Narrative:

Conducting pre-solo flight instruction with student pilot at snl. After completing runup/before takeoff checks; taxied to hold short line. Two other small single engine [aircraft] in right traffic pattern for runway 17. After the second airplane completed a touch and go; announced our intention to depart shawnee runway 17 remaining closed traffic. Started takeoff roll and as we became airborne spotted what appeared to be a twin cessna aircraft about 1000 feet away on the runway pointed in our direction. Since we were already airborne at an altitude of 25' and airspeed increasing; I directed the student pilot to offset to the right side of the runway. As we offset; I was unable to keep the twin cessna in sight; but we passed overhead offset at a safe altitude. As we went by; we heard the pilot of the other aircraft query if we had heard him on the radio. We had heard no calls from anyone other than the two 17's in the pattern. The airport at shawnee is not level and there is a blind spot for aircraft at either end of the runway. Not only is the visual line of sight blocked; radio transmissions are blocked as well. After conferring with other instructors who overheard the exchange; the twin cessna pilot announced his intention to back taxi on runway 17 due to the ramp being blocked by aircraft and construction equipment. We were already sitting in the run up area for 17 and didn't hear any of his transmissions and were unaware that he was on the runway. To prevent a recurrence; it might be possible to install a low power repeater that would eliminate the radio blind spot at snl. Pilots must remain vigilant at non-towered airports and be prepared for the unexpected.

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Original NASA ASRS Text

Title: An aircraft took evasive action after takeoff at SNL to avoid a light twin which just landed. Neither pilot heard the other's CTAF radio report because a hump on the Runway 17/35 blocks opposite end radio transmissions.

Narrative: Conducting pre-solo flight instruction with student pilot at SNL. After completing runup/before takeoff checks; taxied to hold short line. Two other small single engine [aircraft] in right traffic pattern for Runway 17. After the second airplane completed a touch and go; announced our intention to depart Shawnee Runway 17 remaining closed traffic. Started takeoff roll and as we became airborne spotted what appeared to be a twin Cessna aircraft about 1000 feet away on the runway pointed in our direction. Since we were already airborne at an altitude of 25' and airspeed increasing; I directed the student pilot to offset to the right side of the runway. As we offset; I was unable to keep the twin Cessna in sight; but we passed overhead offset at a safe altitude. As we went by; we heard the pilot of the other aircraft query if we had heard him on the radio. We had heard no calls from anyone other than the two 17's in the pattern. The airport at Shawnee is not level and there is a blind spot for aircraft at either end of the Runway. Not only is the visual line of sight blocked; radio transmissions are blocked as well. After conferring with other instructors who overheard the exchange; the twin Cessna pilot announced his intention to back taxi on Runway 17 due to the ramp being blocked by aircraft and construction equipment. We were already sitting in the run up area for 17 and didn't hear any of his transmissions and were unaware that he was on the runway. To prevent a recurrence; it might be possible to install a low power repeater that would eliminate the radio blind spot at SNL. Pilots must remain vigilant at non-towered airports and be prepared for the unexpected.

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.