Narrative:

Had just broken VFR on a night flight. We were in communication with the approach controller who issued us a lower altitude (4000 ft) and a vector towards our destination (about 25 mi away). At the time we were flying in (or about to enter) class B airspace. The passenger in the right seat was also an IFR-rated pilot so he was helping with some of the radio selection. We switched #2 communication to listen to the ATIS destination while still using #1 communication as a primary. When we switched away from the ATIS, my 'copilot' inadvertently moved the speaker/phone selector to the middle (neither speaker nor phone) position. In the dark cockpit this was not visible. We briefed the approach (although VFR), but heard no further instruction from the approach controller. After 2-3 mins I felt something was wrong and transmitted on both radios, only to find out that they were apparently inoperative. We then contacted the approach facility on our handheld radio. We were told that they had been trying to reach us for 10 mi. We were issued 2300 ft and subsequently cleared to land. While all this was going on I kept trouble-shooting the radios. When taxiing clear of the runway I found the selector toggled in the middle position. Suggestions: allow others to select radios only if they are very familiar with the particular setup. The manufacturer should eliminate the middle (dead) toggle position on the selector. It should always be either on speaker or phone.

Google
 

Original NASA ASRS Text

Title: LOSS OF RADIO CONTACT - PLT TECHNIQUE COM.

Narrative: HAD JUST BROKEN VFR ON A NIGHT FLT. WE WERE IN COM WITH THE APCH CTLR WHO ISSUED US A LOWER ALT (4000 FT) AND A VECTOR TOWARDS OUR DEST (ABOUT 25 MI AWAY). AT THE TIME WE WERE FLYING IN (OR ABOUT TO ENTER) CLASS B AIRSPACE. THE PAX IN THE R SEAT WAS ALSO AN IFR-RATED PLT SO HE WAS HELPING WITH SOME OF THE RADIO SELECTION. WE SWITCHED #2 COM TO LISTEN TO THE ATIS DEST WHILE STILL USING #1 COM AS A PRIMARY. WHEN WE SWITCHED AWAY FROM THE ATIS, MY 'COPLT' INADVERTENTLY MOVED THE SPEAKER/PHONE SELECTOR TO THE MIDDLE (NEITHER SPEAKER NOR PHONE) POS. IN THE DARK COCKPIT THIS WAS NOT VISIBLE. WE BRIEFED THE APCH (ALTHOUGH VFR), BUT HEARD NO FURTHER INSTRUCTION FROM THE APCH CTLR. AFTER 2-3 MINS I FELT SOMETHING WAS WRONG AND XMITTED ON BOTH RADIOS, ONLY TO FIND OUT THAT THEY WERE APPARENTLY INOP. WE THEN CONTACTED THE APCH FACILITY ON OUR HANDHELD RADIO. WE WERE TOLD THAT THEY HAD BEEN TRYING TO REACH US FOR 10 MI. WE WERE ISSUED 2300 FT AND SUBSEQUENTLY CLRED TO LAND. WHILE ALL THIS WAS GOING ON I KEPT TROUBLE-SHOOTING THE RADIOS. WHEN TAXIING CLR OF THE RWY I FOUND THE SELECTOR TOGGLED IN THE MIDDLE POS. SUGGESTIONS: ALLOW OTHERS TO SELECT RADIOS ONLY IF THEY ARE VERY FAMILIAR WITH THE PARTICULAR SETUP. THE MANUFACTURER SHOULD ELIMINATE THE MIDDLE (DEAD) TOGGLE POS ON THE SELECTOR. IT SHOULD ALWAYS BE EITHER ON SPEAKER OR PHONE.

Data retrieved from NASA's ASRS site as of July 2007 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.