Poor visibility, an incorrect assumption, and non-specific operator procedures contributed to a Metroliner freight aircraft taking off from Townsville with both of its pitot tubes still covered, an ATSB final report details.
The incident occurred at night, in heavy rain on 10 February 2025, when the Fairchild SA227 twin turboprop was being prepared for a freight flight from Townsville to Brisbane, Queensland.
The same aircraft had been flown into Townsville by the same captain and first officer on the morning of the incident. After landing in Townsville around 0800, the flight crew had conducted a terminating check and installed engine bungs, static port covers, and pitot tube covers, before ending their duty and spending the day resting.
After coming back onto duty shortly after 1800, the flight crew began to prepare the aircraft for its return trip to Brisbane.
The first officer removed the engine bungs and static port covers, but was unable to reach the pitot tube covers, so asked the captain to remove them. The captain said they would remove the tube covers but subsequently forgot.
The first officer incorrectly assumed the captain had removed the covers, and the flight crew proceeded to taxi for take-off.
Due to the conditions, neither crew could see the pitot tube covers on the nose of the aircraft during their taxi.
"The flight crew recognised slowly rising airspeed indications during the take-off roll but did not identify that this was symptomatic of blocked pitot tubes," ATSB Director of Transport Safety Stuart Macleod said.
Observing the aircraft's groundspeed on a separate GPS unit, and uncertain if there was sufficient runway in wet weather to safely stop, the captain elected to continue the take-off.
During the climb, the flight crew became aware the pitot covers had been left installed on the pitot tubes. The crew was then able to return to Townsville for an uneventful landing.
"This occurrence highlights the importance of conducting an airspeed check early in the take-off run and recognising if something is not as expected, so the take-off can be safely rejected," Mr Macleod said.
He said the occurrence also highlighted a discrepancy between the operator's expectations and what was detailed in its procedures.
"When the flight crew began their evening shift shortly after 1800, the captain did not believe a daily inspection was required, as one had already been completed earlier that day," Mr Macleod explained.
"They also believed a crew change inspection was not required, as the crew had not changed."
The aircraft operator, Sharp Airlines, stated it expected a full daily inspection of the aircraft was required after termination checks had been completed, but this was not stated in its procedures.
Further, the final visual check conducted by the first officer prior to closing the doors, as stated in the procedures, did not include checking the pitot covers had been removed.
Sharp Airlines has advised it is reviewing the standard operating procedures to ensure clarity of process for pre-flight inspections.
"This scenario illustrates the importance of procedures clearly stating what inspections are required, and when," Mr Macleod said.
"Flight crew pre-flight inspections are an important risk control, but if they are not done correctly, it increases the risk of defects not being identified, and/or the aircraft not being correctly configured for flight."
You can find here the report: Unreliable airspeed indication on take-off involving Fairchild SA227, VH-UZN, Townsville Airport, Queensland, on 10 February 2025
