# How do stealth aircraft get ATC?

I believe that all aircraft must be controlled under ATC's instructions to fly safely especially when take-off and landing. And, most ATC instructions are conducted by ground radar which controllers use.

But I know that the stealth aircraft (including B-2, F-22 etc.) aren't captured on radar display owing to their stealth ability. If so, how does a controller give instructions like radar vectors to stealth aircraft?

I know that there's are primary and secondary target when using radar, and the controller must use primary target to vector aircraft. I guess stealth aircraft can be captured by secondary radar but not primary target.

• They switch on their transponder. Simple as that. – Peter Kämpf Feb 17 '16 at 7:30
• the controller must use primary target to vector aircraft This is wrong. RADAR vectors are given using secondary RADAR. – Simon Feb 17 '16 at 9:10
• No, controller must use the secondary target to vector aircraft. There was even talk about turning the primary radar off altogether. Stealth aircraft can simply turn on the transponder to make themselves visible on the secondary radar when flying in friendly territory and secrecy is not required. – Jan Hudec Feb 17 '16 at 9:16
• It doesnt really matter if it's primary or secondary radar target. It must be identified, then you can give vectors and assign altitudes. You can give radar vectors to primary target, they just need to be identified... – SentryRaven Feb 17 '16 at 10:53
• It's also not true that stealth aircraft are completely invisible to radar. – DJClayworth Feb 17 '16 at 18:12

The concept of ATC is based on primary radar targets, secondary radar targets and radio communication being used to determine the position of aircraft and establish separation.

The concept of stealth aircraft is to reduce production of primary radar targets and being able to turn off transponders to disable secondary radar targets being visible. Stealth aircraft also do not communicate on frequencies during tactical missions, they are designed and meant to reduce radio emission to enable the stealth features.

If they are not on a tactical mission and stealth is not required, they will simply turn on their transponders and communicate with ATC on the required frequencies.

• How are you defining "on a tactical mission"? – fooot Feb 17 '16 at 15:47
• A mission that requires stealth. ;) @fooot – SentryRaven Feb 17 '16 at 15:58
• What if they are in controlled airspace though? – fooot Feb 17 '16 at 16:04
• If you are on a stealth sortie, you do not care about controlled airspace. You are either in hostile airspace or within a MOA/TRA practicing... – SentryRaven Feb 17 '16 at 16:07
• Wouldn't it be strange to the hostiles that a mysterious aircraft just conveniently disappears before entering their airspace? – fooot Feb 17 '16 at 16:47

First off:
"I believe that all aircraft must be controlled under ATC's instructions to fly safely especially when take-off and landing."

Not true. When I fly my small Cessna from an untowered airport in VFR conditions, I don't file a flight plan, and I don't talk to ATC. I do make annoucments on the CTAF, but that is not even required. I would be completely legal to take off, fly and land, never turning on my radio or talking to anyone. "See-and-avoid is the rule.

Secondly:
Stealth aircraft are stealthy only when they are trying to be. Something as simple as lowering the landing gear would provide a strong radar return. The transponder can indicate position, ADS-B can provide precise updates, and the pilot can verbally describe their position to ATC.

ATC concept is based on cooperative targets (i.e. willing to send their position to the ATC radar). I suppose that they are equipped on board with a transponder that is switched on when there is a need for air control.

They attach radar reflectors so as to be visible to ATC's primary radar. This is in addition to turning on the transponder (secondary radar).