Qantas Flight 72, registration VH-OJU performing flight QF-72 from Dubai (United Arab Emirates) to Perth,WA (Australia), was descending towards Perth when the crew stopped the descent at FL070 and decided to return to Dubai. During the initial approach to Dubai the aircraft suffered a number of pitch excursions initiating at about 5000 feet AGL,
the autopilot disconnected automatically and manually several times over a period of about 30 minutes until landing back in Dubai. During one such pitch up event, which was captured on cvr audio,
impact forces were recorded as well as sounds consistent with main gear tires bursting after contact with runway 29L at 10:40AM local time. The aircraft came to a stop off the
left hand side of the runway on soft sand about 50 meters from paved surface. There were no injuries, the aircraft sustained substantial damage.
What Are The Reasons For The Malfunction?
The Investigation found that the Directional Control Computer (DCC) software had been loaded with the wrong navigation database, including incorrect coordinates of waypoints.
This error was undetected by the crew. The aircraft’s avionics systems included an autopilot capable of each lateral axis and a flight director capable of controlling both vertical and lateral axes simultaneously.
During initial approach to Dubai runway 29L, while conducting an RNAV (GNSS) approach in LNAV+VNAV mode,
the PF applied nose up inputs on the control column while activating the “Flight Level Change” function on the Mode Control Panel resulting in full nose up pitch commands.
Subsequently, when disconnecting the autopilot about 7nm before touchdown,
The Hero Pilot
Kevin Sullivan , the captain at that time, managed to control the flight and land safely and saving 315 people despite a number of issues. He encountered many problems:
1) The “flight level change” function combined with the autopilot and flight director turned off so he had no way to descend from 7,000 feet
2) The airplane was too heavy at landing weight but he didn’t have enough fuel to postpone the landing long enough so they were forced to weigh their options. For example:
3) One engine was not working properly but one by one between 2000-5000 ft, they restored full capacity again. They were able to restore power just in time before going below 5000 feet which is normally required by regulations.
4) Landing gears were not working properly; also they observed sparks coming from the tires
Automation Technologies are a double-edged sword
The fight between automation and piloting is an issue that has been raised in many accident investigations. The complex systems found in the modern aircraft are often so reliable that pilots do not have to be trained or prepared when it fails
The investigation identified that there exists a risk that crews may place undue reliance on, and expect intervention by, their aircraft’s automated systems in circumstances which they have not fully assimilated. Unstable approaches due to lack of training in manual flight were recognised as being a factor in several previous accidents
A number of previous safety studies reported an over-reliance on automation with the associated degradation in the skills required for manual flying
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