Radar
The F-22 Raptor is equipped with a low observable, APG-77 Active radar.The APG-77 is having a detection range of about 240 km versus a 1 m² target. The PAK-FA will be equipped with an improved AESA derivative of the Irbis-E radar of the Su-35, the PAK-FA AESA outranges the APG-77 of the F-22 Raptor, as it has a detection range of about 400 km against a 3 m² target
Both aircraft, the F-22 Raptor and the PAK-FA will dominate the skies for at least the next decade. With the introduction of the PAK-FA and Chinese 5th Generation Fighters like the J-20, the F-22 isn’t the only “superfighter“ anymore.
Beyond Visual Range combat
Beyond Visual Range combat is usually won by the aircraft which detects its enemies before being detected. If radar is used:Raptor detects PAK FA with 0.01m², using the APG-77 at ~40 nautical miles but PAK FA detects Raptor with 0.0001m² at ~15 nautical miles.
If IRST is used:
If the PAK-FA would use its IR-sensor (50 km maximum range), it would detect the IR-shielded F-22 at a maximum distance of 20 nautical miles.The F-22 is not equipped with an IRST.