into terrorist weapons suddenly became real
and E-3D controllers took on the new role
of co-ordinating fighters to intercept and
possibly shoot down threatening airliners.
Since then an E-3D has been held on
round-the-clock alert at Waddington, ready
to launch as a national airborne command
post in case of a major terrorist incident.
The aircraft took on further duties after a
surge in incursions into the UK air control
zone over the North Atlantic and North Sea
by Russian long-range bombers following the
2014 annexation of Crimea. During incidents
involving multiple such aircraft, the alert E-3D
launches to extend the range of UK radar
coverage far out into the North Atlantic and
help manage RAF and NATO fighters.
Owing to their central role in UK air operations
at home and abroad, the RAF placed a priority
on upgrading its E-3Ds to keep them as closely
aligned as possible to the configuration of
those of their US, French and NATO allies.
This programme of continuous investment in
the type came to an abrupt end with the 2010
Strategic Defence and Security Review (SDSR),
which postponed a major upgrade of the RAF’s
Sentries. It was the start of a slippery slope.
To try and address the growing problem of
obsolescence, the 2015 SDSR committed
to keeping the E-3D fleet – now reduced
to six from the original seven as a cost-
cutting measure – in service until 2035
through a yet to be contracted upgrade
project known as the UK AWACS Capability
Sustainment Programme (CSP).
The fleet at Waddington is now suffering from
poor availability and becoming increasingly
expensive to keep in the air, according to
RAF officers. Freedom of Information (FOI)
documents reveal they flew 3,560 hours in
2005-6 but only 1,270 hours in 2016-17.
Only three are classed as being in the
RAF’s forward fleet and ready for operations,
according to other FOI documents from
February. Meanwhile they were all grounded
for several months from November 2016
because of a fire risk scare that required
an expensive modification programme.A new AWACS?
In the first months of this year a senior
RAF officer told AFM that the viability of
the UK AWACS CSP was now in doubt
because of the cost of bringing avionics up
to standards that meet UK and international
civilian aviation authority requirements.
The source explained: “The E-3D’s
mission system and operational avionics
are ‘historic’, so it does not look like
a good investment spending more
money just keeping them going.”
Radar technology has undergone a
transformation in the 40 years since the first
E-3 entered USAF service. The distinctiveWestinghouse (now Northrop Grumman) rotating
AN/APY-1/2 radar mounted above the E-3’s
rear fuselage was revolutionary when it was
designed but is now seen as near obsolescent.
Mechanically rotating radars have been
overtaken by active electronically scanned array,
or AESA, radars. These are fixed-mounted,
with antennas controlled by computers, and
use advanced software to analyse any returns.
AESA technology brings major advantages.
Firstly, radars are smaller and lighter since they
don’t require mechanical mountings to rotate
them. They can be installed in much smaller
aircraft, such as large business jets, drastically
reducing acquisition and operating costs.
In turn, rapid advances in computer
technology mean radar returns can be rapidly
analysed, and the resulting information
distributed over communication networks
in a matter of seconds. This significantly
reduces the number of controllers needed to
operate an AWACS-type aircraft. And AESA
radars can be rapidly switched between
roles – including airborne, ground and
maritime surveillance – making it possible to
operate multi-role surveillance aircraft that
require just one or two small antennas.
The critical difference between old, mechanical
radars and new AESA systems is the speed at
which they can be updated via new software
‘drops’, without requiring expensive and time-
consuming changes to hardware and airframes.E-3D Sentry AEW1 ZH101 from No 8 Squadron at Thumrait air base in southern Oman during Exercise Saif Sareea III, as part of 140 Expeditionary Air Wing. The
fl eet has been reduced from seven to six as a cost-cutting measure. Crown Copyright
Below: An RAF Voyager arrives at RAFO Musannah, Oman, transporting troops and freight into the
country for the recent Exercise Saif Sareea III. Airbus has suggested that some of the service’s 14
Voyager airframes could be adapted for the AEW&C role in future. Crown CopyrightRAF 100
70 // DECEMBER 2018 #369 http://www.airforcesmonthly.com