freqhopping
Member
- Joined
- Jan 5, 2004
- Messages
- 7,096
Unless they (what agency?) are somehow flying under special rules / on a NSM, pretty sure they are squawking something. Perhaps they are not Mode S equipped, not on an IFR flight plan, etc. I would have to know more about the flight profile. Extremely doubtful that they just turned their transponder off because that would FU ATC routing (transponders also report altitude.) Maybe they've been assigned an altitude block, need more info. Even the Fed's LE aircraft are assigned transponder codes. Cannot speak to them being ADS-B equipped yet however.
Feds like FBI are still active in the DC area but they stopped using mode-s and went to mode C because of all the website articles about tracking their surveillance flights. Occasionally I'll hear a LIMO flight with ATC.