PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Private
Flight Crew Last 90 Days 20; Flight Crew Total 900; Flight Crew Type 700
Communication Breakdown; Situational Awareness
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Flight Crew Took Evasive Action; Flight Crew Executed Go Around / Missed Approach
Human Factors
[I flew] to VNC for lunch. There was a considerable traffic load at VNC and I sequenced behind another aircraft; also via the crosswind entry. I made position calls on each leg of the pattern; and twice on the downwind leg. I turned my base leg after the aircraft in front of me passed my wing. Spacing was perfect and the aircraft in front of me landed without event. While on the base leg (landing aircraft on short final); I saw [another aircraft] taxi up in the #1 position at the hold short line. I had been watching them and they held for less than one minute (a short period; considering all the sequenced landing traffic). After I announced a 'turning base to final' call; the [other aircraft] announced their intentions to lineup and wait. I immediately said; 'Sir I am on final'. This was ignored when I saw the [other aircraft] start to move forward. I immediately queried 'What are you doing?' They did not respond. As the [other aircraft] continued to move toward the runway; I announced; 'I am on short final. Stop!' This announcement was also ignored.  Once the landing traffic cleared the runway; the [other aircraft] announced their intentions to depart (no direction specified). I estimate my altitude was 100 ft AGL at the time and since there was an immediately conflict; I announced and executed a go-around.While on the upwind leg (right side-step); I asked the [other aircraft] what their intentions were so we wouldn't have another conflict with them. This time they finally replied; and stated they were going to fly the coast line. After flying another lap in the pattern; I landed without incident. It's also worth noting that there was no other traffic behind me.This pilot's impatience; disregard for safety; failure to effectively communicate; and inability identify traffic on short final; had nearly resulted in an aviation accident at VNC yesterday.
GA pilot reported executing a last minute go-around from 100 AGL when another aircraft taxied into position on the runway at VNC.