Narrative:

All ground operations were normal. We were cleared for takeoff. After takeoff; was told to contact departure. First officer switched to departure and attempted contact. Tower responded; 'you're still on tower.' we verified switch positions and tried again. Same response from tower. I instructed first officer to use radio #2. He tuned radio #2 and tried again. Tower once again responded. We told tower we may have a radio problem and to 'stand by one.' at this time we were on assigned heading 285 degrees from tower after first radio appeared not to work I engaged autoplt #1; approximately 8000 ft. I leveled at 10000 ft assigned altitude and slowed aircraft to 210 KTS in order to try and remain in tower's airspace. I requested a turn to the north to be on a downwind for runway X; the active landing runway. After checking all switches and circuit breakers; we determined radio was locked on tower frequency. I instructed first officer to call flight attendants and let them know we are returning to ZZZ -- no emergency; just a radio problem. I then told him to make a PA with same information. During this time; I coordinated with tower for a visual to runway. We were set up on downwind; slowed to 180 KTS; flaps 5 degrees. First officer now back with me; I had him enter ZZZ as destination and enter ILS and 'clean up the box.' I briefed the approach and we ran approach descent check. We then had a quick discussion to ensure we were both on the same page with the plan and had not missed anything. Gross weight was 99K. I was cleared visual and intercepted final at 9 mi. We told tower we may need them to coordination with ground and company for clearance to gate. Tower then offered a different runway and I accepted. We landed uneventfully. Once on the ground; radios again worked normal. Maintenance determined a remote air/ground sensor had failed locking the radio on the current frequency.

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Original NASA ASRS Text

Title: A B737-300 FLIGHT CREW WAS UNABLE TO SELECT ANOTHER FREQUENCY AFTER TAKEOFF ON EITHER VHF RADIO; SO THEY RETURNED TO LAND AT THEIR DEPARTURE AIRPORT.

Narrative: ALL GND OPS WERE NORMAL. WE WERE CLRED FOR TKOF. AFTER TKOF; WAS TOLD TO CONTACT DEP. FO SWITCHED TO DEP AND ATTEMPTED CONTACT. TWR RESPONDED; 'YOU'RE STILL ON TWR.' WE VERIFIED SWITCH POSITIONS AND TRIED AGAIN. SAME RESPONSE FROM TWR. I INSTRUCTED FO TO USE RADIO #2. HE TUNED RADIO #2 AND TRIED AGAIN. TWR ONCE AGAIN RESPONDED. WE TOLD TWR WE MAY HAVE A RADIO PROB AND TO 'STAND BY ONE.' AT THIS TIME WE WERE ON ASSIGNED HDG 285 DEGS FROM TWR AFTER FIRST RADIO APPEARED NOT TO WORK I ENGAGED AUTOPLT #1; APPROX 8000 FT. I LEVELED AT 10000 FT ASSIGNED ALT AND SLOWED ACFT TO 210 KTS IN ORDER TO TRY AND REMAIN IN TWR'S AIRSPACE. I REQUESTED A TURN TO THE N TO BE ON A DOWNWIND FOR RWY X; THE ACTIVE LNDG RWY. AFTER CHKING ALL SWITCHES AND CIRCUIT BREAKERS; WE DETERMINED RADIO WAS LOCKED ON TWR FREQ. I INSTRUCTED FO TO CALL FLT ATTENDANTS AND LET THEM KNOW WE ARE RETURNING TO ZZZ -- NO EMER; JUST A RADIO PROB. I THEN TOLD HIM TO MAKE A PA WITH SAME INFO. DURING THIS TIME; I COORDINATED WITH TWR FOR A VISUAL TO RWY. WE WERE SET UP ON DOWNWIND; SLOWED TO 180 KTS; FLAPS 5 DEGS. FO NOW BACK WITH ME; I HAD HIM ENTER ZZZ AS DEST AND ENTER ILS AND 'CLEAN UP THE BOX.' I BRIEFED THE APCH AND WE RAN APCH DSCNT CHK. WE THEN HAD A QUICK DISCUSSION TO ENSURE WE WERE BOTH ON THE SAME PAGE WITH THE PLAN AND HAD NOT MISSED ANYTHING. GROSS WT WAS 99K. I WAS CLRED VISUAL AND INTERCEPTED FINAL AT 9 MI. WE TOLD TWR WE MAY NEED THEM TO COORD WITH GND AND COMPANY FOR CLRNC TO GATE. TWR THEN OFFERED A DIFFERENT RWY AND I ACCEPTED. WE LANDED UNEVENTFULLY. ONCE ON THE GND; RADIOS AGAIN WORKED NORMAL. MAINT DETERMINED A REMOTE AIR/GND SENSOR HAD FAILED LOCKING THE RADIO ON THE CURRENT FREQ.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.