The Kingdom of Saudi Arabia’s Air Force has become the latest air arm to see its entire fleet of Boeing E-3 AWACS (Airborne Warning And Control System) aircraft undergo Boeing’s Radar System Improvement Program (RSIP) upgrade. This follows in the footsteps of the AWACS fleets operated by the United States, NATO, the United Kingdom and France. According to Keith Burns, who manages the Saudi Arabia AWACS fleet upgrade program for main contractor Boeing, the technological effort provides a leap in detection range and sensitivity capabilities for the massive rotodome-mounted AN/APY-2 radar antenna, only made possible after the installation of a “new radar computer” along with an accompanying suite of “modernized software”.
The upgrade program also greatly enhances maintainability via the installment of more robust hardware components in a radar control maintenance panel.
The completion of the upgrade work on the last of five Saudi Arabia AWACS announced on May 23rd 2017 follows that already applied to the US Air Force 32 remaining AWACS retro-fitted from January 13,1997 to April 5th 2005, to NATO’s 17 AWACS undertaken from 1997 to February 3rd 2000, to the United Kingdom’s 8 AWACS upgraded between 1997 and December 18th 2000 and to the 4 AWACS aircraft belonging to the French Air Force brought up to standard between 2002 and June 28th 2006.
The initial deal involving Saudi Arabia’s AWACS was inked on August 7th 2008 with $42 million covering the Phase I scope of engineering works as well as the purchase of the RSIP kits from manufacturer Northrop Grumman Electronic Systems.
The subsequent Phase II-A $73 million contract was followed by another $20 million award on September 16th 2010. However the overall contracts did require that actual work of only the first of Saudi Arabia 5 AWACS would place at Boeing Field in Seattle as the remaining 4 aircraft would be modified at Alsalam Aerospace Industries in Riyadh, Saudi Arabia, “with support of Boeing engineers, technicians and a test and evaluation team” according to Boeing.
Boeing delivered Saudi Arabia’s 5 AWACS aircraft between June 1986 and September1987. The aircraft are derivatives of Boeing’s legendary 707-320B mounting atop their fuselage the powerful 1970’s era Westinghouse AN/APY-1 radar and its more modern successor the Northrop Grumman AN/APY-2 (Northrop Grumman succeeded Westinghouse Electronics Systems). These large radar ‘complexes’ have given the AWACS also known as “E-3 Sentry” advanced surveillance capabilities at ranges in excess of 200 miles (320 kilometers) for low flying targets and out to 250 miles (400 kilometers) for higher altitude targets.
The Royal Saudi Air Force has acquired the 5 Boeing E-3 Sentry AWACS thanks to the 1981 Peace Sentinel Foreign Military Sales program (which also made provision for up to 8 KE-3 refueling tankers; identifiable as KC-135 Tanker ‘clone’). Deliveries took place from 1986 to 1987. Like those operated by United Kingdom and France, Saudi Arabia’s AWACS models are powered by 4 fuel efficient CFM-56-2 high bypass ratio turbofan instead of the 4 Pratt & Whitney TF33 turbojets powering the US Air Force and NATO AWACS fleets.
With the highly publicized employment of the Saudi Arabia fighter aircraft fleet in full scale offensive operations in neighboring Yemen’s civil war, the RSIP capabilities follow previous upgrades done on the AWACS. In 1997 the Block 35.3 software upgrade was completed by increasing the memory on the IBM CC-2Er main mission computer system, itself designated Block 0. By 2003, capabilities were expanded further by the improvement of tactical data communication systems with the installation of Link 16 secure jam resistant terminals.
The AN/APY-1/-2 and AWACS Operation
With its normal crew complement of 18 an E-3 Sentry AWACS requires a four-members flight-deck crew, three technicians and 11 people assigned to core AWACS mission. For instance in the UK Royal Air Force, the mission crew itself comprises a tactical director (mission crew commander), a fighter allocator, three weapons controllers, a surveillance controller, two surveillance operators, a data-link manager, a communications operator and an electronic-support-measures operator. On NATO missions, crews consist of 12 members; a tactical director, a fighter allocator, two weapons controllers, a surveillance controller, three surveillance operators, a passive controller, a communications technician, a radar technician, a system technician depending on the mission.
The AN/APY-2 radar at the heart of the AWACS operation provides multi-mode operational flexibility split between air, maritime and electronic emitters surveillance (Electronic Support Measures). Contrasting key AWACS sub systems capabilities and their interfacing we have described on a previous post the six main Radar tactical modes as Pulse Doppler Non Elevation Scan (PDNES) mode, Pulse Doppler Elevation Scan (PDES) mode, Beyond-The-Horizon (BTH) mode, Maritime mode, Interleaved mode and Passive mode.
With full production status reached in 1997, the RSIP upgrade was, according to Northrop Grumman the most significant effort to improve the performance of the AN/APY-1/-2 radar delivering greater radar range resolution (augmented six-fold) with azimuth and elevation accuracy doubling. Overall capabilities were enhanced in keeping with modern aerial threats requirements such as small cruise missiles and reduced Radar Cross Section (stealth) aircraft. The implementation of new signal processing facilities (advanced Pulse Doppler waveforms, pulse compression) supported by the main computer hardware upgrades and installation of modern Graphical User Interface-based operator display promised overall mission efficiency increase by a factor of 1.5.
In the current context Saudi Arabia AWACS upgrade can only fully be justified within the realms of the bitter rivalry with Islamic Republic of Iran whose air force TO&E has retained lasting features (and equipment) from its 1970’s intimate collaboration with the United States. Furthermore, the IRIAF is now very likely to be sooner than later dramatically reinforced when acquisition of the powerful long range multirole Sukhoi Su-30 fighters aircraft will be enacted.
For more details on the RSIP application and AWACS evolving capabilities see our previous analysis: