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”.
Thanx again.
So how ignorant can one be? Would you be good enough to explain, p’raps either here or in another Crikey clarifier, what a higher thrust setting may be and why it may be needed?
The only bad questions are the ones we never ask….(!)
The RR engines are certified to generate a maximum thrust of 75,000 lbs each. Singapore Airlines and Lufthansa have chosen to use up to 70,000 lbs of that certified maximum output. Qantas has chosen to have up to 72,000 lbs (give or take a few lbs here or there) available, specifically to enable the jet to take off at its maximum operating weight when flying out of Los Angeles to Sydney or Melbourne. There is nothing unusual about airlines choosing to use less than an engine can deliver, nor choosing various optional power capabilities.
The emergency airworthiness directive which applies to the the Trent 900s applies to all of them, no matter what thrust rating the airline users have chosen.
It might seem tempting to relate the Qantas experience with QF32 to the fact that on some flights Qantas used these engines to generate more thrust than the other airlines, and thus explain why this misfortune had befallen it rather than Singapore Airlines, which has been flying more A380s and for longer than Qantas.
But we still don’t know if this is a crucial factor. We may learn more about this in the interim or preliminary report into the incident due by December 3.
I am updating this story for Plane Talking later in the day.
Thanx muchly.
Again, rather simplistically, if an engine is certified to generate a maximum thrust of 75,000 lbs it seems to me that it should be useable at 75,000 lbs. If the engine is safe only up to 70,000 lbs that seems to me a problem for its certification. I presume engines are certified by some regulatory body, which surely is following this investigation rather closely.
One of the reasons airlines generally don’t ‘thrash’ their engines to the design limit, or the equivalent of ‘beyond the red line’ on the tachometer of a car, is premature wear and thus cost.
In the 707 and DC-8 days no such sensibilities existed. It was full throttle just about all the way, and lots of replacement engines, as well as flights that measured by sector times, were definitely faster than today’s.
Qantas used to be one of the best airlines in the world. So, what happened? Can’t we stand up to high standards we used to have?
Or perhaps we should start listening to people like Dick Smith? He warned and predicted EVERYTHING that is happening now.