TECHNOLOGY
There can be almost 1800 flights
handled within the North Atlantic on a
busy day, making it the world’s busiest
oceanic airspace
back in the hands of its customers.NATS’
CONOPs is comprehensive, with
comparable separation standards to those
frequently observed within en-route airspace
served by traditional radar and VHF
services, but using an all satellite-based
communications, navigation and, now,
surveillance service instead.
Benefits
As the TELSTAR benefit delivery manager
my role was to identify and quantify
compelling performance benefits our airline
customers would support; to build and
secure agreement for an attractive
investment / business case; and ultimately to
assure benefit delivery when TELSTAR
transitioned into service. Typically, these
benefits quantify how much safer, more fuel
efficient or more cost-effective our services
will be for our customers, or how much
easier it makes our controllers’ tasks to
deliver improved capacity day to day.
TELSTAR is the catalyst to enable all of
these benefits to be delivered and has
commenced a NAT trial implementation of
NATS’ new CONOPs to demonstrate its
delivery, ahead of its planned permanent
introduction in 2020.
Safety benefits, beyond the rare
surveillance-informed search and rescue
support for aircraft in distress, initially
followed the work NATS led in London’s
Terminal Control airspace many years ago.
These benefits see aircraft downlinked
Selected Flight Level (SFL) presented
alongside controller assigned Cleared Flight
Level (CFL) and frequent surveillance
acquired updates enabling controllers to very
quickly detect when an aircraft was about to
execute an uncleared vertical manoeuvre
(e.g. follow a flight planned step climb
without seeking ATC climb clearance). This
was supplemented by lateral Route
Adherence Monitoring to detect when flights
deviate from their track beyond existing
permitted tolerances.
Accompanying its tools development,
NATS was one of a handful of key ANSPs
who led the development of new Advanced
36 AIR TRAFFIC TECHNOLOGY INTERNATIONAL 2020
Surveillance-Enabled Procedural Separation
(ASEPS) longitudinal and lateral separation
standards recently approved by the ICAO
Separation & Airspace Safety Panel (SASP).
These standards see longitudinal separation
minima safely reduced from the current five
minutes (c. 40nm) to as little as 14nm, with
lateral minima reduced from 23nm to as low
as 15nm. These new minima, scheduled for
publication within PANS-ATM in November
2020, provide substantial additional airspace
capacity to enable flights to be assigned their
requested trajectories (level, speed and
route), whilst also enabling the removal of
the blanket mandatory speed control that
haa been a requirement of NAT operations
for decades.
NATS estimates that this change will see
the proportion of traffic assigned its
requested trajectory increase from around
60% in 2017 to c.90% when these standards
are fully deployed and available for its
customers’ use, with c.80% being assigned
flexible speed options once speed control
changes are permanently and consistently
NATS’ focus was on making its controller’s tasks easier,
to deliver essential safety, fuel eiciency and controller
workload benefits, and to deliver the transformational
benefits of the new ADS-B surveillance system