Web Exclusive Articles
« back to listing
Shake and break
Image: Emirates’ ‘ICE’ system uses touch-screens, but passengers have been known to ‘interact’ using less ‘suitable’ equipment, such as forks!
There's no great mystery about the workings of an audio/video-on-demand (AVOD) in-flight entertainment (IFE) system. It's a local-area network, in many ways just like those found in millions of offices the world over, with central servers to store data, cables to carry it to where it’s needed, and user terminals with varying degrees of local computing power. But there the resemblance ends, and the differences between the cabin and office environments can pose some of the biggest serviceability and maintenance problems known to aircraft operators.
Take the type and volume of data flowing round the system. The typical office network has to handle fairly infrequent demands from a few dozen people for kilobit-sized documents and pictures and presentations running to a few megabits. The cabin network, by contrast, can be hit by constantly shifting demands from two or three hundred passengers for megabits per second of streaming video.
Then there are the users themselves. Office workers are there to work, in a generally disciplined and focused way with familiar equipment and software. The occupants of an airline cabin can range in age from nine to ninety, in IT proficiency from complete familiarity to utter ignorance, and in mood from fairly relaxed and cheerful to anxious, confused and even angry.
And finally there’s the real battlefront – the passenger-facing equipment. The stories of passengers using forks to operate touch-screens are no urban myth, according to the system manufacturers who have to pick up the pieces. As for the underseat boxes used to house processing and power for the screens in each seat row, one vendor says it all: “There will always be problems as long as sensitive electronic units are installed at floor level – how long would your laptop last if you constantly kicked it around your living room?”
This is the environment in which the system suppliers and their support organisations strive daily to achieve the 99%+ seat availability targets imposed by airlines all too conscious of the business-losing potential of IFE failures. Among those leading the charge for ever higher levels of reliability are top two vendors Panasonic and Thales, promising newcomer Lumexis, and Montreal-based IFE installations specialist, Inflight Canada.
Image: IFE system users cover the full age range – pity the parents of any child confronted by an IFE system failure during a long flight!
Over the years the manufacturers have put huge amounts of money into developing their designs and product support systems. Have their efforts paid off by improving performance in terms of seat availability, the industry-standard benchmark?
“There has been a clear progression in reliability from one generation of our product to the next,” says Panasonic product marketing director Cedric Rhoads. “Our first distributed system initially operated at 85% seat availability. That was unacceptable and since then we’ve worked on improving performance to the point where today’s eX2 consistently achieves 99% and often exceeds 99.5%. Our goal now is to achieve 99.95%.”
Thales came later to the IFE market but has recently begun to challenge Panasonic for leadership of the AVOD sector. Based in Irvine, California, it claims a current seat availability figure of 99.9% for its TopSeries range, having laboured at 92-93% in the early days of the system’s career.
These numbers have been achieved against a background of ever-increasing system complexity and customer expectation, points out Thales’ chief engineer, Ken Brady. “For example, when IFE systems were based on videotape, the quality of the tapes was never a measurable element of reliability. Now some airlines monitor parameters such as the quality and integrity of the encoding of MPEG video files.”
The bar has been raised in other areas too. A typical content offering has expanded from nine tapes to as much as 500 video programmes, while the systems are also expected to deliver power for passenger devices, live satellite television and air-to-ground connectivity. “The number of chances for things to go wrong has grown by orders of magnitude,” says Brady. “So it’s rather remarkable that we should appear to have maintained or improved our reliability performance.”
Appearances are everything, however, and even an average 99.9% seat availability figure can leave room for the occasional visible and embarrassing failure. Doug Cline is the chief executive of Californian company Lumexis, which recently announced that it had secured a launch customer for its Fibre To The Screen (FTTS) fibre optic-based system and planned to start its first operational installations next year.
“On a recent round trip between Los Angeles and Hong Kong the IFE worked well outbound but went ‘dark’, without any video, for ten hours on the return flight,” he reports. “I think there can sometimes be a significant disconnect between reported availability and the reality faced by passengers and cabin staff.”
Track and trace
Such incidents are bad news for vendor and airline alike, and there can be no question of the willingness of the big two manufacturers to go many extra miles to eliminate them.
“We constantly monitor our installed base, either directly or through systems such as our Online Maintenance Tool (OMT) and Data Analysis and Reliability Tracker (DART), to spot performance problems and trends so we can drive down software and hardware-induced failures,” says Panasonic’s Rhoads. “Our support engineers work closely with customers and conduct ‘fly-alongs’ to observe system performance directly. In our reliability lab we carry out highly accelerated life and stress testing of every new design. And we analyse new core technologies for their potential to improve reliability.”
The drive for tighter integration of IFE into seats, as exemplified by Panasonic’s new Fusion initiative, could bode well for reliability. “We’re now using LED backlights in place of the previously standard compact fluorescent lightbulbs (CFLs) in all our new screens, including the Fusion Integrated Smart Monitor,” says Rhoads. “LEDs offer better overall reliability as well as consistent light output over their lifespan, whereas CFL output declines with time, often necessitating replacement before an actual failure. The Fusion screen will also feature a new low-power architecture, reduced complexity and a lower component count, all of which should further benefit reliability.”
Thales also seeks continuous improvements in reliability, focusing in particular on three design principles – fault tolerance, minimal component counts, and redundancy in the passenger controls – with the aim of maintaining the level of service to the passenger in the face of component failures.
“The first interactive version of TopSeries was designed to tolerate a server failure,” says Brady. “The most recent versions are fully redundant to the seat-group, and one is fully redundant to the seat. So full service is maintained even in the event of failure of key components such as servers or intermediate network switches.”
He continues: “The fewer the parts, the fewer the opportunities for failure. So we continuously architect simpler systems with fewer components, while not compromising on functionality and redundancy. And at the seat we can provide both a passenger control unit (PCU) and a touch-screen, both of which can be used for any of the available functions.”
