Narrative:

While beginning my training flight from travel city to alpena I requested permission to taxi to active runway. I received instruction to taxi to runway 18, make right turn on taxiway, follow the small aircraft Y. So I proceeded to follow the small aircraft Y. There was an small aircraft Z ahead of small aircraft Y and small aircraft west following me. The small aircraft Y and small aircraft Z stopped for run-up short of approach end of runway. I stopped a short distance behind them and proceeded to do my run-up. Forgot to change to tower frequency. The other aircraft then departed on runway 18. I then started a departure on runway 18, forgetting to wait for a clearance to take off. While still on ground control frequency. I then noticed another aircraft landing on runway 28. I then realized I departed west/O clearance for takeoff and was not on tower frequency. The aircraft on final for 28 then did a go around. The ground controller then informed me that I just departed west/O a takeoff clearance. The controller then asked for my full north # of aircraft and my base location. I informed the controller that I was aware of my error. I then proceeded on course to alpena.

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Original NASA ASRS Text

Title: GA SMA UNAUTH TKOF FORCES ANOTHER ACFT LNDG ON A CROSSING RWY TO GO AROUND.

Narrative: WHILE BEGINNING MY TRNING FLT FROM TRAVEL CITY TO ALPENA I REQUESTED PERMISSION TO TAXI TO ACTIVE RWY. I RECEIVED INSTRUCTION TO TAXI TO RWY 18, MAKE RIGHT TURN ON TXWY, FOLLOW THE SMA Y. SO I PROCEEDED TO FOLLOW THE SMA Y. THERE WAS AN SMA Z AHEAD OF SMA Y AND SMA W FOLLOWING ME. THE SMA Y AND SMA Z STOPPED FOR RUN-UP SHORT OF APCH END OF RWY. I STOPPED A SHORT DISTANCE BEHIND THEM AND PROCEEDED TO DO MY RUN-UP. FORGOT TO CHANGE TO TWR FREQ. THE OTHER ACFT THEN DEPARTED ON RWY 18. I THEN STARTED A DEP ON RWY 18, FORGETTING TO WAIT FOR A CLRNC TO TAKE OFF. WHILE STILL ON GND CTL FREQ. I THEN NOTICED ANOTHER ACFT LNDG ON RWY 28. I THEN REALIZED I DEPARTED W/O CLRNC FOR TKOF AND WAS NOT ON TWR FREQ. THE ACFT ON FINAL FOR 28 THEN DID A GO AROUND. THE GND CTLR THEN INFORMED ME THAT I JUST DEPARTED W/O A TKOF CLRNC. THE CTLR THEN ASKED FOR MY FULL N # OF ACFT AND MY BASE LOCATION. I INFORMED THE CTLR THAT I WAS AWARE OF MY ERROR. I THEN PROCEEDED ON COURSE TO ALPENA.

Data retrieved from NASA's ASRS site as of August 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.