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On March 12th, I had written about the "urgent" safety recommendations by the US National Transportation Safety Board (NTSB) regarding the Rolls Royce Trent 800 RB211 engines which are used by many Boeing 777 operators. It is estimated that there are currently about 220 Boeing 777s powered by Rolls-Royce Trent 800 engines in operation with 11 airlines around the world.

The list includes Air New Zealand, British Airways, American Airlines, Cathay Pacific, Delta Airlines, El Al, Emirates, Kenya Airways, Malaysia Airlines, Singapore Airlines, and Thai Airways.

Image courtesy Singapore Airlines

I was concerned about the impact on my favourite, Singapore Airlines (SIA), who with 77 aircraft, happens to be the world largest operator of Boeing 777s. The 777 makes up more than 75 per cent of Singapore Airlines' fleet (77 777s out of a fleet of 101 aircraft), and this will only grow as more join their fleet, and the 14 venerable Megatop Boeing 747-400s are retired from service by next year.

SIA has 58 Boeing 777s, that are powered by Rolls-Royce Trent 800 engines. These are the 31 Boeing 777-200 (Trent 884), 15 777-200ER (Extended Range), and 12 777-300 (both Trent 892) models. 19 are 777-300ER (also called 77W) powered by General Electric GE90-115B engines, and which are used primarily in long haul flights.

I wrote to Stephen Forshaw the spokesperson for Singapore Airlines with my concerns. He has assured me and all passengers of Singapore Airlines of the airline's confidence in the Rolls Royce Trent 800 engines powering their fleet, and the short-term fix addressed by the NTSB, with training and procedures mandated the US Federal Aviation Administration (FAA), and the European Aviation Safety Agency (EASA) minimise the risk while engine manufacturer Rolls Royce rolls out the re-designed Fuel Oil Heat Exchanger (FOHE) as a longer term and more permanent solution.

He also clarified in depth about the routes that Singapore Airlines flies which are more tropical in nature when compared to the extended polar routes flown by some other airlines.

I posed to him that even Singapore Airlines flights flies polar routes. and "with the -40 Deg and colder temperatures experienced at high altitude the route really does not have an impact on the potential for icing. i.e. whether it is a polar or tropical route."?

Stephen Forshaw explains

You are correct that temperatures can reach -40 or lower at cruise altitude, whether in the tropics or the polar region. That is not really the concern. As you would be aware, jet fuel has a very low freezing point - the variety used for commercial aircraft is Jet A1 and has a freezing point of -47 degrees Celsius. Sometimes, the temperature outside the aircraft will reach below that point, but the fuel tank ambient temperature is always higher than the outside temperature, and this prevents fuel from freezing.

Where icing potentially occurs is where the fuel has prolonged exposure to temperatures outside the aircraft at the more extreme end. [In] the BA [British Airways] case, outside temperatures for much of the polar journey reportedly reached as low as -70 degrees. The concern is the prolonged exposure to excessively low temperatures.

What is meant by my comment on the tropical nature of our operations is that, while the aircraft is on the ground, the ambient temperature very quickly warms up to a point well above zero degrees and will quickly melt any ice particles that may form. The difficulty in the BA case was that the ground temperature in Beijing was still well below zero for the entire time the aircraft was in transit. With a small number of exceptions, our RR [Rolls Royce] powered 777s tend not to operate to points where they are likely to face prolonged exposure to extreme cold conditions, both in cruise and on ground.

It would seem, from the available reports, that there were a set of circumstances that contributed to this accident; not merely that the temperature was low. Low temperatures are nothing new for jet fuel systems; it is the prolonged exposure and lack of understanding at that time of the remedial actions that we know are now necessary that are learning points. These points have all been incorporated into our procedures and pilot training, and our pilots are well aware of the issues.

In response to my query "has any SQ B777 flight experienced an in-flight un-commanded engine roll back ?" He said

We have not experienced any similar incident, and this is possibly because, as I said, our RR-powered 777s tend not to be operating in the prolonged extreme cold conditions that the BA flight experienced. Those of our aircraft operations with prolonged exposure to polar routes are only using the B777-300ER (GE-powered) and A340-500 (RR powered but with a different fuel flow system).

To clarify, the A340-500 series used on the non-stop Singapore Los Angeles and Singapore New York service are powered by the Rolls Royce Trent 553 engines. Having flown these flights right from their inaugural, I can attest to their reliability.