While Thales and Panasonic currently dominate the AVOD market, new entrants like Lumexis are knocking insistently at the door, and they believe that only a revolution in system design will settle the reliability question once and for all. “Most of the systems now in service were conceived in the 1990s and have been the subject of subsequent upgrades that have left the underlying architecture untouched,” asserts Doug Cline of Lumexis. “Attempting to wring every last bit of performance out of complex, ageing hardware and software means that they remain susceptible to multiple modes of failure.”
Compared with conventional systems, with their zone and seat boxes and seat-to-seat cables, Lumexis’ FTTS is very pared-down indeed. At the head end, one 4MCU, 13 lb Switch Server Unit (SSU) can feed content via 24 fibre optic cables direct to 24 screens – there are no zone boxes and no space-stealing seat boxes. Screen power, which conventionally resides in seat boxes, is tucked away, safe from kicks, spillages and overheating, beneath the floor.
Lumexis recently concluded an in-service trial of FTTS aboard a US Airways Airbus A320. “We experienced no head-end failures and never once had to reset the system in nearly 300 flights,” says Cline. “That’s an unprecedented level of performance compared with earlier-generation systems.”
Image: Inflight Canada’s iCACHE moves vulnerable seat boxes into a dedicated underfloor storage compartment
As well as designing the FTTS installation, Inflight Canada has for several years championed the elimination of seat boxes by shifting their contents to its iCACHE underfloor recesses. This, says company president George Smallhorn, is fundamental to improvements in IFE reliability. “No matter how robust the head end or how sound the software, there will always be problems in the cabin and at the seats as long as processors are housed in boxes on the floor,” he declares.
iCACHE has been selected by Air Canada, American Airlines and Virgin America and implemented in well over 200 aircraft. “No iCACHE-housed units have been removed from any of these aircraft as a result of failure for environmental reasons,” says Smallhorn. “There are aircraft among these fleets that still have seat boxes, however, and they continue to suffer failures.”
Two recent technological initiatives – the advent of fibre optic cable, and the ultimately abandoned efforts to produce wireless IFE systems for the Boeing 787 – could have important implications for reliability. The industry appears divided on the first but in broad agreement on the second.
Inflight Canada designed a method of installing fibre optic for Lumexis that minimised the chances of damage to the cable while modification work was in progress. In preparation for the US Airways trial, the company sent a team to a Canadian Forces base to observe how the military install fibre optic in combat aircraft. “All work on the aircraft was stopped while fibre optic installation was going on,” says Smallhorn. “But the words ‘stop’ or even ‘slow down’ don’t exist in the air transport world. So we had to come up with a way of completing the modification of the aircraft while simultaneously installing the fibre optic.”
The result is a new version of iCACHE incorporating special routing rails that allow the cables to be quickly laid in place and then secured by means of a cushion clamp with a quick-release lock. “That allowed us to safely adjust the longitudinal location of each seat fibre optic run in relation to the transverse beams,” says Smallhorn. “It saved hundreds of man-hours and protected the fibre optic throughout. In the end, fibre optic is really not all that fragile.”
Doug Cline is equally emphatic: “In the US Airways flight trial there wasn’t a single problem with the cable during installation and operation,” he says. “I’m sure that all the manufacturers and airlines will move to fibre optic before long. It’s absolutely superior in terms of data capacity, and now we’ve proved it’s extremely durable in daily airline operation.”
The big two are more cautious, however. “We’ve used fibre optic in our products since December 2007 and it’s proved to be quite reliable in service,” says Panasonic’s Rhoads. “But it does require special maintenance techniques, and things can get complicated when termination points are damaged. Our applications are behind the scenes, well away from the cabin and its challenges, and have been very reliable as long as the maintenance rules are obeyed. But the jury’s still out on the long-term reliability of fibre optic in the cabin.”
Thales also keeps fibre optic far from the madding crowd. “We generally confine fibre optic to applications behind the walls, safe from potential access or abuse in the cabin,” says Brady. “And the use of these cables certainly does raise maintenance concerns: special cleaning procedures are needed when making connections, and terminating the cables is a highly specialised skill.”
One of the features of the Boeing 787’s troubled development was a dash to develop wireless IFE systems in order to save weight and facilitate cabin reconfiguration. In the end the savings proved to be negligible and the idea was dropped. But the idea is now back on the table in connection with projects like Bombardier’s CSeries. If wireless IFE does come to fruition, will it be any more reliable than today’s systems?
“On the face of it, wireless would be more reliable because the wire runs for data would be eliminated,” says Rhoads. “However, for various reasons, problems with data wiring are increasingly rare. And in the whole wireless debate it tends to be forgotten that you still need wires to distribute power, so that source of potential failures won’t go away.”
Brady has his reservations about the very concept of wireless for IFE content distribution. “Wireless networks are great when they work,” he points out. “But when they don’t, they’re not easy to troubleshoot. For instance, wireless is subject to interference not only from other devices but also from the movement of passengers and staff around the cabin. Maintenance personnel whose training has been focused on resistance measurements on wires may find wireless networks much more difficult to handle.”
Top-quality IFE is a key weapon in the airlines’ struggle for commercial survival. Their customers have come to see it as a fundamental right. And the suppliers face ever-rising expectations of system reliability, even as extra complexity arrives in the form of new functions like connectivity and in-seat power. In this arena of moving targets, one thing can truly be counted on – reliability will be a hot topic for years to come.
Brendan Gallagher is an expert IFE writer and commentator who has followed the subject for the last 20 years – he began his career in IFE/communications in the late 1980s with Inmarsat.
This article was first published in Aircraft Interiors International 2010 Showcase
29 May 2010