Narrative:

I was conducting a VFR; aerial mapping mission approximately 30 NM east of ZZZ airport at 3700 feet AGL (4;000 MSL); and receiving VFR advisories. I was flying southbound on a precisely mapped aerial mapping line and was informed by approach control of an IFR aircraft approximately 20 NM south of my position at 4;000 feet and was advised to climb to a higher altitude. I informed the controller that to do so would require me to turn around and start all over again. At that point the controller told me that a 10 degree turn to the right would resolve the conflict. I tried to explain to ATC that that would have the same effect as climbing. I told the camera operator sitting in the back of the aircraft to turn off the camera and we both started looking for the aircraft as I continued to try and negotiate with the controller for the impending turn back to start the line over.I believe I was asked by the controller to turn left to a heading of 090. As I was beginning to turn left I then instructed by ATC to climb to 4;500 and as I prepared to climb my operator; who had the aircraft in sight told me; do not climb! I looked up and to the right and saw the IFR; GA aircraft approximately 400-500 feet above my aircraft heading north and I told the controller that I was not going to climb due to the aircraft proximity above me. Apparently the IFR; GA aircraft had climbed to a higher altitude and the controller did not realize that at the moment he asked me to climb.later during the flight I was given a phone number to call and told that I was subject to a possible ATC deviation.contributing factor: my attempt to negotiate with the controller in an attempt to break off the line and turn around and start over again and the ATC's failure to vector the IFR GA aircraft in a manner that would have solved the conflict. In this case; the IFR aircraft was given priority and was not asked to turn or climb (that I recall) and the VFR aircraft (me) was asked to turn or climb to solve the conflict. Also contributing to the scenario was the IFR aircraft's climb to a higher altitude and the controller not knowing that he had done so.contributing factor: aerial mapping is a very precise operation; requiring the aircraft be flown at exact GPS altitudes; not MSL altitudes that align with the hemispherical cruising altitude rules. My company has a FAA waiver to deviate from the recommended VFR cruising altitudes due to the nature of aerial mapping operations. This is what set up a southbound VFR aircraft at 3;700 AGL (4;000) MSL up for a potential conflict with an aircraft traveling northbound at 4;000 MSL.contributing factor: the VFR aircraft (me) was not in controlled airspace and was only receiving ATC advisories. It is left to the PIC (me) of the VFR aircraft to ultimately decide how to handle traffic conflict resolution (aim).this was an unfortunate situation that could have had tragic consequences. For my part I should have just accepted the early climb or vector and not thought so much about the cost of having to discard good data and turn around and start the line all over again. Clearly the loss of time and money was a factor. I will not make that mistake again.as for the controller; he may or may not have understood that I was operating a commercial; revenue generating flying operation and choose to vector (give priority) to the IFR; general aviation aircraft. While I understand that ATC's main mission is to control and separate IFR traffic it is also clear to me that flying is never that simple. A GA; non-revenue IFR aircraft given priority over a commercial VFR aircraft in uncontrolled airspace and in VFR conditions simply because the IFR aircraft is on an IFR flight does not make sense to me in this situation.I think the key take away here is that when both parties (ATC and pilots) stick to their priorities and do not think clearly; then safety can be compromised and fortunately this event didnot end up a statistic on a government chart.

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Original NASA ASRS Text

Title: Twin Cessna Captain reported reluctance to accept ATC instructions to separate from IFR traffic while operating VFR on an aerial mapping mission which resulted in the IFR aircraft taking evasive action.

Narrative: I was conducting a VFR; Aerial Mapping mission approximately 30 NM East of ZZZ airport at 3700 feet AGL (4;000 MSL); and receiving VFR advisories. I was flying Southbound on a precisely mapped aerial mapping line and was informed by Approach control of an IFR aircraft approximately 20 NM South of my position at 4;000 feet and was advised to climb to a higher altitude. I informed the controller that to do so would require me to turn around and start all over again. At that point the controller told me that a 10 degree turn to the right would resolve the conflict. I tried to explain to ATC that that would have the same effect as climbing. I told the camera operator sitting in the back of the aircraft to turn off the camera and we both started looking for the aircraft as I continued to try and negotiate with the controller for the impending turn back to start the line over.I believe I was asked by the controller to turn left to a heading of 090. As I was beginning to turn left I then instructed by ATC to climb to 4;500 and as I prepared to climb my operator; who had the aircraft in sight told me; Do not climb! I looked up and to the right and saw the IFR; GA aircraft approximately 400-500 feet above my aircraft heading North and I told the controller that I was not going to climb due to the aircraft proximity above me. Apparently the IFR; GA aircraft had climbed to a higher altitude and the controller did not realize that at the moment he asked me to climb.Later during the flight I was given a phone number to call and told that I was subject to a possible ATC deviation.Contributing factor: My attempt to negotiate with the controller in an attempt to break off the line and turn around and start over again and the ATC's failure to vector the IFR GA aircraft in a manner that would have solved the conflict. In this case; the IFR aircraft was given priority and was not asked to turn or climb (that I recall) and the VFR aircraft (me) was asked to turn or climb to solve the conflict. Also contributing to the scenario was the IFR aircraft's climb to a higher altitude and the controller not knowing that he had done so.Contributing factor: Aerial Mapping is a very precise operation; requiring the aircraft be flown at exact GPS altitudes; not MSL altitudes that align with the hemispherical cruising altitude rules. My company has a FAA waiver to deviate from the recommended VFR cruising altitudes due to the nature of aerial mapping operations. This is what set up a southbound VFR aircraft at 3;700 AGL (4;000) MSL up for a potential conflict with an aircraft traveling northbound at 4;000 MSL.Contributing factor: The VFR aircraft (me) was not in controlled airspace and was only receiving ATC advisories. It is left to the PIC (me) of the VFR aircraft to ultimately decide how to handle traffic conflict resolution (AIM).This was an unfortunate situation that could have had tragic consequences. For my part I should have just accepted the early climb or vector and not thought so much about the cost of having to discard good data and turn around and start the line all over again. Clearly the loss of time and money was a factor. I will not make that mistake again.As for the controller; he may or may not have understood that I was operating a commercial; revenue generating flying operation and choose to vector (give priority) to the IFR; General Aviation aircraft. While I understand that ATC's main mission is to control and separate IFR traffic it is also clear to me that flying is never that simple. A GA; non-revenue IFR aircraft given priority over a commercial VFR aircraft in uncontrolled airspace and in VFR conditions simply because the IFR aircraft is on an IFR flight does not make sense to me in this situation.I think the key take away here is that when both parties (ATC and pilots) stick to their priorities and do not think clearly; then safety can be compromised and fortunately this event didnot end up a statistic on a government chart.

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.