In response to my queries "on the "mood" of the airline about the Boeing 777 powered by the Rolls Royce Trent 800 RB211 engines, the fix that is being planned, and whether the recent developments will have any impact on SQs decisions on the engines for future B777 purchases ?" Stephen replied

The 777 will remain an integral part of our fleet operations for many years to come. It is an exceptionally good aircraft with a high level of reliability and customer appeal. We don't see that changing as a result of this finding, because (a) the fix developed has already been rolled out through training and procedures, and (b) RR is engaged on a longer-term redesign. I want to be clear on your question about 18 months as a time to fly with these "risks"- if there were no other mitigation measures, that would be a concern, but the procedures jointly developed and approved by the FAA and EASA provide a solution in the meantime to minimise the risk while the longer-term R&D work is done by RR.

Stephen Forshaw also confirmed that the recent developments will have no impact on the plans of Singapore Airlines to phase-out of the Boeing 744-400s by early next year.

This issue will not affect our plans to retire the B744s from service - that is a wholly different question and contingent on deliveries of newer, more fuel-efficient aircraft such as the A380 and B777-300ER.

It is clear that while the short-term training and procedural fix recommended by the NTSB, FAA and EASA is acceptable for now, it is surely not acceptable for the long term. By then Rolls Royce will have implemented the re-designed FOHE.

Would I fly aboard a Rolls Royce Trent 800 powered Boeing 777 of Singapore Airlines -- ABSOLUTELY!!!!!!!

On a side note, with the phase-out of the B744s, Singapore Airlines' long association with US engine manufacturer Pratt & Whitney will come to an end, as their entire fleet from the mighty Airbus A380 to the Boeing 777s to the Airbus A330 will be powered by Rolls Royce and General Electric engines. At one point about 10 years ago, Singapore Airlines was PWs largest customer in Asia. Singapore Airlines Cargo though, will continue using the PW4056 powered B744s.

and finally .... Stephen Forshaw is leaving Singapore Airlines for other career prospects. I wish him all success. His successor Nicholas Ionides who takes over as Vice President Public Affairs, with effect from 4 May 2009 is well known in the blogosphere. Mr Ionides, 37, is currently the Singapore-based Managing Editor (Asia) at Reed Business Information, publishers of Flight International and Airline Business Magazines and the Air Transport Intelligence and Flightglobal news websites

Following two engine thrust rollback events on Boeing 777 aircraft powered by Rolls-Royce engines, the United States National Transportation Safety Board (NTSB) issued an urgent safety recommendation today calling for the redesign of a Rolls- Royce engine component.

The Safety Board also recommended that, after the redesign is completed, the new system be installed on all affected B-777 airplanes at the next maintenance check or within six months.

These recommendations are being issued in response to the findings in two investigations, one accident and one incident, involving engine thrust rollbacks on Boeing 777-200ER airplanes powered by the Rolls-Royce RB211 Trent 800 Series engines.

In both cases a build-up of ice (from water normally present in all jet fuel) on the fuel/oil heat exchanger (FOHE) restricted the flow of fuel to the engine, resulting in an un-commanded engine rollback.

The first event, which is still being investigated by the UK's Air Accidents Investigation Branch (AAIB), occurred on January 17, 2008, when a British Airways Boeing 777 experienced a dual engine rollback on final approach and crashed short of the runway at London's Heathrow International Airport. One passenger was seriously injured, eight passengers and four of the flight crew sustained minor injuries; the airplane was substantially damaged.

The second event occurred on November 26, 2008, when a Delta Air Lines Boeing 777 experienced a single engine rollback during cruise flight over Montana while en route from Shanghai to Atlanta. Normal operations resumed after the flight crew followed Boeing's published procedure to recover engine performance; the airplane landed safely in Atlanta.

Testing in support of the UK accident investigation led Boeing to develop procedures to help prevent ice accumulation, and to recover thrust in cases of ice blockage. As more information from the Delta rollback event was developed, Boeing modified the procedures, which became the basis of an airworthiness directive issued by the Federal Aviation Administration.

While the procedures may reduce the risk of a rollback in one or both engines due to FOHE ice blockage, they add complexity to flight crew operations, and the level of risk reduction is not well established. And because the recovery procedure requires a descent, the aircraft may be exposed to other risks such as rising terrain or hazardous weather, or the inability to achieve maximum thrust during a critical phase of flight, such as during a missed approach.

