Qantas and Jetstar are being investigated by the ATSB for two incidents in which international jets were respectively excessively loaded with freight or contained undocumented consignments.

The safety investigations have not given rise to interim reports (which is the usual course of action) and both date back to last year and have only just come to light in a study it had conducted of “Aircraft Loading Occurrences” July 2003-June 2010.

And while the title might be enough to instantly cure insomnia, the contents are a sharp wake-up call for Australian airlines.

On March 6 last year at Sydney Airport, a Qantas A330-300 bound for Hong Kong was excessively loaded with freight, making the jet one tonne above its maximum permitted take-off weight.

It isn’t known if this was detected before or after take-off.

On July 5 last year in an incident involving a Jetstar A330-200 at Sydney some 700 kilograms of “unmanifested freight was loaded onto the aircraft without authorisation” at Sydney International terminal where it was about to operate the extension of an overseas originating flight to Melbourne carrying a mixture of international and joining domestic passengers.

The Jetstar incident leaves open criminal possibilities at one extreme, or negligence by Jetstar at the other.

Just how undocumented freight on a mixed international/domestic service came to be placed on a Jetstar flight at Australia’s major gateway airport with its claimed high levels of security is of possible interested to more than the air safety investigator.

Jetstar has already been caught out making illegal changes to the standard operating procedures of one of its Airbus A320 jets in the infamous missed approach by a flight from Christchurch to Melbourne Airport in July 2007.

The then CEO of Jetstar and now Qantas CEO Alan Joyce is due to face a Senate inquiry into that matter in February as it examines calls for improved training and safety standards in Australian carriers.