Announcing its agreement with Airbus yesterday, satellite communications provider Inmarsat – long known for its important communications role in the Maritime Global Distress and Safety System and in providing many kinds of safety-critical aeronautical communications – claimed its new SB-S system would provide “a paradigm shift in aviation safety and efficiency”.
An Internet Protocol-based (IP) broadband communications platform, SB-S will operate through five of Inmarsat’s geostationary communications satellites.
Today these SB-S-capable satellites include three fourth-generation I-4 satellites launched from 2005 to 2008 and Alphasat, the larger and more payload-capable Inmarsat I-4A F4 satellite launched on July 25, 2013, plus one other. Together this constellation of satellites carries Inmarsat’s Broadband Global Area Network (BGAN).
However, beginning around 2021, Inmarsat will start transitioning BGAN and its SB-S service from the I-4 constellation to a new generation of much more capable broadband communications satellites. This will be its planned I-6 constellation, the first satellite in which is slated for launch in 2021.
Capt. Mary McMillan, Inmarsat Aviation’s VP safety and operational services, told MRO Network Daily that, using a dedicated, secure flight-deck communications channel handling automatic dependent surveillance - contract (ADS-C), ACARS over IP and controller-pilot data link communication (CPDLC) messaging, SB-S will allow users to “continuously flight track” aircraft throughout the world.
“We will be able to provide very high-speed, very data-intensive signals,” said McMillan. “All [SB-S signals broadcast from flight decks] will give position reports – altitude, latitude and longitude, ground speed, a time stamp, of course, and direction of travel.” All this information will be encoded into every packet of data transmitted.
Today’s ICAO positional-signal reporting standards for aircraft operating outside airspace under active air traffic management (ATM) surveillance offer air navigation services providers (ANSPs) the ability to maintain procedural oceanic separation standards of 30nm laterally and 30nm in train.
However, McMillan said Inmarsat is working with ANSPs to provide position-reporting signals at increased frequencies, its first target being to allow 25nm/30nm procedural separation but its aim being to improve that interim goal to offer 20nm/20nm separation.
But SB-S will have the capability to broadcast positional signals continually. This could potentially let SB-S allow active ATM surveillance of aircraft in regions of oceanic airspace and remote territorial airspace, though probably not of aircraft over the North and South poles (because Inmarsat’s SwiftBroadband service isn’t available over either pole).
McMillan revealed that Inmarsat is performing evaluation work with two airlines – reported by Runway Girl Network to be Hawaiian Airlines and FedEx Express – to reduce the guaranteed latency (the lag time between a positional signal being broadcast and an ANSP receiving it) to a figure in the 3-to-5-second range.
This range is well below the 8-second latency standard ICAO requires for active ATM surveillance. If Inmarsat achieves this target with SB-S, it would represent the first step in SB-S potentially becoming an important ATM surveillance tool.
“For active air traffic management surveillance [using SB-S], a lot of things have to happen,” said McMillan. “This is a network approach. But we’re actively working with several ANSPs to explore those processes. It would need data processing and integration capabilities.”
In addition to providing timely positional reports, each SB-S signal will also be able to convey a great deal of other information.
Of prime importance for aircraft-tracking purposes, particularly during flight emergencies, is that SB-S will allow real-time flight-data streaming from aircraft experiencing emergencies – a capability Inmarsat calls a “Black Box in the Cloud”.
If, as ICAO plans to mandate for aircraft built from 2021 onwards, aircraft in distress are required to provide continuous autonomous tracking, SB-S could prove a highly valuable technology.
ICAO and other aviation organisations are now discussing how many parameters autonomous flight-data streaming signals would need to convey.
Today’s flight data recorders continuously measure thousands of flight parameters describing the manner in which an aircraft is flying and its performance and systems status as it flies, noted McMillan.
ICAO’s discussions with others are focusing on “which parameters are vital for us to have a very sophisticated and comprehensive understanding of what is happening on the aircraft”, she said. “Our understanding from NTSB [US National Transportation Safety Board] officials is that we’re talking 70 to 100 parameters to pretty clearly understand what is going on with the aircraft.”
Adds McMillan: “In my mind, it’s a game-changer as me move forward.” However, she recognises there are “a lot of political sensitivities, a lot of stakeholder interest,” in how the tremendous amount of cockpit data SB-S will be able to broadcast will be used.
“There are a lot of competitive considerations, but also a lot of legal and labour-related considerations. That [regulatory] activity will need to happen in parallel,” said McMillan.
Given SB-S’s ability to broadcast very data-intensive messages, it will be able to offer aircraft operators much more than just flight-tracking and real-time flight data streaming in emergencies.
Comparing the capabilities of SB-S with those of flight-deck satcoms two years ago to the difference between an iPhone and an old rotary phone, McMillan said SB-S will offer many new aircraft data-transmission capabilities to operators of aircraft not traditionally equipped with satcoms equipment – particularly single-aisle aircraft not flown on oceanic routes.
Particularly important is CPDLC. “For all 4-D trajectory-based operations,” including those the FAA’s NextGen and Europe’s SESAR air traffic management initiatives envisage, “you can only do CPDLC, wherever you are,” said McMillan. “VHF is already saturated.” With SB-S, “you can do more integrated ATM functions.”
Oher potentially important applications SB-S will provide to aircraft operators, whether of long-haul widebodies or short-haul single-aisle aircraft, include in-flight transmission of engine health monitoring data, electronic flight bag updates, and real-time updates of weather and flight plan information to allow re-routing and more efficient flight profiles. Applications, some not yet thought of, will exist beyond these.
Airbus has chosen Inmarsat partner Cobham to provide the satcom equipment which will give A320s and A330s SB-S service, beginning in 2018. McMillan noted other avionics companies, such as Honeywell, are developing integrated cockpit satcom systems, one developer aiming to do so for retrofit of existing aircraft as well as line-fit for new aircraft.
“All [these manufacturers] will be seeking line-fit positions with Airbus and Boeing,” she said, adding that the huge weight reductions manufacturers have achieved for satcom equipment and antennae in the past few years “opens up possibilities for other aircraft types as well”.
So space, not the sky, is the limit, it seems, in terms of possibilities for future flight-deck communications functionality.