Choosing the Right Datalink: A
Critical Business Decision
Kim O'Neil
Advanced
Aviation Technology Ltd.
Compton, England.
Abstract
Airlines are being steadily pushed towards
air/ground data communications services that are expensive, restrictive,
limited in functionality and monopolistic. Reliance on "traditional suppliers"
(of both avionics and communications services) may lead to a costly dead end.
Airlines need to fundamentally re-appraise the data-link options that are
available and apply proper business decision processes to the issue. Airline
executives and CEOs need to ensure that the potential commercial opportunities
are fully developed.
1. Introduction
Despite aviation's hi-tech image, in some areas
we lag far behind other sectors. Few can fail to be aware of the enormous
advances in Telecommunications and Internet services. We know that the pace of
change is set to accelerate even further. Yet, relatively few of the potential
benefits are trickling through to airlines. Aircraft Communication costs are
high and functionality low. Current services are based on technology that was
developed in the 1970's - and the suppliers of equipment and services enjoy an
effective monopoly.
This does not make good reading. It should make
most Airline Executives very unhappy.
2. Communications and Data-link Services
Operational applications of data-link
communication services are easy to identify. It makes sense to know where your
aircraft are, if they are delayed and what operational or technical problems
must be dealt with. The knock on effects can lead to aircraft being diverted
(e.g. due to crew flight time limitations), passengers missing connections and
many secondary problems. Thus, it is an operational advantage for an airline to
be in continuous communication with its fleet, to discover problems as they
occur - and be able to respond, if required. Time is always money and it always
pays to know NOW.
3. Regulatory Issues
Civil aviation operates to International
standards, which take many years to develop. Aircraft equipment has to be
certified and its installation and operation approved. Radios have to co-exist
with existing transmitters and receivers (some of which are flight critical).
There are between 30 and 40 aerials on the surface of an aircraft - even
finding places to install new aerials is not simple! It is easy to understand
the reluctance of Airline Engineering Departments and manufacturers to go for
any "non-Standard" solution. Airlines who lease aircraft face particular
problems, as it is generally difficult to modify aircraft unless supported by a
Service Bulletin from the aircraft manufacturer (but that's another story!).
Aircraft manufacturers are not keen to install
any technology unless they see substantial market demand. "Substantial" in this
case means demand from airlines exceeding 20% of the available aircraft sales.
Yet aircraft manufacturer support for is usually essential. Indeed, one issue
is the way in which aircraft manufacturers attempt to direct the market in line
with their own development plans. CAAs are also reluctant to move without
industry-wide consensus.
In short, aviation processes tend to lead to
"safe" but obsolete solutions. This is why Telecom operators have avoided
Aviation Communications. Ironically, they see aviation as heavily regulated,
the cost of entry high and the market comparatively small. It's hardly
surprising there is little to attract new players to this market.
4. Data-link Fundamentals
Data-link is a subject that rarely attracts
Airline Managers. Yet, the choice of data-link will affect many business areas
i.e. it is not just a technical matter.
4.1 Satellite Communications
Satellite communications are very expensive, but
prices are coming down. The key advantage is global availability. The current
de facto supplier is Inmarsat with its high orbit geo-stationary satellites.
There is no obvious reason why other satellite systems cannot also be employed.
Low Earth Orbit (LEO) systems offer many advantages including lower cost,
higher availability and greater redundancy. There are some interesting
opportunities to consider. The major issue is the availability of aircraft
equipment and the co-operation of CAAs in certification.
4.2 Terrestrial Communication Services
The aeronautical spectrum is generally
controlled by the Civil Aviation Administrations. Thus, operating any data-link
service requires the co-operation and agreement of the CAAs. Who, in turn, have
their own services to provide…… The CAAs are very jealous of their
position and will not easily give way to any competitive pressure that may
adversely affect the services they offer.
Thus the issue of terrestrial communication and
data services is highly charged.
Surprisingly, the position of the CAAs is very
complementary to the two major data-communications service providers. Over the
years, the relationship between these parties has developed to the point where
they share common interests and see a common threat - external competition.
Both want to maintain their monopoly of services and their market niche.
5. Which Data-link?
Currently, the main contenders are:
- ACARS (the current single channel 300 bits
per second air/ground link)
- VHF Datalink 2 (single channel air/ground
link)
- VHF Datalink Mode 3 (3 channel voice, one
data channel)
- VHF Datalink mode 4. (two way, multi-user
air/air, air/ground link)
VDL mode 2 and 3 share a common
modulation scheme (not used by any other mobile communications service), which
is sensitive to interference. They are also difficult to operate within the
required 25kHz channel spacing. VDL mode 2 only supports a single air/ground
channel and has a very limited operating life before becoming hopelessly
obsolete. The radio horizon of an aircraft in flight is very large, so ground
stations must be co-ordinated to reduce the risk of interference. This
drastically reduces its capacity.
VDL mode 3 is the preferred option of the
FAA and is their "big idea" in digital communications. But it suffers the same
intrinsic flaws suffered by VDLmode2. The development period for this
technology coupled with the need to provide a transition strategy (whereby
normal analogue VHF services are maintained, as digital services are
introduced) means that the introduction of this technology will be delayed many
years.
VDL mode 4 allows many aircraft to
communicate simultaneously on the same frequency. It also allows competing
communication providers to share the same frequency. It is a cellular
technology and does not experience the interference problems common to the
other technologies. It has greater capacity and a much wider range of
application (including future Air Traffic applications) and is the basis for
the latest telecommunications solutions.
However, the very characteristics that benefit
VDL mode 4 also threaten existing service providers. Hardly surprising they are
less than enthusiastic.
6. Competition Issues in the Communication
Market
Two players have made investments over the last
few decades and divided the market into two global monopolies, with relatively
little real competition between them. The type and pricing of their services
does not threaten the other monopoly providers of communications services - the
CAAs.
It is surprising that airlines, who face
competitive challenges in every part of their business, should accept the
existence of global monopolies. It is difficult to gain leverage over such
suppliers - if Airlines do not insist on solutions that enable competition.
The development of the Internet and secure
virtual private networks that span the globe, are clear indicators that not
only can the costs of Communications services be brought down, but services and
products can be expanded to provide commercial opportunities to airlines e.g.
passenger data and communications services including Internet and broadband
access.
Airlines should insist on the de-regulation of
the telecommunications market in aviation in ALL its forms. Without competitive
pressure, prices will always be higher, services poorer and commercial
opportunities limited. Airlines need to urgently challenge the restrictive
approaches of aircraft manufacturers and CAAs. |
