Two separate occurrences through which 737 airliners flew under minimal altitude on the identical arrival and method into Cairns Airport, show the dangers related to information entry errors, and the significance of thorough and impartial cross-checks.
The Australian Transport Security Bureau launched an investigation after being notified of two separate incidents, on 24 and 26 October 2022, involving Boeing 737-800 – one operated by Virgin Australia in darkish evening circumstances, the opposite by Qantas in clear day circumstances – on scheduled passenger flights to Cairns, Queensland.
In every incidence flight crews entered the identical commonplace arrival (HENDO 8Y) and method (RNP Y runway 33) into their flight administration computer systems.
Nevertheless, neither flight crew chosen the required method transition leading to a discontinuity within the programmed flight path.
When introduced with the discontinuity by the flight administration pc, each flight crews resolved it by manually connecting the arrival waypoint HENDO to the intermediate method repair waypoint, famous on the method chart.
This inadvertently eliminated the 6,800 ft descent altitude constraint related to the preliminary method repair waypoint in every plane’s programmed flight path, and in consequence each plane descended under that constraint.
The Qantas crew recognised the descent error and stopped additional descent, whereas in each instances air visitors management additionally alerted the flight crews of their low altitude.
The Virgin plane performed a missed method earlier than conducting a second method and landed with out incident. Air visitors management supplied the Qantas crew with clearance for a visible method, earlier than the plane landed with out additional incident.
“These occurrences spotlight the dangers related to information entry errors that end in incomplete or incorrect info being entered in flight administration techniques,” stated ATSB Director Transport Security Stuart Macleod.
“Whereas no-one is immune to those errors, the chance might be considerably diminished by way of thorough and impartial cross-checks between pilots.
“Good communication, adherence to working procedures, and clear and efficient process chart design are essential to secure flight.”
The investigation additionally discovered that the vertical profile depiction on the Jeppesen RNP Y runway 33 method chart didn’t embody the waypoints HENDO, CS522 and CS523 and the map introduced the data related to these waypoints over dense topographical info.
This possible restricted the power of each crews to establish the descent restrictions related to these waypoints.
You’ll find right here the report: Flight under minimal altitude occurrences, 40 km south of Cairns Airport, Queensland on 24 and 26 October 2022
