Indonesia AirAsia A320 at Perth on Nov 24th 2017, operational non-compliance

Last Update: June 2, 2020 / 17:18:42 GMT/Zulu time

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Incident Facts

Date of incident
Nov 24, 2017


Flight number

Aircraft Registration

Aircraft Type
Airbus A320

ICAO Type Designator

An Indonesia AirAsia Airbus A320-200, registration PK-AZE performing flight QZ-535 from Perth,WA (Australia) to Denpasar (Indonesia), was climbing out of Perth's runway 21 when the crew initiated a left turn at 300 feet AGL. ATC immediately intervened and instructed the crew to turn onto a southerly heading. The aircraft continued to Denpasar for a landing without further incident.

Australia's ATSB rated the occurrence an accident and opened an investigation. The ATSB reported the standard departure route required the aircraft to continue straight on runway heading until 5nm out, then turn right.

The ATSB sent notifications of an incident rather than accident to other air accident investigation bodies and subsequently also updated their own website to now show an incident rather than an accident (standing Dec 7th 2017).

On Jun 29th 2018 the ATSB released additional information stating the first officer was pilot flying, the captain pilot monitoring. The captain was performing the walk around when the first officer was programming the FMS and prepared the FMGC for a departure from runway 03 as they had landed on that runway. However, upon listening to ATIS it was indicated runway 21 was in use. The first officer completed the programming for runway 03. After the captain had returned to the cockpit the crew received their departure clearance from runway 21, were instructed to taxi to the holding point runway 21 and subsequently were cleared for takeoff from runway 21. After becoming airborne the aircraft began to turn left at 260 feet AGL which is contrary to the SID and assigned flight path requiring a right hand turn 5nm after the end of the runway or above 2500 feet MSL. The air traffic controller noticed the left turn and immediately set the aircraft onto a radar heading, which the crew complied with, the aircraft subsequently joined the intended departure route and continued to destination without further incident.

The ATSB downloaded the flight data recorder and found the first waypoint after departure was MIDLA, which is the first waypoint for the AVNEX TWO standard departure route from runway 03. The aircraft turned left at 260 feet AGL while being manually flown. After several heading changes waypoint SWANN became active at about 8000 feet which was the second waypoint of the AVNEX TWO SID runway 21.

On Jun 2nd 2020 the ATSB released their final report concluding the probable causes of the incident were:

Contributing factors

- Based on a recent landing, the first officer assumed runway 03 would be in use and programmed this runway for take-off into the flight management guidance system (FMGS) before listening to the automatic terminal information service (ATIS). Although the first officer copied runway 21 from the data recorded onto the flight plan, he did not notice this differed from what he had programmed into the FMGS and briefed the captain for a runway 03 takeoff.

- The captain did not obtain any independent information about the runway-in-use for pre-departure checks, including listening to the ATIS and reviewing data recorded on the flight plan, and likely relied on verbal information from the first officer.

- The incorrect programming of the FMGS was not detected before take-off despite numerous cues that the departure runway and flight path was different to what was briefed. Although the flight crew sensed there was something amiss with their pre-flight preparation, they continued without further checking.

- Shortly after take-off from runway 21, the aircraft was turned left at 223 ft above ground level. This was below the minimum allowable height of 400 ft stipulated by the operator, and well before and in the opposite direction to the cleared standard instrument departure.

Other factors that increased risk

- The flight crew did not communicate the nature of the problem to air traffic control and so did not effectively utilise air traffic control as an available resource. This resulted in the captain unnecessarily reprogramming the FMGS at a time when workload was already high.

The ATSB analysed:

Very shortly after take-off from runway 21 at Perth, Western Australia, the aircraft was turned at a low height in the opposite direction to their clearance and towards an escarpment. Air traffic control (ATC) assigned a series of headings to the flight crew to correct their path. During that time, the aircraft also turned through one of the assigned headings. An additional heading was issued by ATC to return the aircraft back to its planned track. The flight continued without further incident.

Although there were time delays for the flight crew’s sectors that day, there was insufficient evidence to indicate that this contributed to the development of the incident.


Based on their recent landing on runway 03, the first officer (FO), who was the pilot flying had the expectation that the take-off runway would remain the same, as experienced on previous occasions. Consequently, he entered runway 03 into the FMGS in preparation for the departure.

This was done prior to listening to the ATIS and obtaining the airfield data, which indicated that runway 21 was in-use. This was performed out-of-sequence, where the operator’s procedure required the airfield data to be obtained before programming the FMGS. While the FO commented in his interview that he would normally follow the procedure, on this occasion, he elected to program the FMGS first to make it ‘easier’.

Although the FO correctly noted the ATIS details for runway 21 on his paper flight plan, he did not detect that it was different to what he had programmed. In this case, the FO may not have detected the runway he used for programming was different due to not having an expectation it would have been incorrect. Expectations can influence perception, as people often hear what they expect to hear and see what they expect to see (Hawkins 1987). Research has also found that the pilots checking their own work are less likely to detect their own error than cross-checking by other crew members (Thomas, Petrilli, and Dawson 2004).

