TCA; ARSA PENETRATION WITHOUT CLRNC.

Narrative

WE DEPARTED COLLEGE PARK ARPT IN AN SMA. A STUDENT PLT WAS FLYING FROM THE FRONT LEFT SEAT. A FLT INSTRUCTOR WAS SITTING IN THE FRONT RIGHT SEAT. I WAS SITTING IN THE REAR RIGHT SEAT. ALL 3 PLTS WERE USING A HEADSET AND INTERCOM. I HAD A MIC IN THE REAR SEAT AND TRIED TO OBTAIN A CLRNC WITH BWI APCH. BWI INSTRUCTED ME TO CALL ANDREWS. I CALLED ANDREWS RADAR; ASKED FOR CLRNC TO SALISBURY. ANDREWS INSTRUCTED ME TO CALL DCA APCH. I CALLED DCA APCH TWICE WITH NO RESPONSE. AFTER TRYING TO CALL DCA APCH THE SECOND TIME; I NOTICED THE ALTIMETER READING 3000' AND SUGGESTED WE DSND. THE INTERCOM WAS WEAK DUE TO A LOW BATTERY AND COM WITH THE STUDENT PLT AND INSTR IN THE FRONT SEAT WAS DIFFICULT. APPARENTLY THE STUDENT AND INSTR FLYING THE ACFT ASSUMED I HAD OBTAINED PERMISSION TO ENTER THE ARSA. THE FLT PATH AFTER DEPARTING COLLEGE PARK WAS AN EASTERLY HDG CLBING TO 3000' MSL. WE INADVERTENTLY VIOLATED THE ARSA AND POSSIBLY THE NORTHERN BOUNDARY OF THE DCA TCA DUE TO POOR PREFLT NAV PLANNING AND POOR INFLT COMS. I HAD VOLUNTEERED TO DO RADIO COMS TO REDUCE PLT WORKLOAD AND FREE THE INSTR IN THE FRONT SEAT TO TEACH THE STUDENT PLT. WE FLEW TO OCEAN CITY; MD; EASTON; MD; AND FREDRICK; MD; W/O FURTHER INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: INTERCOM WORKED WELL PRIOR TO DEP BUT RPTR AWARE THAT BATTERIES WEAR DOWN RAPIDLY. NO TIME TO CHANGE N FLT UNDER THESE CIRCUMSTANCES ANYWAY. RPTR NORMALLY DOES NOT CONTACT WASHINGTON APCH BECAUSE OF DELAYS AND DIFFICULTY EVEN GETTING ON FREQ. USUALLY USES ANDREWS AND RECEIVES GOOD SVC THROUGH AREA. CONTACTED BWI APCH BECAUSE INITIAL HDG WAS N.