and the Identification Friend or Foe/Tactical
Digital Information Link (IFF/TADIL) systems.
It turns at a rate of 6 RPM, enabling the
S-band pulse Doppler surveillance radar to
survey, every ten seconds, an area larger
than 200,000sq miles (519,998km²) and
extending over 250 miles around the aircraft.
Although later Saudi, French and British
E-3s feature more powerful 24,000lb st
(106.76kN) CFM International CFM56-2A-2/3
high-bypass turbofans, USAF and NATO
Sentries were delivered with four 21,000lb
st (93.41kN) Pratt & Whitney TF-33-PW-
100/100A turbofan engines.UPGRADES
Since entering service, the E-3 has had
numerous upgrades to its mission systems
and cockpit avionics suite.
Begun in 1984, Block 20/25 modifications
updated the Core and Standard E-3As with
a faster, more capable IBM CC-2 computer.
The incorporation
of five additional
situation display
consoles increased
the number to
14, improving the
system’s ability
to process and
disseminate
information.
ECM-resistant
voice communications
modifications
meanwhile boosted
the number of radios
to 20 through the
installation of a third
HF and five UHF
units, while the Core
model’s AN/APY-
1 radar gained a
maritime surveillance capability.
Once upgraded, the Core and Standard
aircraft took on E-3B and E-3C designations
respectively, with the first E-3B accepted on
July 18, 1984. The programme, completed
in summer 1990, was followed by installation
of jam-resistant Have Quick radios, which
finished in 1994.
Development of the Block 30/35 upgrade
began in May 1987, with modifications
to the first aircraft completed in October- It added the passive AN/AYR-
1 Electronic Support Measures (ESM)
system, a NAVSTAR GPS navigation
capability, upgraded TADIL-J secure data link
communications and an upgraded central
mission computer.
Developed from the US Army’s Advanced
Quick Look (AQL), the ESM’s passive
sensor detects and acquires radio frequency
emissions from threat radars at distances up
to 300nm (556km). It identifies the emitter
and determines the type of platform, and
information from the ESM is correlated and
displayed with inputs from other sensors on
the operator consoles for analysis.
The system can classify more than 100
targets in ten seconds and scan across its
entire frequency band in two seconds. Itsantennas are installed under the aircraft nose,
tail and in cheek locations on the forward
fuselage aft of the cockpit.
The 552nd Air Control Wing (ACW)
declared IOC with the upgraded variant in
May 1998 and modifications were completed
on October 20, 2001 when Sentry serial 75-
0557 was delivered by the Oklahoma City Air
Logistics Center (OC-ALC) at Tinker.
Started in 1994, the Radar System
Improvement Plan (RSIP) replaced theradar computer and upgraded the operator
consoles, system hardware and software.
It also increased the radar sensitivity to
detect and track smaller targets, such as
cruise missiles, at greater distances and
improved the system’s electronic counter-
countermeasures (ECCM) capability,
reliability and maintainability.
Initial operational test and evaluation
(IOT&E) ran from August 1995 to October
1996, enabling Low-Rate Initial Production
(LRIP) to begin. RSIP-equipped E-3B/Cs
achieved IOC in June 2001 and the 32nd and
final upgraded Sentry was accepted by the
USAF on April 15, 2005.
The next-generation identification friend or
foe project provided new secure Mode 5 and
Mode S civilian air traffic control capabilities
for 31 aircraft, beginning in 2015. Current
modernisation is focused on upgrading
the battle management mission, combat
identification systems and cockpit avionics.
Sharing many
elements with the
NATO Mid-Term
upgrade plan for
the type, the $2.7
bn Block 40/45
programme began
in 2003. The largest
upgrade in the
AWACS’ history,
E-3G standard, it
replaced the mission
computing system
with open-architecture,
commercial off-the-
shelf hardware and
software, new mission
consoles and battle
management tools,
and reduced weight
by 4,000lb (1,814kg).
The new software enhances tracking
and combat identification capabilities,
providing operators with a better picture of the
battlespace, and the open-architecture will
make future upgrades quicker.
ESM updates under Block 40/45
expanded target identification and processing
capabilities and enable greater integration of
information from sensors both on- and off-
board the aircraft.
Flight trials began using E-3 test
system aircraft TS-3, 73-1674, on July 15,- Mission systems air tests followed
between April 2007 and July 2008, when the
development and demonstration phase ended.
64 Aviation News incorporating Jets April 2018Above left: An E-3G from the 552nd Airborne
Warning and Control Wing on the ramp at
its base in Oklahoma. Greg L Davis/Public
Domain Image
Above right: Tinker AFB in Oklahoma is still
the primary home for the USAF’s Sentry fleet,
including E-3G 82-0006. Greg L Davis/Public
Domain ImageInside the cockpit of 77-0351, the first of
24 E-3 Sentries to undergo the glass flight
deck modification known as DRAGON.
USAF/Kelly White62-67_e3sDC.mfDC.mfDC.indd 64 02/03/2018 17:53