Cover Design and Placement
The fan cowl static port covers on VH-ZNJ were of a type that typically incorporated a streamer hanging down. However, the Boeing procedure for these covers required the 1-metre-long tail to be taped down. Additionally, the fan cowl port covers were positioned below eye level, making them harder to see without bending down.
Documentation Gaps
Qantas parking documentation for the aircraft referenced the Boeing procedures, but the restore instructions did not. This represented a missed opportunity for engineers to readily access current procedures and determine which ports were covered.
Maintenance Procedure Ambiguity
The Qantas maintenance procedures required covering the static ports but did not specify their locations. This allowed for potentially different interpretations by licensed aircraft maintenance engineers (LAMEs). The emphasis of warnings was more aligned with the fuselage (ADRS) static ports than with the fan cowl or vertical fin covers. Since different engineers might park and restore the aircraft, listing static port locations with separate endorsements would have eased identification.
Inspection Shortcomings
A safety observer (SO) found a pitot cover on the ground at the beginning of their exterior inspection and reported continuing the inspection while seeking an engineer. It could not be determined if this distraction affected their non-normal exterior inspection. The dispatcher did not conduct exterior inspections according to documented procedures, reducing the effectiveness of this risk control.
Expectation and Bias
Research indicates that people detect expected targets more readily and may miss unexpected ones. LAME 2 did not expect the fan cowl ports to be covered and therefore did not specifically check them. Flight and dispatch crew inspections typically occur after engineering releases the aircraft, with no issues usually found. The SO stated an expectation that engineering had completed an inspection, likely leading to inspections with no expectation of finding anomalies. The dispatcher reported that, had they seen the tape covering the fan cowl ports, they might not have questioned it due to an assumption it was required.