My instructor made "request right closed traffic..." call before practicing a series of landings. Just wondering, what is the difference between this request and a "stay in the pattern..." request? Which one should I use when?
Actually, "stay in the pattern" is non-standard phraseology and shouldn't be used, even though it means the same thing as "closed traffic".
Specifying the direction isn't required but it is a good idea to ensure that everybody is thinking the same thing.
The recommended phraseology depends on the airport. If it's tower controlled then you're encouraged to use ATC's phraseology per JO 7110.65V (3−10−11):
PHRASEOLOGY− LEFT/RIGHT (if required) CLOSED TRAFFIC APPROVED. REPORT (position if required),
For uncontrolled airports we see this in the AIM (4-1-5):
Recommended UNICOM phraseologies:
(b) Outbound PHRASEOLOGY− FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO FOXTROT DEPARTING RUNWAY ONE NINER. “REMAINING IN THE PATTERN” OR “DEPARTING THE PATTERN TO THE (direction) (as appropriate)” FREDERICK.
Successive operations involving takeoffs and landings or low approaches where the aircraft does not exit the traffic pattern are defined in both JO 7110.65V and the AIM as Closed Traffic. However, the recommended phraseology for UNICOM is to say "remaining in the pattern", whereas for towered operations ATC will always use "Closed Traffic". In practice, pilots and ATC will know what you mean either way.