SYDNEY, Oct. 4 (Xinhua) -- Australia's QantasLink plane avoided a potentially serious incident after it completed a trip from Canberra to Sydney using incorrect data about the plane's weight and temperature.
News Corp reported on Tuesday that an investigation by the Australian Transport Safety Bureau into the June 20 incident has found that a tired crew and last-minute changes to the aeroplane's passenger numbers meant the wrong takeoff data was used for the flight.
The incident involved a Cobham-operated Boeing 717-200 that was flying to Sydney with 91 passengers and five crew on board.
The captain had prepared for a "flex" takeoff based on an assumed outside temperature of 39C.
Flex allows pilots to use reduced thrust to take off, which reduces the wear and tear on plane engines.
However, that flex temperature was revised down to 34C when 22 additional passengers were loaded on to the plane after the cockpit checklist had been completed.
While the captain recorded the new temperature, it was scribbled over the initial 39C figure, which was then used to calculate the engine's required thrust.
Despite the error, the flight continued to Sydney and landed without incident.
In its investigation into the incident, the ATSB found that both members of the flight crew assessed that tiredness because of their early morning start may have contributed to the flex temperature error, but that they were fit to continue to operate for the rest of the day's duty.
"The flight crew commented that a combination of distraction by cabin crew and ground personnel while re-entering data, a reduced state of arousal following a high workload instrument approach, and possibly tiredness from an early start may have contributed to their omitting to enter the correct flex temperature," the ATSB said.
In its official report into the incident, the bureau said the use of inaccurate takeoff reference data could have potentially serious consequences.
In a 2011 report, the ATSB highlighted the consequences of failing to use correct data for flight calculations, saying that tail strikes, runway overruns and degraded handling qualities could all occur.
"It is imperative that the aviation industry continues to explore solutions to, firstly, minimise the opportunities for takeoff performance parameter errors from occurring and, secondly, maximise the chance that any errors that do occur are detected and/or do not lead to negative consequences," it said.
Cobham Aviation Services, which hires the crew, said they would ensure their pilots used a new takeoff and landing data collection card if new information needed to be added or updated.
