In recent weeks the radio hobby has been a buzz about the new "Convoy" callsign being used by various navy air transport aircraft. Sometime around the second week in November, monitors and Mode-S boxes started reporting the Convoy (CNV ####) callsign and the tie ups were associated with various US Navy C-9B, C-20, C-40, C-130 aircraft and USMC KC-130 tankers.
After a detailed study, the MMP team has broken the number system being used by these aircraft. The first number indicates the aircraft type and the next three numbers are the last three numbers of the aircraft's assigned mission number from NALO. Here is how it looks in brief.
Convoy 2### C-20 aircraft
Convoy 3### C-130 aircraft
Convoy 4### C-40 aircraft
Convoy 9### C-9 aircraft
We still need more intercepts to lock down the Navy C-12 aircraft convoy number series, since we only have one noted to date with no total tie-up. We have also seen a few oddballs as well as noted below:
CNV 61R1 C-130T/BD-161 VR-64 NAS Willow Grove. PA 165161 [Note the first two callsign numbers and the last two numbers of the Buno number]
CNV 467B C-40A/RY-833 VR-59 NAS/JRB Fort Worth, TX AE0976 165833
CNV 0921B KC-130T/NY-597 VMGR-452 Fort Stewart IAP, NY AE03D4 #164597
CNV 900 C-12
So the first number indicates aircraft type and the last three are the last three from the NALO assigned mission number.
I should also mention that I have also seen these aircraft use the NALO callsign, but sporadically. My first record of one was back in Dec 2007 and the last time I saw one was on 12/2/2008.
There may be a bit more to this story, but that will have to wait for now. More as we get additional intercepts in our monthly Milcom column in Monitoring Times magazine.