearance via the SYDNEY ONE RADAR (SYD1) standard instrument departure (SID). The PF had operated from Sydney Airport on a number of other occasions. While preparing for departure at the gate, after receiving the ATIS, but prior to receiving their pre-departure clearance, the PF configured the flight management computer (FMC) for the SYD1 based on an expectation from prior experience.
At about 13:30 local time, Sydney clearance delivery (SCD) air traffic control (ATC) provided a different pre-departure clearance via VHF radio: "United eight seventy, delivery, cleared to San Francisco via DIPSO, flight planned route, runway three four left (34L), Richmond five departure, radar transition, climb via SID to five thousand ...".
The PM provided a truncated read back of the clearance to ATC, inadvertently not repeating the radar transition component.
At the same time as the UA870 crew were preparing for their departure, VOZ1153 was cleared to depart via the SYD1 radar SID via runway 34R. This procedure required the ATR 72 to maintain a heading of 350º after take-off, until directed otherwise by ATC.
The UA870 crew reviewed the RICHMOND FIVE (RIC5) SID chart. That chart included two distinct caution notes about the initial climb. The more detailed caution stated: "Parallel runway operations - DO NOT TURN RIGHT. Track 335°. At 1500 [ft] turn LEFT, track direct RIC NDB [Richmond], then follow transition instruction. "
The PF then re-programmed the FMC, replacing the SYD1 procedure with the RIC5. At this point, the PF reported being unsure regarding the coding specific to the two transition options (radar or Richmond) presented by the FMC.
The radar transition option in the FMC included a deliberate discontinuity (gap) in the waypoint sequence (coding). The discontinuity represented the point where air traffic control would provide radar vectors to facilitate a re-join to the oceanic track (to San Francisco) after the aircraft passed 12 NM from Sydney.
The PF then closed (removed) the discontinuity. In effect, the PF had removed the preprogrammed radar transition procedure, which meant that after the 1,500 ft left turn, the next waypoint on the route was DIPSO, not 12 NM Sydney. The PF recalled communicating removing the discontinuity to the PM, but it was not acknowledged by the PM. The PM did not recall hearing about the coding change.
Later in the pre-departure preparation, the PM reported verifying the new departure in the FMC using the summary route (RTE) page. However, the PM did not review it using the more detailed LEGS page.
While taxiing to the runway for take-off, the PM recalled that when completing the departure review with the PF, they noted the FMC RTE page read: Runway 34L, Richmond Five (RIC5), no transition
At 14:21:41 the tower controller for runway 34R cleared VOZ1153 for take-off, and 42 seconds later, the tower controller for runway 34L cleared UA870 for take-off.
At 14:22:29, VOZ1153 departed runway 34R. About 35 seconds later, as VOZ1153 was climbing through 1,500 ft, UA870 departed runway 34L. (The runway 34L threshold is about 1,000 m north [ahead] of the runway 34R threshold)
At about 14:24:06, climbing through 1,417 ft, the UA870 crew were instructed to contact Sydney departures control.
At 14:24:33, as UA870 was climbing through 2,120 ft, the Sydney departures controller detected that the aircraft was turning right and instructed the crew to immediately turn left, to a heading of 270°. The flight crew had also identified the incorrect turn to the right. The departures controller then issued a separate interventional instruction to VOZ1153 to turn right immediately, to a heading of 090°.
On receiving their instruction, the two UA870 pilots in the observers’ seats identified the traffic (VOZ1153) visually (right-hand observer) and via the traffic alert and collision avoidance system (TCAS) display (left-hand observer).
Recorded flight data showed that the UA870 autopilot was disengaged about 3 seconds after the interventional instruction to UA870 was received, at an altitude of 2,160 ft. Due to the momentum of the 777, the aircraft continued turning right through a further 5 degrees to heading 018º, prior to the PF manually reversing the turn back to the left. The minimum distance between the two aircraft was 1.0 NM laterally and 200 ft vertically. Both aircraft continued flight to their respective destinations without further incident.

Contributing factors
• The pilot flying incorrectly amended the flight management computer (FMC) for the cleared departure.
• The amended FMC setup was probably not effectively communicated to the crew or effectively cross-checked by the pilot monitoring or relief pilots.
Other factors increasing risk
• The pilot monitoring did not complete a full readback of the radar transition component of the pre-departure clearance, nor did the Sydney clearance delivery controller insist on a full readback.



Accident investigation:
Investigating agency: ATSB
Status: Investigation completed
Duration: 6 months
Download report: Final report


Source: ATSB

Revision history:

28-Jul-2020 17:52 harro Added
28-Jul-2020 18:07 harro Updated [Departure airport, Accident report, ]

Corrections or additions? ... Edit this accident description