Narrative:

I was working local control at the time. It was twilight. Sunset was at xa:25 local, incident happened at xa:55LCL. Runway 24 was active. I gave runway 24 to ground control for a runway check. Aircraft on 2 mi final runway 24. Ground control taxied BE55 out for a runway 15R departure. I put the BE55 in position runway 15R after ground control gave me runway 15R. Ground control had taxied a C172 to runway 24 intersection departure. The C172 was doing his runup on runway 15R/33L when I cleared the BE55 for takeoff. I scanned the runway, but did not see aircraft on runway. There is a pillar 'post' in window and aircraft was in blind spot. BE55 cleared C172 by about 50 ft. Ground control advised me that there was a C172 on runway after BE55 was airborne. BE55 advised me there was a C172 on runway on departure climb out. Lesson: never trust your ground control, and get off your rear end! Then scan around all obstacles! Callback conversation with reporter revealed the following information: reporter advised he only released the runway for a vehicle runway check to determine snow obstruction. Ground control did not coordination with local for the C172 usage. The cessna 'hid' behind the pole from where the reporter was sitting, alleging the cessna did not have his wing light on, which he said would have reflected off the snow off the runway edge. Runups on runways 15 at runway 24 are very frequently utilized due to the lack of taxiway runup areas adjoining the runways.

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Original NASA ASRS Text

Title: ISP GC ADVISES LCL THAT A C172 IS ON RWY 24 AFTER HEARING LCL CLR A BE55 FOR TKOF.

Narrative: I WAS WORKING LC AT THE TIME. IT WAS TWILIGHT. SUNSET WAS AT XA:25 LCL, INCIDENT HAPPENED AT XA:55LCL. RWY 24 WAS ACTIVE. I GAVE RWY 24 TO GC FOR A RWY CHK. ACFT ON 2 MI FINAL RWY 24. GC TAXIED BE55 OUT FOR A RWY 15R DEP. I PUT THE BE55 IN POSITION RWY 15R AFTER GC GAVE ME RWY 15R. GC HAD TAXIED A C172 TO RWY 24 INTXN DEP. THE C172 WAS DOING HIS RUNUP ON RWY 15R/33L WHEN I CLEARED THE BE55 FOR TKOF. I SCANNED THE RWY, BUT DID NOT SEE ACFT ON RWY. THERE IS A PILLAR 'POST' IN WINDOW AND ACFT WAS IN BLIND SPOT. BE55 CLRED C172 BY ABOUT 50 FT. GC ADVISED ME THAT THERE WAS A C172 ON RWY AFTER BE55 WAS AIRBORNE. BE55 ADVISED ME THERE WAS A C172 ON RWY ON DEP CLB OUT. LESSON: NEVER TRUST YOUR GC, AND GET OFF YOUR REAR END! THEN SCAN AROUND ALL OBSTACLES! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED HE ONLY RELEASED THE RWY FOR A VEHICLE RWY CHK TO DETERMINE SNOW OBSTRUCTION. GC DID NOT COORD WITH LCL FOR THE C172 USAGE. THE CESSNA 'HID' BEHIND THE POLE FROM WHERE THE RPTR WAS SITTING, ALLEGING THE CESSNA DID NOT HAVE HIS WING LIGHT ON, WHICH HE SAID WOULD HAVE REFLECTED OFF THE SNOW OFF THE RWY EDGE. RUNUPS ON RWYS 15 AT RWY 24 ARE VERY FREQUENTLY UTILIZED DUE TO THE LACK OF TXWY RUNUP AREAS ADJOINING THE RWYS.

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.