Originally Posted by
treadigraph
These are yer actual USN P-3Cs - one up now out of Jacksonville, 161121.
Not sure that is correct at all 161121 was retired to AMARG [Davis Monthan AFB, AZ] 02/2021.
A lot of P-8s [and before that P-3s] used "tactical" mode S codes. Unfortunately a lot of the tracking sites have not realised this and attached a serial to a mode S code. Hence that is why you probably saw 161121 listed.