In what may not seem completely reassuring for passengers, Qantas is resuming A380 flights to London from Saturday but isn’t yet game to trust the giant airliner on trans-Pacific flights between Australian cities and Los Angeles.

The cautious restoration of A380 services using the Rolls-Royce Trent 900 engines avoids routes where Qantas was routinely using a slightly higher thrust setting than Singapore Airlines or Lufthansa, the other two carriers using the same power plants on the double-decker airliner.

Qantas has three A380s stranded at Los Angeles since it grounded its fleet of six the same day that the violent engine failure seriously damaged the wing and control systems of the jet operating QF32 from Singapore to Sydney with 466 people on board.

The first of these jets is about to be flown back from Los Angeles without passengers to operate QF31 from Sydney to London this Saturday.

Qantas CEO Alan Joyce said that subsequent deployments of its other A380s will be announced later.  Qantas also takes delivery of two new A380s in December and one more in January.

It says that in consultation with CASA, Rolls-Royce and Airbus  it is now satisfied that it can begin restoring the use of the giant jet, except, for the time being, where it often needs slightly more thrust from its engines than on any of the routes flown by Lufthansa and Singapore Airlines, neither of which grounded their fleets for significant periods after the QF32 incident.

Qantas operations regularly require the use of that additional power to depart with a maximum take-off weight from Los Angles on flights of more than 14 hours duration to Sydney or Melbourne.

Although not mentioned by Qantas this morning, the deferral of A380 flights returning to the trans-Pacific routes also avoids the jet being a long way from emergency airports in the event of another engine mishap.

The A380 operating QF32, Nancy-Bird Walton, was aloft for more than 100 minutes after the engine flew apart, puncturing the wing, fuel tanks and control cabling, and disabling half of the jets hydraulic systems.

It is now being examined in Singapore, where it will remain for all or part of a very long repair process.

Along most of the usual routes flown between Singapore and London, an A380 can remain within two hours flight time of an alternative airport, and will for much of those 12-13 hour flight sectors, be much closer than that to multiple suitable emergency runways.

The inquiry into the incident led by the ATSB is in its early stages, with an interim report due by December 3.  An oil fire in or around the structural cavity between the high and intermediate pressure  sections of the engine “may have caused a sequence of events leading to the failure of the Intermediate Pressure Turbine disc”,  according to the emergency airworthiness directive updated by the European Aviation Safety Agency last night.

As a result Qantas, Singapore Airlines and Lufthansa are compelling to subject each of their Rolls-Royce engines to an intensive set of examinations and tests once every 20 flights (or once in 10 flights when the engine is first replaced on the wing).

Qantas says it has voluntarily decided to kept the jets off  routes where it routinely requires a higher thrust capability until “further operational experience is gained or possible additional changes are made to the engines”.