Independently cross-checking the runway-in-use

The captain did not separately obtain the ATIS as required by the operator’s procedures and likely relied upon the FO’s briefing that runway 03 was the runway-in-use. Further, he subsequently either did not check or detect that runway 21 was written on the flight planning documents nor that it was inconsistent with the information programmed into the FMGS.

Cross-checking is a fundamental element in all multi-crew operations, and is a vital mechanism for detecting errors. An exploratory study of error detection processes during normal line operations conducted by Thomas and others (2004) identified that cross-checking and monitoring of other crew actions was the most frequently observed error detection process. By not obtaining the ATIS independently and cross-checking the runway-in-use, this removed an opportunity for the captain to identify the programming error prior to take-off.

Non-detection of error

Research conducted during normal line operations has found over half of errors made by flight crew remain undetected (Thomas, Petrilli, and Dawson 2004). In this case, the error in the pre-flight programming remained undetected until after take-off. However, aside from cross-checking procedures, there were multiple opportunities available to the flight crew that would have provided them with the opportunity to identify the incorrectly entered runway. These were:

- Prior to, and during taxiing, the flight crew received taxi instructions and several clearances from ATC referencing runway 21, which were all read back correctly.

- The flight crew reported that, during take-off, they both noticed that the runway mode had not activated. However, they explained that the mode might also not activate if the instrument landing system was not available, rather than considering this as a programming error.

- While taxiing to the runway, there were guidance signs identifying the runway designation.

Of note, the flight crew received an electronic centralised aircraft monitor (ECAM) message around the same time ATC issued a hold-short instruction for runway 21. This message directed the flight crew’s attention to responding to the ECAM message at a time potential cues to the error were available, such as the instruction and airport signage. Further, although the flight crew reported at two separate times they felt there was something wrong with the preparation, they decided to continue with the flight. Even when cues to an error are provided there is a likelihood they can be dismissed or explained away if the information is not consistent with a person’s expectations (Hawkins 1987).

Turn contrary to clearance and published procedure

The FMGS was programmed for the runway 03 AVNEX TWO departure, which required a left turn after take-off at waypoint MIDLA. Therefore, after take-off from runway 21, the flight director indicated a left turn was required to capture the flight path to waypoint MIDLA to the north. The recorded flight data showed that the aircraft was turned left when at 223 ft above ground level.

This was contrary to the runway 21 departure, which required a right turn at waypoint NAVEY to the south not below 2,500 ft. This was also below the operator’s stipulated minimum turn height of 400 ft.

The left turn continued momentarily after the autopilot was engaged, but was quickly corrected when ATC assigned a heading instruction for the flight crew to regain the cleared flight path.

During the left turn, the flight crew had not realised the autopilot was flying a different path to what was actually cleared. A left turn was consistent with the crew’s expectations based on their preflight briefing for runway 03, although the low height of the directed turn should have been unusual and not consistent with the briefing. Following the flight director at this stage suggests the crew were relying on automation at the expense of their own monitoring, possibly due to an overreliance on automation (Parasuraman and Riley 1997).

Managing an unexpected situation after take-off The flight crew were in an abnormal situation when they identified the programming error in the FMGS. Air traffic control provided the flight crew with a number of heading instructions to regain the cleared flight path and also asked if operations were normal, which they confirmed was the case. As highlighted by Tullo (2010), ATC can potentially assist with problem-resolution in abnormal situations. In this case, ATC were unaware of the nature of the problem and the flight crew did not utilise them fully as an additional resource. By making ATC aware of the abnormal situation, it could have potentially reduced the flight crew’s workload in deciding subsequent action to evaluate and solve the problem. This may have reduced the need for the flight crew to reprogram the FMGS at a time when their workload would have already been high, as they were required to complete other checklists.

Although the flight crew correctly identified the problem, the captain’s chosen solution of reprogramming the FMGS increased workload during an already high workload situation. Such circumstances reduces the ability to monitor the flight path (Dismukes and others 1998).

With reference to the operator’s ‘fly’ then ‘navigate’ golden rule for pilots, the role of the captain as pilot monitoring was to focus on the flight parameters including heading, and communicate any deviations to the pilot flying. In this case, while ATC had provided the necessary navigation information (heading), the captain attempted to achieve this objective by manipulating the aircraft’s FMGS rather than selecting or flying to the given heading, at the expense of monitoring the flight parameters. During that time, the aircraft also turned through one of the assigned headings and an additional heading instruction was needed to be issued by ATC to return the aircraft back to its planned track.
Incident Facts

Date of incident
Nov 24, 2017


Flight number

Aircraft Registration

Aircraft Type
Airbus A320

ICAO Type Designator

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