Virgin Australia B738 at Cairns on Oct 24th 2022, descended below minimum safe height

Last Update: February 28, 2023 / 21:00:04 GMT/Zulu time

Bookmark this article
Incident Facts

Date of incident
Oct 24, 2022

Classification
Incident

Flight number
VA-793

Aircraft Registration
VH-VUT

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

A Virgin Australia Boeing 737-800, registration VH-VUT performing flight VA-793 from Brisbane,QL to Cairns,QL (Australia), was on a RNAV HENDY 8A standard instrument approach BARIA transition to Cairns when the aircraft descended below the minimum safe height with air traffic control issuing a low altitude warning to the crew and instructing them to return to safe altitude. The crew climbed back to safe altitude, commenced a missed approach and landed sfely on second approach.

The ATSB released their preliminary report summarizing the sequence of events:

At 1945 local time, the aircraft was cruising in darkness at flight level (FL)2 380 about 215 NM to the south of Cairns. At that time, air traffic control (ATC) provided the crew with clearance to conduct the Cairns HENDO 8Y standard arrival (STAR) via the BARIA waypoint3 transition.

The flight crew entered the HENDO 8Y STAR into the flight management computer (FMC) and selected the BARIA transition. The HENDO 8Y STAR progressed into the required navigation performance (RNP) Y instrument approach for runway 33 at Cairns. While clearance for the approach had not been provided at that time, the crew anticipated the clearance and loaded the approach into the FMC. From HENDO, the minimum altitude for commencing the RNP Y approach was 6,800 ft above mean sea level (AMSL). The HENDO waypoint was located within the 6,500 ft minimum sector altitude (MSA)4 segment to the south of Cairns.

The approach procedure had two different initial approach fixes (IAF) (Figure 2) with associated paths to a common intermediate fix (IF) at waypoint CS540. From the BASIL IAF, the approach proceeded via CS520, CS521 and CS523, and from the HENDO IAF via CS522 and CS523. In order to load either path into the FMC, the flight crew needed to select one of the two approach transitions.

The flight crew did not recognise that an approach transition selection was required and consequently did not select one. As a transition had not been selected, the FMC presented a discontinuity in the entered flight path at the HENDO waypoint (see the section titled Flight management computer). The flight crew misidentified the approach IF, CS540, as the IAF and resolved the FMC discontinuity by connecting HENDO to CS540. This selection removed the 6,800 ft descent altitude constraint associated with HENDO in the RNP approach programming.

At 1954, when the aircraft was 136 nm south of HENDO, ATC cleared the flight to track direct to the HENDO waypoint and 6 minutes later the crew commenced descending the aircraft. At 2010:51, when the aircraft was about 11 NM southeast of HENDO, ATC provided the crew with clearance to conduct the RNP Y runway 33 approach.

One minute later, the aircraft approached HENDO descending through about 7,300 ft with the autopilot engaged and an altitude of 6,800 ft selected in the autopilot mode control panel. At about that time, the captain selected the approach’s minimum descent altitude of 800 ft, but sensed that this selection was incorrect and therefore reselected an altitude of 6,800 ft. The captain then reviewed the approach briefing, confirmed that the aircraft was tracking as intended and the vertical navigation autopilot mode was active and again selected 800 ft.

At 2011:38, about 7 NM prior to crossing HENDO, the aircraft descended below 6,800 ft and 9 seconds later descended below the 6,500 ft MSA. Six seconds later, at 2011:53, ATC observed that the aircraft had descended below 6,800 ft and contacted the crew to confirm the aircraft’s altitude. The captain then reselected 6,800 ft and manually arrested the descent. ATC then issued a low altitude alert to the crew and advised them to climb immediately. Three seconds later, at 2012:07, the aircraft stopped descending at about 5,920 ft and then commenced a climb. At 2012:28, the aircraft climbed back above 6,800 ft. No ground proximity warning system alerts were generated during the incident.

A missed approach was then commenced, and the crew conducted a second approach without further incident.
Aircraft Registration Data
Registration mark
VH-VUT
Country of Registration
Australia
Date of Registration
EmjqAhlpAmpgAmfc Subscribe to unlock
Airworthyness Category
Ldphfmndfgfhefngdj Subscribe to unlock
TCDS Ident. No.
Manufacturer
THE BOEING COMPANY
Aircraft Model / Type
737-8FE
ICAO Aircraft Type
B738
Year of Manufacture
Serial Number
Maximum Take off Mass (MTOM) [kg]
Engine Count
Engine
Mcnnfnblf hmglpkmdeehpjnAnikbmeeh mcdbAhfhfAd Subscribe to unlock
Main Owner
QljbbA lmgAec fccbmikpAkdcqnqlleApcmnjqdkdipnfpnnflmhhnldiqqfmmfhnmlg qbphhcdkg ngejqneig mjileqchmhhlclqqldjjA jidkj dllgc Subscribe to unlock
Main Operator
kgen pfhnnbmc fkmfkAmiekbAjqApkmklbAfpfikeffdhhAdfdjb dfikAnq AnbcjgnAde mh eAihjdj bfjimigeecic Subscribe to unlock
Incident Facts

Date of incident
Oct 24, 2022

Classification
Incident

Flight number
VA-793

Aircraft Registration
VH-VUT

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

This article is published under license from Avherald.com. © of text by Avherald.com.
Article source

You can read 2 more free articles without a subscription.

Subscribe now and continue reading without any limits!

Are you a subscriber? Login
Subscribe

Read unlimited articles and receive our daily update briefing. Gain better insights into what is happening in commercial aviation safety.

Send tip

Support AeroInside by sending a small tip amount.

Related articles

Newest articles

Subscribe today

Are you researching aviation incidents? Get access to AeroInside Insights, unlimited read access and receive the daily newsletter.

Pick your plan and subscribe

Partner

Blockaviation logo

A new way to document and demonstrate airworthiness compliance and aircraft value. Find out more.

Virtual Speech logo

ELITE Simulation Solutions is a leading global provider of Flight Simulation Training Devices, IFR training software as well as flight controls and related services. Find out more.

AeroInside Blog
Popular aircraft
Airbus A320
Boeing 737-800
Boeing 737-800 MAX
Popular airlines
American Airlines
United
Delta
Air Canada
Lufthansa
British Airways