Narrative:

Fnl winds were 100 at 9. SCT075 BKN100. Storm cells in the area and I am expecting winds to shift south. No traffic seen or heard I taxi my cessna from the hangar via taxiway alpha to runway 15. On taxiway alpha made radio call 'noco traffic cessna taxi to 15; noco.' run-up. Made 360 degree turn in run-up area looking all quadrants for traffic. No traffic seen. No traffic heard on radio. Made radio call 'noco traffic cessna departing 15 noco.' nothing heard. Taxi onto runway 15 and take-off. The opposite direction 33 run-up area is not visible from the 15 departure area. Upon becoming airborne I see another aircraft on takeoff opposite direction on runway 33 still 6;000 ft away. It probably took me at least 4 seconds staring to confirm to me that another aircraft was taking off opposite direction and it wasn't a car on the road behind or something else happening. I side-step to the right on the upwind pattern leg side 300 ft off the runway and continue climbing keeping my eye on the other aircraft. The other aircraft and I then make radio communication with each other. We had seen each other at the same time. They aborted take-off on the runway and taxied to runway 15 as other traffic had heard my 15 calls and had entered the pattern for 15 by this time.the runway has a hump in it and the two departure ends are not visible on the ground from each other. Communication antennas are on the aircraft bottom perhaps contributing to lack of hearing each other on the radio. I side-stepped as soon as I spotted the other aircraft still a mile in away in front of me but of course being opposite direction we do pass each other. After initial sighting I never lost sight of them. Both of us confirmed that we had made radio calls before departure but neither of us had heard the other. I expect their report to be the same and opposite to mine.

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Original NASA ASRS Text

Title: Cessna pilot reported a NMAC with opposite direction aircraft during takeoff roll from a non-towered airport.

Narrative: FNL winds were 100 at 9. SCT075 BKN100. Storm cells in the area and I am expecting winds to shift south. No traffic seen or heard I taxi my Cessna from the hangar via taxiway Alpha to Runway 15. On taxiway Alpha made radio call 'Noco Traffic Cessna taxi to 15; Noco.' Run-up. Made 360 degree turn in run-up area looking all quadrants for traffic. No traffic seen. No traffic heard on radio. Made radio call 'Noco Traffic Cessna departing 15 Noco.' Nothing heard. Taxi onto runway 15 and take-off. The opposite direction 33 run-up area is not visible from the 15 departure area. Upon becoming airborne I see another aircraft on takeoff opposite direction on runway 33 still 6;000 ft away. It probably took me at least 4 seconds staring to confirm to me that another aircraft was taking off opposite direction and it wasn't a car on the road behind or something else happening. I side-step to the right on the upwind pattern leg side 300 ft off the runway and continue climbing keeping my eye on the other aircraft. The other aircraft and I then make radio communication with each other. We had seen each other at the same time. They aborted take-off on the runway and taxied to runway 15 as other traffic had heard my 15 calls and had entered the pattern for 15 by this time.The runway has a hump in it and the two departure ends are not visible on the ground from each other. Communication antennas are on the aircraft bottom perhaps contributing to lack of hearing each other on the radio. I side-stepped as soon as I spotted the other aircraft still a mile in away in front of me but of course being opposite direction we do pass each other. After initial sighting I never lost sight of them. Both of us confirmed that we had made radio calls before departure but neither of us had heard the other. I expect their report to be the same and opposite to mine.

Data retrieved from NASA's ASRS site 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.