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Preliminary report


Preliminary report published: 29 June 2018

Sequence of events

On 24 November 2017, at about 1200 Western Standard Time,[1] the crew of an Airbus A320 aircraft, registered PK-AZE and operated by AirAsia Indonesia, was being prepared to depart on a scheduled passenger service from Perth Airport, Western Australia for Denpasar (Bali) Airport, Indonesia. The captain was designated as the pilot monitoring and the first officer (FO) was designated as the pilot flying.[2]

While the captain was conducting the pre-flight walk around, the FO entered the flight plan into the flight management guidance computer (FMGC). Believing that they would be using runway 03 for take-off, as they had recently landed on this runway, he entered this into the FMGC. He then listened to the automatic terminal information service,[3] which indicated the runway-in-use was runway 21. When the captain returned to the fight deck, the FO completed the pre-flight and departures briefing using runway 03. At 1201, the crew received their clearance from air traffic control (ATC) to depart for Denpasar using the AVNEX TWO standard instrument departure (SID)[4] and to climb to 5,000 ft using the SID (Figure 1). At 1213, the crew commenced taxiing. The crew also received ATC clearances to taxi to, and line-up on runway 21, which was read back correctly by the crew.

Figure 1: AVNEX TWO standard instrument departure

Figure 1: AVNEX TWO standard instrument departure. Source: Naviga, modified by the ATSB

Source: Naviga, modified by the ATSB

At 1220, the aircraft took off from runway 21. Shortly after take-off, the aircraft was turned left at 260 ft above mean sea level (AMSL) (Figure 2), which was contrary to the SID procedure and below the minimum safe altitude stipulated by the operator. The runway 21 SID required a right turn at or above 2,500 ft at waypoint[5] NAVEY (Figure 1) and the operator stipulated that turns should not be commenced below 400 ft above ground level.

After observing the aircraft turning left on radar, ATC re-cleared the crew onto an assigned radar heading. ATC later confirmed with the crew they were issued with the AVNEX TWO SID and asked if operations were normal. The crew reported operations normal and the aircraft was turned to intercept the flight planned route and continued to Denpasar without further incident.

Figure 2: Flight path of PK-AZE (in white) showing the left turn (waypoints highlighted in blue)

Figure 2: Flight path of PK-AZE (in white) showing the left turn (waypoints highlighted in blue). Source: Google earth and Air Asia Indonesia, modified by the ATSB

Source: Google earth and Air Asia Indonesia, modified by the ATSB

Recorded data

The aircraft’s flight data recorder was downloaded and a copy was provided to the ATSB. A review of that recording found:

  • the waypoint MIDLA was the first selected waypoint in the flight management guidance computer, which was the first waypoint on the AVNEX TWO SID for runway 03 (Figure 1)
  • when manually flown, the aircraft was turned left at 260 ft AMSL
  • after multiple heading changes were made by the crew, waypoint SWANN was selected at 8,104 ft, which was the second waypoint on the runway 21 AVNEX TWO SID.

Ongoing investigation

The investigation is continuing and will consider the following:

  • operator pre-flight procedures and checklists
  • crew training and qualifications
  • aircraft systems.

The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this preliminary report. As such, no analysis or findings are included in this update.



  1. Western Standard Time is Coordinated Universal Time (UTC) + 8 hours.
  2. Pilot flying (PF) and pilot monitoring (PM): procedurally assigned roles with specifically assigned duties at specific stages of a flight. The PF does most of the flying, except in defined circumstances; such as planning for descent, approach and landing. The PM carries out support duties and monitors the PF’s actions and the aircraft’s flight path.
  3. Automatic terminal information service (ATIS): The provision of current, routine information to arriving and departing aircraft by means of continuous and repetitive broadcasts during the hours when the unit responsible for the service is in operation.
  4. Standard instrument departure: A designated instrument flight rules departure route linking the aerodrome or a specified runway of the aerodrome with a specified point, normally on a designated air traffic services route, at which the en route phase of a flight commences.
  5. Waypoint: A specified geographical location used to define an area navigation route or the flight path of an aircraft employing area navigation.
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