The most important attraction of MAKS 2011 was the first public presentation of Russia's new-generation PAK FA fighter, also known as the Sukhoi T-50.
Previously the T-50 had only been displayed during closed presentations for the Russian Prime Minister and military delegations from India. At this year's show, Russian and Indian military officials did not want to display the PAK FA at close quarters, so it was absent from the static park and only took part in the flying display.

PAK FA Debut

When MAKS 2011 opened on August 16, the two T-SO prototypes had made 84 flights, 36 of which took place in 2010. On March 9,2011 a T-50 exceeded the speed of sound for the first time.
Both of the flying prototypes, T-50-1 and T-50-2, were displayed at Zhukovsky. The daily display began with a flypast of both prototypes followed by an individual flight demonstration during which the aircraft did not exceed 5g
or use thrust vectoring control. Formation flypasts were also made with the Su-34 and Su-35.
On the last day of the show, T-50-2 suffered from an engine flameout during take-off. The pilot aborted the take-off and deployed the brake chute with no resulting damage to the aircraft. It was a spectacular failure, but one without serious consequences; nor was it the first incident - at least two had already occurred before the show - and indicates that the air intake and engine control still need refinement. The control system used on the T-50's AL-41F1 (Izdeliye 117) engine is the one component that distinguishes it from the simpler AL-41 F1S (Izdeliye 117S) engine used by the Su- 35 fighter.
Prototype T-50-1 (No 051) made its maiden flight on January 29, 2010. To date the flight trials have been paused twice: from October 2010 to February 2011, and from June 14 to August 4, when the aircraft was presented to the commander of the Indian Air Force and underwent overhaul and modification.
In its aft section, between the engines, an anti-spin parachute has been mounted, indicating that the aircraft will soon begin test flying in the extremes of the flight envelope. Strengthening ribs have also appeared on the tail- planes (also found on 1-50-2) and strengthening pads are also located on the tail-boom of T-50-1.
The second prototype, T-5Q- 2 (No 052), flew for the first time at Komsomolsk-on-Amur on March 3, 2011. After a few flights there, it Was loaded aboard an An-124 and flown to Zhukovsky on April 3.
For reasons unknown to the author, the aircraft began to fly at Zhukovsky on August 10 after a four-month break. The paint scheme of both aircraft is the same.
The third aircraft (T-50-3) is due to fly this autumn.
In comparison with its predecessors, T-50-3 will be fitted with a N036 X-band forward radar and a full array of integral electro-optical sensors as part of the 101KS system. The Head of UAC and Sukhoi, Mikhail Pogosyan, said during MAKS that the maiden flight of the fourth prototype T-50 would also be made this year.
The PAK FA has an almost guaranteed successful future.
Its technical layout has already been specified and there are no problems with funding of the research and development work. After signing the contract with India for development of the Russian-lndian version, called the FGFA (fifth-generation fighter aircraft), the first order for 200 aircraft in addition to the Russian Air Force's order is almost certain.
In Russia the first batch of up to ten aircraft will be built for military trials due to take place between 2013 and 2015. Subsequently, the Russian National Armament Programme assumes the purchase of 60 production PAK FA fighters during 2016-2020.
During MAKS 2011, the Commander-in-Chief of the Russian Air Force, Alexander Zelin, said the air force is satisfied with results and the pace of works on the PAK FA. "For the time being we are on schedule. There are no problems that would require us to stop and rethink [the programme]," he said, adding that the first test aircraft would be handed over to the military in 2013 (referring to trials at the Russian Ministry of Defence test facility at Akhtubinsk) and production aircraft in 2014- 2015 (referring to an initial batch of aircraft for operational evaluation at Lipetsk).

Atoll Electro-Optical System

During MAKS 2011 no new information materialised about the PAK FA aircraft itself, but detail about components of the aircraft's equipment was available. After years of work in secrecy, Sukhoi's sub-contractors were keen to demonstrate their achievements.
The presentation of the 101KS Atoll OEIS (optiko-elektronnaya integrirovannaya sistema - integrated electro- optical system), made for the PAK FA by UOMZ at Yekaterinburg, was the biggest surprise at this year's show. Head of UOMZ Sergei Maksin said that OEIS links all electro- optical sensors on the fighter and "completely controls the situation around the aircraft in all optical bands". According to the company, six electro-optical sensors will be mounted on the surface of each production standard T-50. According to another announcement, the complete 101KS suite will be integrated on the third prototype, T-50-3.
For now, the second prototype, T-50-2, is fitted with two of the sensors: the first is the 101KS-V air-to-air sight (V for vozdukh, or air) mounted in a turret on the starboard side in front of the cockpit. It can detect, identify and track multiple airborne targets simultaneously. The second is the 101KS-O (O for oborona, or defence) fitted in a turret placed on the upper fuselage spine aft of the cockpit.
This sensor is a laser-based directional countermeasure for heat-seeking anti-aircraft missiles.
Two of the Atoll system's other sensors are each designated 101KS-U and are described by UOMZ as a subsystem providing the crew "with information about the air and ground situation". These ultraviolet sensors will probably be located on both sides of the forward fuselage section.
The other two 101KS Atoll system sensors were not displayed at MAKS, and their designation remains unknown. Drawings published by UOMZ show their 'rooftop' shape containing six windows under which UV and laser sensors are mounted. It is likely that one such sensor will be located under the T-50's nose and the second on the upper surface of
the 'sting' protruding between the engines. In addition, the Atoll system has a ground target detection, identification and tracking system designated the 101KS-N (N for nazemnyi, or ground), carried in a pod suspended under the aircraft's engine air intake.

