Narrative:

On a night VFR cross country with a foreign student, the approach controller gave us a VFR descent at our discretion from 4000 ft MSL. I told my student (who spoke only broken english) to descend to 2500 ft. Meanwhile, I looked up the tower frequency as I assumed we would be handed off soon. As I was about to tune the frequency, I noticed my student was descending lower than 2500 ft. While instructing him to maintain 2500 ft, I inadvertently tuned tower on the radio that we had been talking to approach on. When I called approach to let the controller know we would be descending to 2000 ft, I was supposed to hear tower call back. He advised me to stay with him. I clarified his instructions. In the future, I will correct my student and wait to change frequencys.

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Original NASA ASRS Text

Title: A PA34 INSTRUCTOR PLT CHANGES OVER TO ABE TWR FROM APCH CTL SOONER THAN PLANNED WHILE HE WAS INSTRUCTING HIS STUDENT REGARDING AN ALT ASSIGNMENT SW OF ABE, PA.

Narrative: ON A NIGHT VFR XCOUNTRY WITH A FOREIGN STUDENT, THE APCH CTLR GAVE US A VFR DSCNT AT OUR DISCRETION FROM 4000 FT MSL. I TOLD MY STUDENT (WHO SPOKE ONLY BROKEN ENGLISH) TO DSND TO 2500 FT. MEANWHILE, I LOOKED UP THE TWR FREQ AS I ASSUMED WE WOULD BE HANDED OFF SOON. AS I WAS ABOUT TO TUNE THE FREQ, I NOTICED MY STUDENT WAS DSNDING LOWER THAN 2500 FT. WHILE INSTRUCTING HIM TO MAINTAIN 2500 FT, I INADVERTENTLY TUNED TWR ON THE RADIO THAT WE HAD BEEN TALKING TO APCH ON. WHEN I CALLED APCH TO LET THE CTLR KNOW WE WOULD BE DSNDING TO 2000 FT, I WAS SUPPOSED TO HEAR TWR CALL BACK. HE ADVISED ME TO STAY WITH HIM. I CLARIFIED HIS INSTRUCTIONS. IN THE FUTURE, I WILL CORRECT MY STUDENT AND WAIT TO CHANGE FREQS.

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.