Qantas Pioneers Future Air Navigation Systems

Although referred to in current terminology as FANS (Future Air Navigation System), its immanency has necessitated a name change. Qantas management, taking the lead, has opted for the descriptive title of “Communication, Navigation, Surveillance and Air Traffic Management,” using the acronym CNS/ATM for short. It is a compliment to Qantas that the new term is rapidly being picked up around the world as international airline management comes to realise the economic implications of the new system.

Background to the Development of CNS/ATM

The driving force behind the development of the new system is simple economics: the need to make more efficient use of the existing airways system. At present, significant delays are occurring all over the world due to air traffic density, requiring extra fuel to be carried to avoid possible diversion. As an example, Qantas carries extra fuel on flights to Europe just to cope with the “traffic jams” which are a nightly occurrence over the Indian subcontinent. Every ten minutes of holding represents two tonnes of extra fuel.

The Problems of Oceanic Air Traffic Management

It is an anachronism that despite the sophistication of modern aircraft, the air traffic system controlling transcontinental flights remains fundamentally much as it was when first set up after WWII. Oceanic and transcontinental Air Traffic Control (ATC) presently relies on routine position reports passed verbally on either VHF or HF radio. However, because of time delays, transmission problems, and language difficulties, large separation standards—in the order of 80 to 160 nm (148–296 km) along the aircraft’s track—are the present norm.

ICAO has recognised that this can only be achieved effectively through:

1. Automatic Dependent Surveillance (ADS): This allows onboard avionics to automatically report the aircraft’s position at variable intervals.
2. Controller/Pilot Datalink Communications (CPDLC): This manages air traffic flow through two-way datalink communications.

The Qantas Initiative

Following a meeting of the Informal South Pacific ATS Coordinating Group (ISPACG) in May last year, Captain David Massy-Greene proposed that a consortium of Pacific carriers (Qantas, Air New Zealand, Cathay Pacific, and United Airlines) set out their own requirements for Honeywell, the 747-400 Flight Management System (FMS) manufacturer. This resparked Boeing’s interest, resulting in them taking on the project once again.

The Proposed CNS/ATM System

The system is based on linking the FMS to the aircraft’s ACARS (Aircraft Communications Addressing and Reporting System). To ensure the integrity of ATC messages, a process of “encapsulating” the message was developed so that its delivery in uncorrupted form can be guaranteed.

Key features include:

• Data Dictionary: Enables routine requests (like height changes) to be passed as short line items.
• Satellite Voice Communications: Ensures reliability for non-routine messages.
• Twin GPS System: Adds a vitally accurate time element to ensure a common time base for the receipt of all messages via “time stamping.”
• DARPS (Dynamic Air Route Planning System): Allows aircraft to fly the optimum computer-generated track for prevailing wind conditions, known as “Flextracks.”

The Way Ahead

The new package is expected to be in operation by April 1996 and will permit a reduction in separation to 30 nm lateral and 30 nm longitudinal. This could save some $4m annually in the Pacific region alone.

Because Boeing does not have an aircraft available for trials, the US FAA has agreed to let Qantas carry out the evaluation and validation test programme. They will issue a “remote type certificate” for the 747-400 package on completion—an unprecedented move that recognises Qantas’ significant technical ability.

The South Pacific looks set to prove to the rest of the world that there are significant financial gains to be had from CNS/ATM. Airlines that fail to adopt the concept will rapidly find themselves on the outer, unable to meet the accuracy standards required to fly international routes.