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ASN Wikibase Occurrence # 204517
Last updated: 23 July 2018
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Date:19-FEB-2016
Time:22:01 LT
Type:Silhouette image of generic A320 model; specific model in this crash may look slightly different
Airbus A320-216
Owner/operator:Indonesia AirAsia
Registration: PK-AXY
C/n / msn: 5359
Fatalities:Fatalities: 0 / Occupants: 102
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:17 km WSW Perth Airport, WA -   Australia
Phase: Approach
Nature:International Scheduled Passenger
Departure airport:Denpasar-Ngurah Rai Bali International Airport (DPS/WADD)
Destination airport:Perth Airport, WA (PER/YPPH)
Investigating agency: ATSB
Narrative:
On the evening of 19 February 2016, an Airbus A320 aircraft, registered PK-AXY and operated by Indonesia AirAsia was on a scheduled passenger service from Denpasar, Indonesia to Perth, Australia. During cruise, the captain’s flight management and guidance computer (FMGC1) failed. Due to the failure, the flight crew elected to use the first officer’s duplicate systems. For the aircraft’s arrival in Perth there was moderate to severe turbulence forecast below 3,000 ft with reports of windshear. The crew commenced an instrument landing system (ILS) approach to runway 21.

During the approach, the flight crew made a number of flight mode changes and autopilot selections, normal for an ILS approach with all aircraft operating systems available. However, some of those flight modes and autopilot selections relied on data from the failed FMGC1 and the autothrust system commanded increased engine thrust. The crew did not expect this engine response and elected to conduct a go-around. With an increasing crosswind on runway 21, the crew accepted a change of runway, to conduct a non-precision instrument approach to runway 06.

With the time available, the first officer programmed the new approach into his FMGC and conducted the approach briefing. During this period, the captain hand flew the aircraft and manually controlled the thrust. During the approach to runway 06, the crew descended the aircraft earlier than normal, but believed that they were on the correct flight path profile.

While descending, both flight crew became concerned that they could not visually identify the runway, and focused their attention outside the aircraft. At about that time, the approach controller received a “below minimum safe altitude” warning for the aircraft. The controller alerted the crew of their low altitude and instructed them to conduct a go-around. The crew then conducted another approach to runway 06 and landed.

Contributing factors:
- The flight crew’s diagnosis of the captain’s failed flight management guidance computer was accurate, but after they did not find the procedure to follow, the failure was not appropriately managed. This resulted in degraded systems capability for the approach.
- The flight crew had a limited understanding of how the captain’s failed flight management guidance computer
would affect the use of the aircraft’s automated systems during the instrument landing system approach. This meant that their decision to engage autopilot 1 resulted in the frozen data stored in the failed guidance computer being utilised by the autoflight system, leading to an unexpected increase in engine thrust and prompted the crew to conduct a missed approach
- The unresolved system failures, combined with the conduct of a missed approach procedure and the subsequent runway change increased the flight crew's workload. This likely reduced their ability to analyse the actual extent to which their automation was degraded, and effectively manage the subsequent approaches.
- During the first runway 06 non-precision approach, the flight crew’s focus of attention was outside the aircraft, attempting to locate the runway. This distraction, along with their unfamiliarity with the approach procedure
- inhibited their ability to monitor and maintain the correct flight profile and altitude during the approach. The flight crew did not detect that the aircraft had descended below the segment minimum safe altitude for that stage of the approach

Sources:

https://www.atsb.gov.au/publications/investigation_reports/2016/aair/ao-2016-012/

Accident investigation:
cover
  
Investigating agency: ATSB
Status: Investigation completed
Duration: 1 year and 11 months
Download report: Final report


Images:


Revision history:

Date/timeContributorUpdates
16-Jan-2018 07:13 harro Added
16-Jan-2018 07:16 harro Updated [Photo, ]

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