Can the Indian S-400 missile shoot down a Chinese J-20 fighter?

S-400 Triumf is a high altitude air defence interceptor missile, which is capable of bringing down the most advanced fighters like Sukhoi, F-18 Super Hornet, F-15 Eagle; the deadliest bombers like B-1B Lancer, B-52 Stratofortress; and the AWACS planes like Boeing E-3 Sentry. Its powerful radar can scan an area of upto 800 km using its electronic beam steering and track over 100 targets simultaneously. When it locks on to an aircraft, the plane has zero chance of escaping.

Chengdu J-20 fighter is China’s latest war bird that is designed to evade enemy radars and fighter aircraft by remaining “invisible” in the air. It is the world’s 3rd operational stealth fighter, after F-22 and F-35 of the US.

Now the question: Can an S-400 detect, track and shoot down the J-20 fighter? And why?

There is a catch about making stealthy planes. These jets can evade conventional radars quite well BUT there are other ways of detecting stealth jets. One such method is called Passive Tracking.

Passive Tracking is a technique in which the radar detects the Radio Frequencies emanating from the fighter jets. Remember, each fighter jet is communicating regularly with its AWACS controllers or its partner jets to remain on course. Kolchuga passive sensor – Wikipedia

So, if the J-20 is coming near the Indian airspace, the S-400 radars can use their “passive sensors” to pick up radio communication between the jets. Now the S-400 radar is so advanced that it can pinpoint the location of the J-20 with this method and then allow its operators to fire a missile at that target. {At a speed of 25,000 kmph, that is.}

When press corps asked former IAF Chief Dhanoa about the J-20 Fighters, his reply was this: “Our radars near the border have been able to pick up J-20 from several kilometers away”. Indian Air Force Claims China’s J-20 Stealth Fighter Jets Are Not Undetectable

Now, you can guess why Indian radars were able to detect J-20s. Perhaps some of those radars already have the “passive sensors” inbuilt into them.

Logically, if an S-400 can detect and track the J-20, it can CERTAINLY shoot it down!!

Edit: Some readers are equating J-20 stealth with F-35 JSF and assuming that F-35 can also be shot down with S-400. That’s an incorrect assumption because, F-35 jets use Multi-function Advanced Data Link (MFAD) to communicate with other stealth jets and AWACS planes. MFAD cannot be tracked by passive sensors. Multifunction Advanced Data Link

Source:- Quora