Regional airline Airnorth has boosted its pilot ranks and changed its rostering practices following an unintentional navigation error during a flight in January 2013, the aviation safety investigator says.
An Australian Transport Safety Board report found two pilots flying an Airnorth Embraer E170 on January 10 2013 from Darwin to the McArthur River Mine in the Northern Territory did not enter an intended navigation waypoint about 46 kilometres northwest of their destination in the aircraft’s flight management systems.
As a result, the aircraft diverged from its planned track, with the autopilot directing the aircraft to the initial approach fix rather than the navigation waypoint. Air traffic control spotted the error and notified the flightcrew.
The ATSB said the incident reinforced the importance of all pilots and operators conducting systematic and comprehensive checks of all data entered into flight management systems, as well as the importance of continually monitoring the effects of data input on an aircraft’s flightpath.
“Although the crew were conducting checks on this occasion, the checks were probably not systematic and comprehensive enough to identify the data input error,” the ATSB report said.
The report said not entering the navigation waypoint into the cockpit system was “almost certainly a skill-based error”.
The ATSB said the pilot reported having five hours sleep the night before the flight, which departed Darwin at 0700, while the first officer had about four hours sleep. The pair had about nine hours free of duty before the day of the incident.
“Due to restricted sleep in the previous 24 hours, the crew were probably experiencing a level of fatigue known to have a demonstrated effect on performance,” the ATSB said.
“Although the operator’s rostering practices were consistent with the existing regulatory requirements, it had limited processes in place to proactively manage its flightcrew rosters and ensure that fatigue risk due to restricted sleep was effectively minimised.
However, the ATSB added it was “difficult to conclude that fatigue actually contributed to the crew’s errors on this occasion”.
The ATSB report said Airnorth had increased its E170 flightcrew numbers by about 30 per cent since the incident, meaning flightcrews were doing less flight hours and there was greater flexibility in rostering crews.
Moreover, pilots were no longer rostered to have free of duty periods of less than 10 hours, unless the duty period had to be extended for operational reasons, although these were relatively rare occurrences.
“Airnorth advised that it had provided additional guidance in its operating procedures that placed further emphasis on the importance and associated considerations concerned with data entry into the flight management system (FMS) and the management of FMS navigation,” the ATSB said.
The ATSB report noted that the Civil Aviation Safety Authority issued revised fatigue management and flight and duty time requirements in March 2013, although this was not in response to this particular incident. The requirements were due to come into effect for existing operators in April 2016.
“The ATSB is satisfied that the changes made by the operator, and the increased requirements relating to fatigue management being imposed by the regulator, will reduce the risk associated with this safety issue,” the report said.