Narrative:

While building night proficiency, I entered sgr airspace from north (iws airport). I was cleared for a stop-and-go landing (touch-and-goes not allowed at night at sgr). I had completed 1 landing and was on downwind for second stop-and- go. I was told to expedite landing due to traffic which was on missed approach for the ILS runway 35. I landed long, which caused me to stop 3/4 of the way down the 5000 ft usable length of the runway. I decided to err on the side of caution and asked tower's permission to taxi back to the active. Permission was granted. While taxiing back to approach end of runway 35, tower suggested departure at taxiway B which would provide plenty of runway. I responded that I would accept the 'B departure.' I taxied onto the runway and departed for my next circuit. While climbing out, the tower controller suggested that in the future I might wait for a takeoff clearance. I apologized, and stated that I had misunderstood his suggestion as a clearance. He stated that since no other aircraft were landing, no harm was done. I feel that I erred in several respects. Since I had been cleared several times for stop-and-goes, I assumed that the controller's suggestion of departure from the intersection was a takeoff clearance. Also, my use of nonstandard phraseology, 'B departure' probably added confusion to the situation. I took the controller's lack of response to my acknowledgement as a clearance onto the active (a dumb assumption). In the future, I will not assume that the lack of a clearance (or response) constitutes a clearance!

Related reports:

Google
 

Original NASA ASRS Text

Title: PLT OF AN SMA SEL TOOK OFF WITHOUT CLRNC DUE TO DISTR OF THE ROUTING OF PREVIOUS STOP-AND-GO LNDGS AND TKOFS.

Narrative: WHILE BUILDING NIGHT PROFICIENCY, I ENTERED SGR AIRSPACE FROM N (IWS ARPT). I WAS CLRED FOR A STOP-AND-GO LNDG (TOUCH-AND-GOES NOT ALLOWED AT NIGHT AT SGR). I HAD COMPLETED 1 LNDG AND WAS ON DOWNWIND FOR SECOND STOP-AND- GO. I WAS TOLD TO EXPEDITE LNDG DUE TO TFC WHICH WAS ON MISSED APCH FOR THE ILS RWY 35. I LANDED LONG, WHICH CAUSED ME TO STOP 3/4 OF THE WAY DOWN THE 5000 FT USABLE LENGTH OF THE RWY. I DECIDED TO ERR ON THE SIDE OF CAUTION AND ASKED TWR'S PERMISSION TO TAXI BACK TO THE ACTIVE. PERMISSION WAS GRANTED. WHILE TAXIING BACK TO APCH END OF RWY 35, TWR SUGGESTED DEP AT TXWY B WHICH WOULD PROVIDE PLENTY OF RWY. I RESPONDED THAT I WOULD ACCEPT THE 'B DEP.' I TAXIED ONTO THE RWY AND DEPARTED FOR MY NEXT CIRCUIT. WHILE CLBING OUT, THE TWR CTLR SUGGESTED THAT IN THE FUTURE I MIGHT WAIT FOR A TKOF CLRNC. I APOLOGIZED, AND STATED THAT I HAD MISUNDERSTOOD HIS SUGGESTION AS A CLRNC. HE STATED THAT SINCE NO OTHER ACFT WERE LNDG, NO HARM WAS DONE. I FEEL THAT I ERRED IN SEVERAL RESPECTS. SINCE I HAD BEEN CLRED SEVERAL TIMES FOR STOP-AND-GOES, I ASSUMED THAT THE CTLR'S SUGGESTION OF DEP FROM THE INTXN WAS A TKOF CLRNC. ALSO, MY USE OF NONSTANDARD PHRASEOLOGY, 'B DEP' PROBABLY ADDED CONFUSION TO THE SIT. I TOOK THE CTLR'S LACK OF RESPONSE TO MY ACKNOWLEDGEMENT AS A CLRNC ONTO THE ACTIVE (A DUMB ASSUMPTION). IN THE FUTURE, I WILL NOT ASSUME THAT THE LACK OF A CLRNC (OR RESPONSE) CONSTITUTES A CLRNC!

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.