Narrative:

I was working close to the angwin airport, ca. The field elevation there is 1848 ft. The airport is more or less the highest point in the vicinity since the airport is located on a small plateau. We were doing photo work in that area. Our job is to shoot pictures of homes. I am the pilot and I had a photographer on board. We were flying already with the left door off to allow the photographer to do his work. That caused also a lot of noise in the cockpit. We started working over the town of st helena at about XA30. We worked our way towards the angwin airport at about 1 hour later. When I arrived close to the airport, I announced on the CTAF that we would work in the area, went off the airport. The airport has a published traffic pattern which is right traffic for runway 34 and standard for runway 16. The pattern altitude is depicted with 2698 ft MSL. So the patterns are east of the airport for noise abatement. I was working west over a 'noise sensitive area.' when I announced my intentions on the CTAF, I did not see or hear anybody in the pattern or on frequency. Doing photo work means for me, flying relatively low and slow, but staying also out of the shaded areas of the ht/velocity diagram -- which I did all the time. We were already working about for 1 hour in that area, and I heard in the meantime guys talking on the radio and saw them also in the traffic pattern. They were also chattering on the radio, but I didn't pay too much attention to them since they were on the other side of the airport and I was working below their tpa anyway. We were shooting pictures of homes which were built on a steep slope, when I discovered that a C152 circled around us in a very unusual low altitude for a fixed wing aircraft. It seemed to me and my photographer that he almost wanted to attack us. In fact, he was flying very close and low toward us. That had also the effect that he forced us more or less to a lower altitude, plus he increased the noise level in that area even more. At that time, I heard him talking to the local sheriff helicopter. He told them that I was flying recklessly 10 ft over houses, which is just not true. I left the area immediately and the guy in the C152 followed us to petaluma, ca. We landed and parked the helicopter at petaluma airport (O69) on the ramp. A few mins later, I saw the cessna taxiing behind us on the taxiway. He didn't stop nor did he talk to us and then he left.

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Original NASA ASRS Text

Title: NMAC AND PROX TO GND BY A C152 WHO WAS ATTEMPTING TO OBTAIN THE N-NUMBER OF A HELI THAT WAS TAKING PHOTOS OF HOMES BELOW TPA AND TO THE W OF 2O3, CA.

Narrative: I WAS WORKING CLOSE TO THE ANGWIN ARPT, CA. THE FIELD ELEVATION THERE IS 1848 FT. THE ARPT IS MORE OR LESS THE HIGHEST POINT IN THE VICINITY SINCE THE ARPT IS LOCATED ON A SMALL PLATEAU. WE WERE DOING PHOTO WORK IN THAT AREA. OUR JOB IS TO SHOOT PICTURES OF HOMES. I AM THE PLT AND I HAD A PHOTOGRAPHER ON BOARD. WE WERE FLYING ALREADY WITH THE L DOOR OFF TO ALLOW THE PHOTOGRAPHER TO DO HIS WORK. THAT CAUSED ALSO A LOT OF NOISE IN THE COCKPIT. WE STARTED WORKING OVER THE TOWN OF ST HELENA AT ABOUT XA30. WE WORKED OUR WAY TOWARDS THE ANGWIN ARPT AT ABOUT 1 HR LATER. WHEN I ARRIVED CLOSE TO THE ARPT, I ANNOUNCED ON THE CTAF THAT WE WOULD WORK IN THE AREA, WENT OFF THE ARPT. THE ARPT HAS A PUBLISHED TFC PATTERN WHICH IS R TFC FOR RWY 34 AND STANDARD FOR RWY 16. THE PATTERN ALT IS DEPICTED WITH 2698 FT MSL. SO THE PATTERNS ARE E OF THE ARPT FOR NOISE ABATEMENT. I WAS WORKING W OVER A 'NOISE SENSITIVE AREA.' WHEN I ANNOUNCED MY INTENTIONS ON THE CTAF, I DID NOT SEE OR HEAR ANYBODY IN THE PATTERN OR ON FREQ. DOING PHOTO WORK MEANS FOR ME, FLYING RELATIVELY LOW AND SLOW, BUT STAYING ALSO OUT OF THE SHADED AREAS OF THE HT/VELOCITY DIAGRAM -- WHICH I DID ALL THE TIME. WE WERE ALREADY WORKING ABOUT FOR 1 HR IN THAT AREA, AND I HEARD IN THE MEANTIME GUYS TALKING ON THE RADIO AND SAW THEM ALSO IN THE TFC PATTERN. THEY WERE ALSO CHATTERING ON THE RADIO, BUT I DIDN'T PAY TOO MUCH ATTN TO THEM SINCE THEY WERE ON THE OTHER SIDE OF THE ARPT AND I WAS WORKING BELOW THEIR TPA ANYWAY. WE WERE SHOOTING PICTURES OF HOMES WHICH WERE BUILT ON A STEEP SLOPE, WHEN I DISCOVERED THAT A C152 CIRCLED AROUND US IN A VERY UNUSUAL LOW ALT FOR A FIXED WING ACFT. IT SEEMED TO ME AND MY PHOTOGRAPHER THAT HE ALMOST WANTED TO ATTACK US. IN FACT, HE WAS FLYING VERY CLOSE AND LOW TOWARD US. THAT HAD ALSO THE EFFECT THAT HE FORCED US MORE OR LESS TO A LOWER ALT, PLUS HE INCREASED THE NOISE LEVEL IN THAT AREA EVEN MORE. AT THAT TIME, I HEARD HIM TALKING TO THE LCL SHERIFF HELI. HE TOLD THEM THAT I WAS FLYING RECKLESSLY 10 FT OVER HOUSES, WHICH IS JUST NOT TRUE. I LEFT THE AREA IMMEDIATELY AND THE GUY IN THE C152 FOLLOWED US TO PETALUMA, CA. WE LANDED AND PARKED THE HELI AT PETALUMA ARPT (O69) ON THE RAMP. A FEW MINS LATER, I SAW THE CESSNA TAXIING BEHIND US ON THE TXWY. HE DIDN'T STOP NOR DID HE TALK TO US AND THEN HE LEFT.

Data retrieved from NASA's ASRS site as of July 2007 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.