ITCS is a Senior Chief Information Systems Technician (rate/rank read Information Technician Chief Senior). IT's are responsible for a variety of systems, from computer networks to communications systems. The former Radioman rate was combined into the IT rate several years ago.
Possibly a Flight Engineer
I haven't heard that term when relating to the US Navy. But in the Royal Navy SDG is a scubadiver
Yes. The Enlisted rate for medical personnel in the Navy is Hospital Corpsman (HM)
MOS would be most interchangeable with Rate in the navy. Rate is pretty much another word for job specialty as is mos. Rate may also be referred to as a NEC.
US $ 4.75 billion
This is called a "rating" in the Navy. The AT denotes that person's rate, or job. In this case, it is an Aviation Technician. The 3 denotes that person's rank, which in this case, is a 3rd Class Petty Officer.
"Rate" refers to a non commissioned member of the US Navy.
1949
submersible boat
SEa Air and Land
Not SSK3c, but SK3c is the old rate designation for Ship's Storekeeper, 3rd Class. The Storekeeper rate, one of the oldest in the Navy, has always used the designator SK. Today the rate/rank would be designated SK3.
Landing Helicopter Assault