"Turning to ALPA’s other question, if a flightcrew member is not on a rest period, the certificate holder may contact the flightcrew member to schedule a flight assignment. However, pursuant to § 117.25(b) and (e), the certificate holder would then need to provide that flightcrew member with the requisite rest period prior to beginning the FDP. The certificate holder would also have to follow the FDP notification requirements of longcall reserve, as this type of contact and FDP assignment would qualify as longcall reserve pursuant to the definition of that term in § 117.3"


So according to the FAA a JA would be considered a long call reserve assignment thus requiring 10 hours of rest between the call and start of FDP.