Software takes main stage in efforts to improve 787-8's reliability, as 787-9 and -10 progress
It is easier for to be upbeat about the 787 these days. The Dubai Airshow saw the program pass the 1,000-order milestone in record time for a twin-aisle program, on the back of a large order from for the 787-10, while flight tests of the continue to accelerate with the introduction of a third aircraft to the certification effort.
Yet overshadowing the brighter promise of the mid- to long-term future is the urgent challenge of improving the troubled 787-8's in-service reliability levels. The task is proving more complex and frustrating than Boeing had imagined, and at Dubai the manufacturer conceded that overall performance is now not expected to reach that of the 777 until sometime before mid-2014.
Boeing Commercial Sales Vice President Marty Bentrott says some operators such ashave experienced “some early teething problems,” and seen “reliability issues with some components.” The company is “committed to resolve those problems. We are making good progress but 'do we have additional work ahead of us?' Yes.” Bentrott says the company estimates that it will be “another six months or so” until the 787 reaches “the reliability rate of the 777.”
Boeing has been battling for improved reliability rates on the aircraft since it began suffering system and component glitches shortly after entering service in late 2011. Although the process was interrupted during the prolonged grounding of the fleet in the wake of the battery issues in early 2013, the recovery initiative was stepped up as teething issues persisted. Earlier this month Boeing disclosed that, along with measures to boost the reliability of some components, it is also developing software improvements to reduce the number of nuisance warnings and improve the robustness of the aircraft's self-diagnostic or built-in-test equipment capability.
The process involves simplifying some of the software that runs in the 787's avionics system. Revised software loads are expected to be installed in the fleet by the end of the year, with some of the changes being tested on the 787-9. The 787's software-intensive control and monitoring systems measure vast amounts of data, far more than any previous airliner, and this has triggered an unexpectedly high number of low-level alerts that have led to inadvertent higher-level events, turn-backs and diversions. The aircraft has been internally dubbed by Boeing as a systems “hypochondriac,” flagging notices to flight crews who generally react by erring on the side of caution. “We are looking at software improvements to reduce the number of nuisance warnings and improve the built-in-test equipment capability,” says 787 Airplane Development Vice President Mark Jenks.
Although Jenks is keen to point out that Boeing is not trying to “dumb down” the software, “we're doing things to simplify it. The 787 system has more data than it needs—it's a very smart airplane. So we are fine-tuning that in some areas.” The process is being dovetailed with flight tests of the 787-9, with simplified loads flying on the initial test aircraft. In addition, results from investigations into system call-outs or '“squawks” from the heavily instrumented 787-9 test aircraft are being rolled back into the software update. Revised software loads are being prepared for installation throughout the fleet, with operators such asexpected to begin updating aircraft in December.
Commenting recently on the focus on improving the software, Boeing President and CEO Jim McNerney says “improving dispatch reliability of the 787 is one of our top priorities. We are not satisfied with the fleet-wide performance, even though it is at 97% on average. There are some customers who are not at that level and we're not pleased about that. We still have more work to do and while we are otherwise pleased with feedback in areas like fuel burn, we will not be satisfied until we meet customer expectations across the board.” McNerney says ironing out issues with the software heavy is a key priority. “Old messaging (in the software) is roughly one-third of the issue. It's frustrating for us and very frustrating for our customers. It's an all-hands-on-deck effort. We want to get everyone higher but when you add it all up there's been a steady improvement.”
is another of the early 787 operators affected by the issues. LAN Vice President Engineering and Maintenance Sebastian Acuto says grounding of the 787 “has affected the learning curve for everybody.” He acknowledges that while reliability has already improved “quite significantly, we are still not where we want it to be.” According to Acuto, the average dispatch reliability for the total in-service 787 fleet is at 97.5% and LAN's fleet is at 97.1%. That compares to a dispatch reliability target set by Boeing of 99.2% two years after entry into service. “It is going to take a little bit longer” to reach that, Acuto says.
LAN is working with Boeing to eliminate the root causes and “the great majority of the root causes, are already identified,” he explains. Both are now working on implementing modifications. The issues faced by LAN have been changing, and Acuto sees that as “good news” as it shows that Boeing has been able to eliminate some of them.
However, there are recurring problems affecting the flight control system and the air conditioning. Very often the system is showing messages that crews have to deal with on the ground prior to departure. “Most of the time there is nothing behind it, but you still have to deal with it,” Acuto says. He believes that the solution is “a combination of hardware and software, but a lot of it has to do with upgrading the software.” LAN's challenge is not made any easier by the fact that the airline is starting to deploy the aircraft to more stations and is now flying the Santiago-New York and the Santiago-Madrid-Frankfurt routes.
Structurally and from most of the systems' perspective, the experience is better, says Jenks. “Structures, ducting, tubing and so forth have performed very well. We've had severe lightning strikes and vehicles have hit the fuselage, and fundamentally the structure has worked out phenomenally well. We are getting fewer 'ramp rash' [collisions and damage from ground vehicles and servicing trucks] issues than we expected.” However, increasing the robustness of some areas, particularly electric components, remains a key focus, says Jenks. “There are more of these issues than we want, and we are very energized to fix it. But none of them are things that would have us rethinking the fundamental architecture. The bottom line is it is not flawed and it is working well.”
Many of the improvements will roll straight into the development of the 787-10, Jenks notes. “With the -10 we are up and running. It is fortunate now, because the timing allows us to transfer many of the team working on the -9 to the -10. Lots of the team learned the initial lessons on the -8, and the -10 is fundamentally a much simpler job. That's the beauty of it.” With systems, weight and overall technology derived straight from the -8 and perfected on the -9, the -10 is “just a simple stretch,” he adds. “It's all about maximizing commonality.” The airframe will be stretched by a further 18 ft. in length over the -9 and the overall configuration has already been essentially firmed up, Jenks says.
Flight tests of the 787-9 meanwhile stepped up to a new rate on Nov. 19 when the third 787-9, ZB021, joined the certification program. The aircraft is the first-1B-powered 787-9 and enters flight test on the heels of ZB002, the second Rolls-powered aircraft, which began tests on Nov. 7. The third 787-9 will be used for low-speed aerodynamic performance work, as well as brake, flutter and -related propulsion performance testing. The second aircraft is targeted at autoland, avionics, fuels and propulsion tests, as well as evaluation of the environmental control and nitrogen-generating systems. By mid-November the test fleet was quickly approaching more than 200 flight hours and more than 65 flights since the start of tests on Sept, 17. The -9 derivative is 20 ft. longer overall than the baseline 787-8, and will be available with either the newly-certificated “Package C” version of the or the upgraded “PIP II” variant of the General Electric GEnx-1B.