Black boxes here to stay

	'[Direct streaming] could cause a capacity issue on the networks'
	Dan Pendergast Senior Director for Airline Programmes, Asia-Pacific ARINC

Despite ongoing studies into the potential for aircraft performance data during flight to be directly streamed through satellite links to the ground in real time, most experts agree that traditional black box recording equipment on aircraft will not become redundant. The reason: the high cost of new systems and the massive amounts of data that would have to be transmitted on a continuous basis.

A study jointly conducted by the largest producer of flight data recorders, L-3 Aviation Recorders, and a satellite company, found that even with a 50% reduction in future satellite transmission costs, the price tag for direct streaming would be as much as US$300 million annually for a major airline operating on international routes.

In comparison, data and voice recorders cost about $20,000 and are certified for 100,000 flight hours, or about 30 years.

There is another issue. The failure to recover a black box is very rare. Indeed, only one of L-3’s black boxes has ever been lost after a crash. It was aboard the American Airlines flight that ploughed into the World Trade Centre on September 11, 2001.

“A black box capability will always be needed,” Akhil Sharma, director of air traffic management at SITA, the major aviation communications provider, told Orient Aviation.

“All that we can do is enhance the communications to the aircraft and deliver the infrastructure to get more real time data to supplement that, to provide enough information should the black box be lost.”

Sharma said that like all technologies, black boxes will improve. They will be able to store more information and may even, at some point, be more easily retrievable, or at least “stay alive” for longer after an accident.

The debate about transmission of data from operating aircraft has intensified since Air France Flight 447 disappeared in the Atlantic ocean off Brazil last year. The A330’s black box, the flight data recorder (FDR) and cockpit voice recorder (CVR) have not been found. The only clues to the cause of the accident came from limited data transmitted from the plane through its Aircraft Communications Addressing and Reporting System (ACARS) prior to its disappearance.

	Air France: no signs of black box after A330 plunged into Atlantic

ACARS is an air-to-ground link that automatically sends operational information, maintenance data and fault reports to the ground, but it does not offer the bandwidth needed for real-time transmission of all data stored in the digital FDR and CVR.

Currently, the FDR and CVR serve as onboard recording devices. The FDR collects data from aircraft systems, while the CVR records crew conversation and aural warnings heard on the flight deck. The FDR holds 25 hours of data on up to 88 flight parameters and the CVR stores cockpit audio for between 30 minutes and two hours.

The black boxes are designed to withstand a crash and they emit a locating signal for up to 30 days after an accident or incident. But if they are not found by then, as happened in the case of the Air France jet, the data is unlikely to be recovered.

Experts say direct streaming is technologically possible, but realistically impractical. “My own feeling is it is dependant on determining the amount of data that needs to be down-linked and whether the satellites we use today can support that, keeping in mind that at any one time there must be over 2,000 aircraft flying in the world,” said SITA’s Sharma. “There will be a huge demand on capacity and of course there is the whole issue of cost.”

Dan Pendergast, senior director for airline programmes at ARINC’s Asia-Pacific division, agrees. He said a constant transmission of information would be very expensive. “It is also something the service providers would probably not favour because it could cause a capacity issue on the networks.”

Nevertheless, Pendergast said new technology, such as Inmarsat’s fourth generation I-4 satellites, were adding a significant amount of capacity to networks. These new satellites are used by ARINC’s GLOBALink VDL (VHF Digital Link) network. More than 2,000 aircraft use the network to send over five million messages a month.

It has now been expanded beyond North America and Europe and is available in Asia, at Beijing, Hong Kong, Bangkok, and Singapore.

Sharma said since the Air France tragedy there has been a huge focus on how data links could be used to improve aviation safety. As Europe moves towards a single air traffic control system, authorities there have asked for tenders from groups interested in showing how oceanic tracking and safety efficiency could be improved, based on the use of data link.

Also, Airbus is undertaking a study for improving flight data recovery. This will include, but not be limited to, implementation of extended data transmission from commercial aircraft, so that in the event of accidents, critical flight information could still be recovered and provided to accident investigation authorities, even if finding the black boxes proved futile.

Airbus president and chief executive, Tom Enders, recently said various technical means for reinforcing flight data recovery and data transmission to ground centres were available. “We will now study different options for viable commercial solutions, including those where our experience with real-time data transmission from our own test aircraft could support the further development of such solutions. The study will consider technological issues as well as data protection and privacy concerns,” he said.

There are already systems available that allow some direct streaming. For example, a Canadian company, Calgary-based Western Avionics, offers a system called CommuniCube, which allows automated emergency data streaming. The data transfer can be started through a pilot-initiated “panic” button, or automatically.

In an extreme case, such as the Air France accident, where the pilots might not have the time to activate data transmission, the system can sense sudden changes in aircraft behaviour and begin sending data immediately to an operations centre.

No one now doubts that direct streaming is possible. In fact, many military aircraft already use it. But for commercial airlines, where cost is a far more critical factor in installing such equipment than in military operations, experts are convinced the answer lies in a combination of improved onboard black boxes and an increase in the amount of data that is broadcast to the ground in real time.