Investigators have revealed that a Singapore Airlines Airbus A350-900 at Brisbane was only prevented from departing with its pitot covers still fitted because an alert refueller on the adjacent parking bay alerted ground personnel.

The aircraft (9V-SHH), operating flight SQ256 to Singapore on 27 May 2022, had undergone a 2h turnaround and was preparing for pushback.

Two aircraft engineers from Heston MRO were carrying out maintenance and dispatch duties. One of the two was supervising the work on SQ256 – the other engineer was a new hire – while also assisting with turnaround of another aircraft.

Covers were fitted to all four pitot probes at Brisbane in line with company procedures. The supervising engineer entered the cockpit to record this cover-fitting in the technical log, and place a warning placard on the engine controls.

When the aircraft’s first officer conducted a pre-flight walk-round, about 1h later, he probably saw that the pitot covers were in place, as required, says the Australian Transport Safety Bureau.

After attending to another aircraft, the supervising engineer returned to SQ256 to discuss fuel figures with the colleague and the crew, before re-entering the cockpit, removing the placard and clearing the log entry for the pitot-cover fitting.

According to the inquiry, this was done “without visual or verbal confirmation” that the pitot covers had been removed.

The supervisor and the colleague then spoke on the ground, near the A350’s nose, about attending to another aircraft. The colleague then remained with SQ256 to conduct pushback headset duties.

Engineer and SIA A350 incident-c-ATSB

Source: ATSB

Pictured by an adjacent A330, the refueller warns the engineer about pitot covers on the SIA A350 (out of shot)

But around this time, says the inquiry, an aircraft refueller working on an adjacent bay noticed that SQ256 appeared ready for pushback but that its pitot covers were still fitted.

The refueller immediately pointed to the A350, informing the supervisor that the covers remained attached.

SQ256’s crew had requested pushback from air traffic control, and turned on the aircraft’s beacons, around the same time as the supervisor returned to the aircraft to alert the colleague. The airbridge was being withdrawn from the A350 when its crew was told to standby because the pitot covers were being removed.

SIA A350 pitot incident pushback-c-ATSB

Source: ATSB

Engineers belatedly removing the A350’s pitot covers as SQ256 prepares for pushback

The inquiry highlights a similar occurrence at Brisbane in July 2018 during which a Malaysia Airlines A330-300 – which had also been attended by Heston MRO, then known as AMSA – took off with pitot covers still in place.

As a result of that investigation, Heston MRO implemented procedures to improve the consistency of pitot-cover use and better control measures over tools and equipment used during turnaround.

These measures, ironically, included introducing the cockpit placard to be put in place each time pitot covers were fitted.

Investigators examining the SQ256 incident found that Heston MRO, despite the earlier A330 incident, had “not yet implemented an acceptable method” to account for tools and equipment prior to pushback.

The inquiry also draws attention to the possible risks of fatigue, noting that Heston MRO did not track work hours of personnel with dual roles. It states that the supervising engineer had also been serving as Brisbane regional manager, and the demands of these posts had become more demanding in 2022 as aircraft were removed from storage post-pandemic and airline turnarounds increased.

SIA A350 pitot incident-c-Heston MRO via ATSB

Source: Heston MRO via ATSB

Pitot covers with longer, more visible, streamers were subsequently introduced

Heston MRO no longer requires the Brisbane regional manager to hold dual responsibilities, and has started tracking employees’ work hours for fatigue management.

Singapore Airlines has provided Heston MRO with pitot covers featuring longer streamers, to make them more visible. The carrier has also underlined the importance of pre-flight checks to cockpit crews, after the inquiry found that the “majority” of pre-flight inspections observed around the time of the incident – including that for SQ256 – were “truncated”.

Investigators credit the response of the refueller who drew attention to the presence of the pitot covers.

“This serves as a reminder that all line personnel have a safety role and should always speak up if they see or feel that something is not right,” the inquiry states.