Narrative:

I was executing a GPS approach and made 3 position reports on the unicom frequency; including the final call during short final. An executive jet taxied to the hold short line and then; without warning and without any announcement on the unicom frequency; pulled onto the runway. He then broadcasted 'rolling runway xx with IFR departure.' this action necessitated immediate evasive action to avoid collision. Airport has an rco. I spoke to the supervising controller who checked the transcript and there was no clearance void time issued for [departing airport]; hence no urgency for him to become airborne. If this event has occurred at a towered field; other aircraft would have been cited for a runway incursion. I have never experienced such a blatant disregard for established procedures and safety in my 18 years of flying.

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Original NASA ASRS Text

Title: An executive jet departed non-tower airport while M20K aircraft was on GPS approach; causing M20K to take evasive action.

Narrative: I was executing a GPS approach and made 3 position reports on the UNICOM frequency; including the final call during short final. An executive jet taxied to the hold short line and then; without warning and without any announcement on the UNICOM frequency; pulled onto the runway. He then broadcasted 'rolling Runway XX with IFR departure.' This action necessitated immediate evasive action to avoid collision. Airport has an RCO. I spoke to the Supervising Controller who checked the transcript and there was no clearance void time issued for [departing airport]; hence no urgency for him to become airborne. If this event has occurred at a towered field; other aircraft would have been cited for a runway incursion. I have never experienced such a blatant disregard for established procedures and safety in my 18 years of flying.

Data retrieved from NASA's ASRS site as of July 2013 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.