Because of these hazards, the Safety Board has determined that the only acceptable solution to this safety vulnerability is a redesigned FOHE that would eliminate the potential of ice build-up. On February 23, 2009, Rolls-Royce indicated that a redesign of the FOHE was underway, and that they anticipated the redesign to be tested, certified and ready for installation within 12 months.

NTSB Acting Chairman Mark V. Rosenker said

"With two of these rollback events occurring within a year, we believe that there is a high probability of something similar happening again," "We are encouraged to see that Rolls-Royce is already working on a redesign, and we are confident that with the FAA and EASA (European Aviation Safety Agency) overseeing the process, this flight safety issue - even one as complex as this - will be successfully and expeditiously resolved."

The NTSB has made the following two recommendations to both the Federal Aviation Administration and the European Aviation Safety Agency:

• Require that Rolls-Royce redesign the RB211 Trent 800 series engine fuel/oil heat exchanger (FOHE) such that ice accumulation on the face of the FOHE will not restrict fuel flow to the extent that the ability to achieve commanded thrust is reduced.
• Once the fuel/oil heat exchanger (FOHE) is redesigned and approved by certification authorities, require that operators of Boeing 777-200 airplanes powered by Rolls Royce RB211 Trent 800 series engines install the redesigned FOHE at the next scheduled maintenance opportunity or within 6 months after the revised FOHE design has been certificated, whichever comes first.

Download copies of the safety recommendation letter :

• to the Federal Aviation Administration
• European Aviation Safety Agency

The much publicised bio-fuel test flight of Air New Zealand was conducted successfully. Congratulations to the teams at Air New Zealand, Boeing, Rolls Royce, and UOP division of Honeywell.

The blend of fuel was 50% Jet A-1, and 50% Jatropha oil. The Jatropha plant is grown extensively in India, and bio-diesel is slowly inching its way in to the market. I have opined before, that airlines in India, who are constantly complaining about the cost of fuel should strongly consider the bio-fuel option.

While there are many stories on the flight, I found George Raine's article at the San Francisco Chronicle, and Kris Hall's article at The Dominion Post, the most comprehensive technically.

More details can be found at Air New Zealand's website.

TV NZ has an article along with a video report, which I reproduce below as a convenience to Bangalore Aviation readers.

Read more articles on biofuel at Bangalore Aviation.

Airbus A330-343E, F-WWKZ, CN 978, pictured here in the cold grey skies of Toulouse, France, will soon be heading to the lush tropical city-state of Singapore, as 9V-STA, and joining the fleet of Singapore Airlines, who will become the newest operator of the Airbus A330 aircraft.

Singapore Airlines will introduce its new Airbus A330-300, powered by Rolls Royce Trent 700 engines, in a mid-range regional aircraft, positioning, replacing the existing Boeing B777's, on routes to Australian and Japanese cities, progressively from end March 2009.

SQ A330 Seat Map
The aircraft will be configured with 285 seats in a two class configuration. 30 Raffles Class (Business Class) in a 2-2-2 abreast layout, and 255 in a 2-4-2 layout. The new cabin features will be revealed in January, but the aircraft does feature a new Business Class seat, specially designed for regional and medium-haul flights. All seats will feature the new KrisWorld, Singapore Airlines award-winning in-flight entertainment system.

The first of 19 new A330-300s will be delivered to Singapore Airlines by Airbus in mid-January. Initially, the aircraft will be used to complete pilot conversion, and thereafter, operate some short sectors between Singapore and Kuala Lumpur, and Singapore and Jakarta, during late February and March, to fine tune the crews and operations, but these cities will not continue with the A330's.

Singapore Airlines will use the A330's initially to select Australian cities (Brisbane, Perth, Adelaide) and then add Japan (Nagoya and Osaka).

Singapore Airlines will induct the A330's into commercial service on March 30, 2009, with an inaugural service to Brisbane, which marks the 25th anniversary of the commencement of Singapore Airlines services between Singapore and Brisbane.

The planned deployment of the A330-300 is:

End March 2009
Brisbane, SQ245/246, SQ235/236, daily
Brisbane, SQ255/256, 5 flights per week

April 2009
Perth, SQ224/225, 5 fights per week

May 2009
Perth, SQ223/226, SQ215/216, daily

June 2009
Adelaide, SQ268/269, daily
Nagoya, SQ671/672, daily

Then a long break till March 2010
Osaka, SQ617/618, daily

For more information visit the Singapore Airlines website.

