The uncontained Trent 900 engine failure on a Qantas Airways Airbus A380 last November was a high profile incident that called the attention not only of the aviation community. The international media spread news about the incident quite instantly and aviation professionals worldwide exchanged e-mails as soon as any new image or information was available.
General public do not know how serious an uncontained engine failure can be, nor how many lives this type of failure has already claimed. News agencies and even the specialized press presented a large amount of visual material about the damage the aircraft suffered. All that was published shows quite nothing compared with the actual internal destruction on structural components, systems, wiring, tubes and other parts of the A380 wing. The aircraft landed thanks to the ability of the crew, a project where fail safe design has been handled magnificently and, of course, luck (had the fuel ignited, it would have had the same fate as the Concorde).
All passengers and crew deboarded safely in Singapore after the emergency landing. The passengers were boarded the next day on a Boeing 747 with Rolls-Royce RB211 turbines to Sidney. When passing through 2,000 ft, number one engine lost a compressor blade, was shut down and the aircraft made an emergency landing. After engine replacement, it returned to service.
But, unfortunately the story does not finish here. Last winter a Qantas 747 with RB211 engines, departing from San Francisco for a 14 hours trans Pacific flight, suffered an engine failure. On February 2011, an Airbus A380 with RR Trent 900 engines had to shut down one of the engines that was leaking oil. The flight proceed to the destination on the remaining 3 engines. This week, ending 20 may 2011, a Qantas 747 returned to Bangkok due to high temperatures and vibration on one of its RB211 engines and last Monday a RR Trend 700 on a Cathay Pacific flight caught fie.
As usual, all these events are under investigation. The uncontained failure of the RR Trend 900 on the Airbus A380 was result of a manufacturing problem. How it was not detected on inspections must never happen again. The problematic component being replaced in all engines affected. Oil leaks causing power loss had been identified as result of wrong torque applied on an oil tube after inspection. Maintenance procedures should be revised. The failures on the RB211 seen to be more frequent on Qantas than other airlines and started to be more frequent when the airline closed its RB211 maintenance facility in Sidney. As the RB211 is an ageing engine, maybe some modifications could be implemented and also maintenance procedures revised to have them as safe as they used to be.
Rolls-Royce is one of the few companies that dominate the technology of jet engines. All engines from RR have been solidly dependable and some are unique, true legends, as the Pegasus (that powers the Harrier) and the Olympus (only engine for the Concorde). Although the high profile incident with the Trent on the A380 did not shadow Rolls-Royce public image, the same cannot be said about its financial results. All affected engines had to be removed from the aircraft and the non conforming component retrofitted. Qantas, that has even mentioned the possibility of going to justice for the loses, reached an agreement with Rolls-Royce, but the terms have not been made public. The company identified the problem and assumed responsibility for the fault but could have been handling better the situation on the aftermath of the incident (informing more, mainly with some technical details about an uncontained failure in a test bench – if you do not say, people begin to wonder). The engine that failed on the test was a Trent1000, that is the lead powerplant for the Boeing 787 and has received FAA approval for 330 minutes extended twin engine operations (ETOPS). This reflects how dependable the powerplant will be.
Qantas has been under fire by tabloid media over pressure on pilots to carry only the required legal fuel reserves, after an Airbus A380 diverted to Adelaide on a flight Singapure-Melbourne. Althougth this fact has no relation to engine failures, we believe that the big picture, and it is not a previlege of Qantas, is that economic pressure can make procedures that were exceeding the requirements be abandonned in favor of those that follow exclusively what is necessary and/or required. The problems with the RB211 on the Qantas jets are maybe associated to something “extra” to the maintenance procedures, that was done in its maintenance and overhaul facility in Sidney. These engines now are maintained by a Rolls-Royce shop in Hong-Kong, that for sure carries out everything necessary to keep those engines working reliably, but has not the unique experience of maintaining the engines that are operated by Qantas on its routes and operation procedures.
Australian ATSB, that is investigating the incidents related to the RB211 failures, states that Qantas is bringing its RB211-524G to the latest modification status at shop visits but (in their words) “should the rate of engine failures increase significantly a review of current modification policy will be undertaken”
What do they mean? The current rate is acceptable? It will have to increase significantly for something to be done?
Our view is that the problems should be found AND SOLVED before any increase in the failure rate and before an accident. The failure rate is already too high comparing to other operators (of course not accordingly to Qantas). ATSB should put more pressure in the solution of this problem, before it claims lives.
dowload the article in pdf format clicking HERE
Engineer’s Tool Kit © - http://www.engineerstoolkit.com
Article written on May 2011. No restrictions for non commercial use as long not altered and referencing the source.
Engineer’s Tool Kit assumes no responsibility for the data presented in the article. Information is presented as is. If any copyrighted material is presented here by mistake, please contact for immediate removal.
Photos reproduced from