The ATSB has ordered new tests to determine if electromagnetic inference from military installations near Learmonth in WA is a possible cause of serious incidents involving Qantas A330s.

The interim factual report into the QF 72 accident on 7 October, which seriously injured 12 people during an emergency descent to Learmonth reveals that two similar occurrences have occurred to this type of Airbus in Qantas service also within 1000 kilometres of the nearby Harold E Holt naval communications base and its very low frequency transmitters.

One of those incidents, not previously revealed, happened to the same A330, VH-QPA, on 12 September 2006 while 950 kilometres north of Learmonth on a Hong Kong-Perth service.

The other incident which had previously been identified happened to Qantas A330 VH-QPG when it was 700 kilometres south of the base.

Neither of those incidents involved the briefly severe losses of control that occurred on 7 October.

The locations are shown on the above diagram in the report. Not shown is the location of another similar control failure in a Jetstar A330, VH-EBC on 7 February while flying between Sydney and Saigon which was 3250 kilometres from Learmonth and 700 kilometres north-west of Sydney. More on this development later today.