SMA AND MLG POTENTIAL CONFLICT.

Narrative

DUAL XC TRNING. ROUTE OF FLT FROM HAMILTON FIELD; CA; TO MC CLELLAN AFB USING COMBO OF PILOTAGE AND VOR NAV. CONTACTED TRAVIS APCH CTL AT NAPA (SKAGGS ISLAND VOR) FOR VFR FLT FOLLOWING THROUGH TRAVIS AIRSPACE AND FOR HDOF TO SACRAMENTO TRACON FOR ARSA SVCS AROUND SACRAMENTO METRO AND MC CLELLAN AFB ARSA'S. WE WERE AT AND MAINTAINED 3500' MSL FROM INITIAL CONTACT TO THE TIME OF THE INCIDENT. FLT FOLLOWING WAS NORMAL AND HDOFS ALSO; TILL THE LAST ONE. APCH CTLR WAS RELAYING A CLRNC AND TOLD US TO STANDBY. CTLR ISSUED TFC NOTICES TO AN ACR COMPANY REGARDING A LIGHT ACFT EBND AT 2500'. WE (STUDENT AND CFI) HAD VISUAL ON AN MLG OFF METRO CLBING; MARKINGS UNKNOWN. BEARING REMAINED CONSTANT INDICATING POTENTIAL FOR COLLISION. I EXPECTED THE DEPARTING AIRPLANE TO TURN EWARD (AS USUAL). WHEN THE RANGE CLOSED TO LESS THAN A MILE; I REDUCED PWR AND BEGAN DSCNT. AT ABOUT THE SAME TIME THE MLG SAW ME AND TURNED TO HIS RIGHT. AT ABOUT THAT TIME CTLR REQUESTED I VERIFY ALT 2500' (ACFT IS NOT MODE C EQUIPPED). I NOTIFIED HIM WE HAD BEEN AT 3500' AND WERE CURRENTLY DSNDING. THE MLG WAS CALLED AS TFC AND THERE WAS SOME DISCUSSION BTWN THE CTLR; THE ACR PLT AND MYSELF REGARDING WHY THAT HAD HAPPENED. ON THE LAST HDOF THE CTLR WAS BUSY. THERE WAS CONFUSION AS TO OUR ALT; ALTHOUGH IT HAD BEEN STEADY FOR THE PROCEEDING 50 MI OF FLT. THE RADIO WAS RPTED BROKEN BY THAT CTLR; ALTHOUGH NO OTHER ATC FAC HAD RPTED THIS TO ME. DSCNT WAS CONTINUED AND ACFT WAS LANDED WITH NO FURTHER INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: ACFT WAS FROM MIL AERO CLUB THUS USING MIL FACS; BUT CIVILIAN ACTIVITY. ON CONTACT AT EACH HDOF PLT GAVE ALT OF 3500'. NO OTHER CTLR HAD INDICATED ANY COM EQUIP PROB.