Photo courtesy Wikipedia
Air New Zealand and Boeing [NYSE: BA] announced Dec. 3 as the date for the airline's sustainable biofuels flight from Auckland using a 747-400 jetliner. Conducted in partnership with Rolls-Royce and UOP, a Honeywell company, one of the airplane's four Rolls-Royce RB211 engines will be powered in part using advanced generation biofuels derived from jatropha. Air New Zealand now becomes the first airline to use a commercially viable biofuel sourced using sustainability best practices.

Boeing, Air New Zealand and UOP have worked diligently with growers and project developer Terasol Energy to identify sustainable jatropha in adequate quantities to conduct thorough preflight testing. Using proprietary UOP fuel processing technology, the jatropha crude oil was successfully converted to biojet fuel, marking the world's first large-scale production run of a commercially viable and sustainable biofuel for aviation use.

"This flight strongly supports our efforts to be the world's most environmentally responsible airline," said Air New Zealand Chief Executive Officer Rob Fyfe. "We recently demonstrated the fuel and environmental gains that can be achieved through advanced operational procedures using Boeing 777s. We're also modernizing our fleet as we await our Trent 1000-powered 787-9 Dreamliners, which will burn 20 percent less fuel than the planes they replace. Introducing a new generation of sustainable fuels is the next logical step in our efforts to further save fuel and reduce aircraft emissions."

As part of the fuel verification process, UK-based engine maker Rolls-Royce's technical team conducted extensive laboratory testing to ensure compatibility with today's jet engine components and to validate the fuel meets stringent performance criteria for aviation fuel.

"In preparation for Air New Zealand's test flight we achieved our near-term goal - identifying and sourcing the first large-scale run of sustainable biofuel for commercial aviation," said Boeing Commercial Airplane's Managing Director of Environmental Strategy Billy Glover. "The processing technology exists today, and based on results we've seen, it's highly encouraging that this fuel not only met but exceeded three key criteria for the next generation of jet fuel: higher than expected jet fuel yields, very low freeze point and good energy density," Glover explained. "That tells us we're on the right path to certification and commercial availability."

Because of the unique environment in which aviation operates, stringent criteria are in place to ensure that any alternative fuel meets or exceeds current jet fuel requirements. Advance testing for the Air New Zealand flight showed that the jatropha-based biofuel met all critical specifications, including a freeze point at -53 degrees Fahrenheit (-47 degrees Celsius) and a flash point at 100 degrees Fahrenheit (38 degrees Celsius).

"Laboratory testing showed the final blend had excellent properties, meeting and in many cases exceeding the stringent technical requirements for fuels used in civil and defense aircraft," said Chris Lewis, Rolls-Royce company specialist for fuels. "The blended fuel therefore meets the essential requirement of being a 'drop-in' fuel, meaning its properties will be virtually indistinguishable from conventional fuel, Jet A1, which is used in commercial aviation today."

To process the jatropha crude, the team relied on UOP's green jet fuel processing technology based on hydroprocessing methodologies that are commonly used to produce transportation fuels. During processing, hydrogen is added to remove oxygen from the biomass, resulting in a bio-derived jet fuel that can be used as a petroleum replacement for commercial aviation. Boeing is working with airlines and engine manufacturers to gather biofuel performance data as part of the industry's efforts to revise the current American Society for Testing and Materials (ASTM) standards to include fuels from sustainable plant sources. Jatropha, which can be grown in a broad range of conditions, produces seeds that contain inedible lipid oil that is extracted and used to produce fuel. Each seed produces 30 to 40 percent of its mass in oil. Plant oil used to create the fuel for the Air New Zealand flight was sourced from nonarable lands in India and Southeastern Africa (Malawi, Mozambique and Tanzania).

Air New Zealand is one of several air carriers working to diversify and secure its energy future through participation in the Sustainable Aviation Fuel Users Group. That effort includes a commitment to sustainability criteria for fuel sourcing and commercializing plant-based fuels that perform as well as, or better than, kerosene-based fuel but with a smaller carbon lifecycle. The goal is to create a portfolio of next-generation biofuels that can be blended with traditional kerosene fuel (Jet A) to improve environmental performance.

Additional flight specifics will be announced closer to the actual flight date.