Radar

Elsewhere at MAKS, the Tikhomirov NIIP Institute, based at Zhukovsky, displayed the N036-01-1 active electronic scanning antenna of the forward X-band N036 radar for the PAK FA. An MPP-8 block with its 75 transmit- receive (T/R) modules was also displayed together with N036UVS (universalnaya vychislitelnaya sistema - universal computing system) boxes. The forward radar has an oval antenna 900mm (35in) wide and 700mm (27in) high with 1,522 T/R modules sloped
15‘ up to the aircraft's axis. The complete N036 radio-location systems comprise five radars - the front X-band (centimetre) radar, two small N036B X-band side radars and two L-band (decametre) N036L radars mounted in the wing leading edges, and used only for target identification and IFF.
The N036 radar is a main part of the Sh121 MIRES (Mnogofunktsyonalnaya Integrirowannaya Radio-Elektronnaya Sistema - multifunction integrated radio-electronic system); its second component, developed by KNIRTI at Kaluga, is the L402 integrated ECM system, but this was not displayed at MAKS.
NIIP's Head, Yuri Belyi, said the three front radars are already assembled, including two for stand tests and one to be fitted in T-50-3 later this year. Two more radars are being assembled at NIIP and the GRPZ facility at Ryazan is preparing for series production. Work on the N036 radar is divided into stages. According to Belyi, stage-one work is concentrated on the forward X-band radar and its integration with the ECM and other systems. During the second stage the L-band, followed by the N036B side X-band radars, will be produced. It's possible that Indian companies will be tasked with making the X-band side radars under the common FGFA programme while a pod- mounted Ka-band (millimetre) radar is included in future plans.

Systems

Polyot, based in Nizhny Novgorod, presented the S111-N coded communication system for data exchange with other aircraft plus ground and airborne command posts. According to official information, the S111-N has ''much better functional, operational and economical properties than the TKS-2M system" used on the Su-27.
Meanwhile, NPP Zvezda, of Tomilino, near Moscow, showed the new K36D-5 ejection seat intended for the T-50; and the SOZhE-50 pilot life support system, comprising anti-g harness, PPK-7 pilot suit and ZSh-10 helmet. By comparison with the current K36D-3.5, the K36D-5 seat has a better minimum speed and height ejection envelope and serves an bigger range of pilots' weights.
The only new type of internal weapon for the PAK FA debuting at MAKS 2011 was the 250kg (550lb) KAB-250 precision-guided missile. The weapon has a satellite navigation receiver but its guiding sensor (probably a laser gyroscope-stabilised type) was covered-up for the whole exhibition. Measuring 3.2m (10ft 6in) in length, the KAB-250 has a 255mm (10in) diameter, a 550mm (21 in) fin span and is mounted in the PAK FA's weapons bay on a UVKU-50L ejection launcher.

МОСКВА, 11 ноября. (АРМС-ТАСС). До конца года должны начаться летные испытания третьего опытного самолета ПАК ФА, который будет оснащен бортовой радиолокационной станцией (БРЛС) с активной фазированной антенной решеткой (АФАР). Об этом сообщается в сегодняшнем номере газеты "Жуковские вести".
БРЛС с АФАР в состав высокоавтоматизированной многофункциональной интегрированной радиоэлектронной системы (ВМИРС) истребителя 5-го поколения создана в НИИ приборостроения им.Тихомирова. Опытные образцы этого оборудования можно было увидеть в экспозиции НИИП на авиасалонах МАКС-2009 и МАКС-2011.
На данный момент созданы три опытных образца бортового радара с АФАР для ПАК ФА. Отработка первого из них на стенде НИИП проводится уже в течение более двух лет, второго - около года. Третий опытный образец перспективной РЛС в текущем году прошел стендовые испытания и после приемо-сдаточных испытаний был установлен на третий опытный самолет 5-го поколения, сообщает издание.
По имеющейся информации, на авиазаводе в Комсомольске-на-Амуре завершается подготовка к летным испытаниям третьего ПАК ФА. Планируется, что после нескольких тестовых полетов начнется отработка радиолокационной аппаратуры в составе бортового комплекса авионики.
Разработчики НИИП не скрывают трудностей, которые им приходится преодолевать, создавая РЛС с АФАР с использованием отечественной электронной компонентной базы. Освоение ее производства осуществляется с большим напряжением. В особенности это касается производства приемо- передающих модулей.
В состав ВМИРС истребителя 5-го поколения входят пять радиолокационных постов. Приоритет в разработке и испытаниях отдается передней АФАР и ее интеграции с другими бортовыми системами. БРЛС с АФАР имеет много новых режимов работы, которые впервые будут применяться в отечественной практике.