Dubai Air Show

TopFlight SDU tailored to fit single-aisle and regional aircraft

 - November 6, 2007, 7:16 AM

The new TopFlight satellite data unit (SDU) from Thales is small, light and affordable enough to bring satellite communications to single-aisle and regional airliners.

According to Christophe Picco, Thales Aerospace communication, navigation, surveillance strategy manager, the imminent launch of the Inmarsat SwiftBroadband service with its 432-kbps data rate “breaks one of the last barriers to communications on aircraft” by enabling passengers and crew to communicate using the Internet or customers’ own devices.

Traditional satellite communications services rely on multiple avionics boxes whose size, weight and price make them impractical for many aircraft, Picco said. The TopFlight SDU, though, was designed in accordance with the Arinc 781 standard for Mark 3 aviation satellite communications systems. Approved and promulgated last year, the new standard was developed with SwiftBroadband in mind.

The new SDU is designed to deliver all available services, Picco said. They include air traffic control and airline operations control (AOC) communications, along with new SwiftBroadband cockpit services–such as weather map downloads–and connectivity in the cabin. The result is a single 6-MCU box weighing less than 25 pounds and including a 30-watt high-power amplifier that replaces three boxes occupying between two and four times that volume, enabling it to fit any single-aisle, regional or business jet.

Antennas, too, have shrunk. The high-gain antennas needed for worldwide communications using previous generations of Inmarsat satellites typically are housed in fairings 20 inches wide, 67 inches long and five inches high.
New-generation antennas, such as the EMS AMT-300, are only one third the weight and require a fairing just two inches high, so they do not produce nearly as much drag.

The new avionics are much more versatile. As well as providing classic cockpit and cabin communications, they work with electronic flight bags (EFBs), providing the capability to connect the EFB in cockpit with AOC on the ground to retrieve graphical weather and provide access to Web-based operations and maintenance material.

In the cabin, with the addition of a WiFi access point, they can support wireless services, including voice-over-Internet protocol (VoIP). And they support the pico cells about to be introduced to enable passengers to use their own GSM cell phones.

In fact, the Thales SDU has been specified as part of the hardware system Kid Systeme is designing for the SITA/Airbus OnAir system. “There have been a lot of discussions about GSM in airplanes,” Picco commented. “With this unit the airline can choose whether to allow voice calls.” Testing this year will help evaluate passenger reactions.

OnAir calls should cost $2.50 per minute outgoing and $2.30 per minute incoming. Text messages using the SMS service would cost $0.50 to send and nothing to receive. Prices for the AeroMobile cell phone service are significantly higher at $3.50 per minute for outgoing calls and $1 per SMS because that system does not use SwiftBroadband.

An undisclosed business aircraft manufacturer has selected the TopFlight SDU to provide WiFi and VoIP connectivity, and low-cost airline Ryanair plans to equip its whole fleet.

The current SDU provides two channels to support GSM and Internet access. By the first quarter of next year it is to add two more channels for cockpit use, and by the third quarter of 2009, Thales plans a 5/6-channel version with an external 60-watt high-power amplifier that will provide two voice and one classic data channel plus two channels of SwiftBroadband all operating simultaneously.

“That’s the maximum configuration you could imagine for a large aircraft,” Picco said, since Inmarsat has limited each aircraft to two SwiftBroadband channels for the time being. “By 2010 or 2011 we should be able to go to more channels, but it’s forbidden for now.”