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The ATSB has issued another warning about removing pitot probe covers after a Singapore Airlines A350-900 almost pushed back with the covers still fitted.
The final report into the incident at Brisbane Airport on 27 May 2022 found that Heston MRO, the contracted engineering provider for Singapore in Brisbane, had “not yet implemented an acceptable method for accounting for tooling and equipment prior to aircraft pushback”.
“Additionally, the procedural risk controls which were in place for the removal of the pitot probe covers were circumvented when the licenced aircraft maintenance engineer (LAME) certified for their removal in the technical log and removed a relevant warning placard from the flight deck, without visually or verbally confirming that they had been removed,” said ATSB chief commissioner Angus Mitchell.
The covers were noticed on the aircraft, 9V-SHH, by a refueller in an adjacent bay. When the LAME was alerted, they returned to the plane and removed the covers prior to pushback, with the flight then able to proceed to Singapore as normal.
“The final walk around inspection of the aircraft was also not conducted by the LAME or the headset operator. That inspection is intended to ensure that the aircraft is correctly configured for flight with all panels and doors closed and all covers removed,” said Mitchell.
“This incident demonstrates how assumptions and procedural omissions can lead to unsafe conditions; in this case, the potential for an aircraft to take-off with erroneous or absent airspeed indications.”
Pitot probe covers are needed at Brisbane to block invasive mud wasps, which nest in the tubes and can block them in as little as 20 minutes, according to the ATSB. The probes provide important airspeed data to aircraft systems and flight crew.
In a serious incident in 2018, a Malaysia Airlines A330 took off from Brisbane with its pitot covers still in place, and its crew had to conduct an emergency return landing without airspeed data.
While the ATSB was not able to formally establish that fatigue contributed to the occurrence, the investigation did note the LAME had reported the workload associated with their dual role of LAME/regional manager had become considerably more demanding following the COVID-19 pandemic.
“The engineering provider did not track the work-related hours of personnel with dual roles like the LAME involved in this incident (who was also the regional manager) for fatigue calculation purposes,” said Mitchell.
“This meant there was an increased risk of a fatigue-related incident with these personnel.”
The report notes that, since the occurrence, Heston MRO no longer requires the Brisbane regional manager position to undertake dual responsibilities, and tracks work hours of all employees for fatigue management purposes.
Also, during the ATSB’s investigation, a review of CCTV footage of pre-flight inspections by Singapore Airlines flight crew for the occurrence flight and others around the same time showed they were truncated, and not undertaken in accordance with company procedures.
“The pre-flight walk-around occurs before the pitot probe covers are to be removed, so this did not contribute to this incident,” noted Mitchell.
“Nonetheless, it was identified in our investigation as a safety issue, which Singapore Airlines has subsequently addressed.”
The airline, the report notes, has communicated with flight crews about the importance of pre-flight walk-around checks to be completed in their entirety and in accordance with the procedures.
The airline has also provided Heston MRO with pitot probe covers with longer streamers, to improve conspicuity.
