Narrative:

Ground control taxied the C414 to runway 7L and changed him to my frequency on local control. I had some tight traffic landing and departing runway 1L and decided to wait to talk to the C414 until I had a better opportunity to roll him. I had one particularly tight gap shot on 1L and told a EMB145 who was holding in position on 1L to come up on the power and be ready for an immediate takeoff. As soon as the previous arrival taxied clear of runway 1L I cleared the EMB145 for an immediate takeoff. After listening to the tapes; I realized I was talking fast but I clearly said the call sign correctly. The C414 captain took this immediate take off to be his; and read it back very quickly omitting the runway of departure and without using his full call sign. The EMB145 crew then comes on frequency and reads back cleared for takeoff. It didn't click immediately but something made me look over to the C414 and I saw him turning the corner of runway 7L and starting his takeoff roll; at which point I stopped him and instructed him to hold in position.when I am working a single runway operation as is the normal thing here at mke; I tend to talk fast as a way to instill urgency in the pilots when the final is full and I need them to move fast. Perhaps the C414 pilot had trouble understanding my transmission so I will try to be more conscious of my rate of speech. It is also easy to miss read backs such as this one when everyone is talking fast and you feel like everyone is on the same page. That being said; the pilot should have clarified if he was unsure if the last transmission was for him; because it clearly was not.

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Original NASA ASRS Text

Title: C414 pilot holding short of Runway 7L at MKE accepted a takeoff clearance meant for an EMB145 in position on Runway 1L. The Tower Controller detects the C414 entering the runway and stops his takeoff.

Narrative: Ground control taxied the C414 to Runway 7L and changed him to my frequency on Local Control. I had some tight traffic landing and departing Runway 1L and decided to wait to talk to the C414 until I had a better opportunity to roll him. I had one particularly tight gap shot on 1L and told a EMB145 who was holding in position on 1L to come up on the power and be ready for an immediate takeoff. As soon as the previous arrival taxied clear of Runway 1L I cleared the EMB145 for an immediate takeoff. After listening to the tapes; I realized I was talking fast but I clearly said the call sign correctly. The C414 Captain took this immediate take off to be his; and read it back very quickly omitting the runway of departure and without using his full call sign. The EMB145 crew then comes on frequency and reads back cleared for takeoff. It didn't click immediately but something made me look over to the C414 and I saw him turning the corner of Runway 7L and starting his takeoff roll; at which point I stopped him and instructed him to hold in position.When I am working a single runway operation as is the normal thing here at MKE; I tend to talk fast as a way to instill urgency in the pilots when the final is full and I need them to move fast. Perhaps the C414 pilot had trouble understanding my transmission so I will try to be more conscious of my rate of speech. It is also easy to miss read backs such as this one when everyone is talking fast and you feel like everyone is on the same page. That being said; the pilot should have clarified if he was unsure if the last transmission was for him; because it clearly was not.

Data retrieved from NASA's ASRS site as of April 2012 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.