Lessons from one of Australian aviation’s most serious safety incidents appear not to have been learnt after a Singapore A350 came within just two minutes of departure with key sensors covered up.
The new incident on 27 May occurred two months after the ATSB published its four-year report detailing a near identical situation on a packed A330 in Brisbane where the aircraft departed.
The ATSB then noted how speed sensor problems in 1996 led to two fatal crashes that killed more than 200 people.
On Friday, a new preliminary ATSB report, released early, revealed how a Singapore A350-941 was just two minutes from departure yet had covers on its key pitot speed sensors.
The investigation revealed the two aircraft maintenance engineers tasked with the removal of the covers failed to do so.
The potential safety incident was only prevented because a quick-thinking aircraft refueller on an adjacent bay noticed the covers were on and alerted the engineers.
Aircraft are fitted with pitot probe covers when parked at Brisbane Airport to prevent mud wasps building nests within and blocking their pitot probes, which are used to measure air pressure to calculate airspeed.
“A known hazard at Brisbane Airport, mud wasps can rapidly build nests in aircraft pitot probes,” noted ATSB director of transport safety Dr Michael Walker.
“An aircraft being cleared to commence taxiing and then commence take-off with all pitot probe covers still fitted is a serious event.”
Two maintenance contractor ground crew engineers — a licensed aircraft maintenance engineer (LAME) supervising an inexperienced aircraft maintenance engineer (AME) — had been assigned to conduct scheduled receipt, dispatch, certification, and maintenance duties for the Singapore Airlines A350 aircraft during a two-hour turnaround at Brisbane.
As pushback approached, the covers remained in place until an aircraft refueller, working at an adjacent bay, observed them and alerted the supervising LAME.
The pitot covers were then removed two minutes before expected departure, and pushback occurred shortly afterwards.
As part of its investigation to date, the ATSB has interviewed the LAME, AME, the refueller, and has reviewed airport security video, which did not show that the required final walk-around of the aircraft was conducted by either the LAME or the AME prior to dispatch.
“From here, the investigation will include examination of flight crew pre-flight inspection procedures, engineering final walk-around procedures, and induction training procedures,” said Dr Walker.
“It will also examine the engineers’ training records, policies and procedures around fatigue and change management, and more security video recordings.”
Australian Aviation reported in March how a four-year ATSB report identified a catalogue of basic errors made by Malaysia Airlines staff that led to the previous pitot probe incident on a packed A330 at Brisbane.
The ATSB said in a statement its investigation into the 2018 incident was “one of its most substantive and complex” in recent years and highlighted poor decisions made by Malaysia Airlines pilots and crew, alongside those of other organisations.