Narrative:

Approximately 20 miles north of uki at 7;500 ft I contacted oakland approach and requested VFR flight following en route to sts. Approach gave me a squawk but did not follow up with a verification of radar contact; (location; altimeter setting and altitude) or any other transmission but he seemed occupied with other aircraft and I was in a remote area with rarely any traffic. (I know I should have called him to verify radar contact and altimeter setting). I monitored the frequency and when I heard an sts altimeter given to another aircraft; I adjusted my altimeter setting; I seem to recall it was 30.08. During my descent into sts on the 332 radial approximately 15 miles out; I was passing through 4;650 ft and noticed a helicopter at my 11:30 and approximately 400 ft ahead and 50 ft below. I made a 10 degree turn to the right and the helicopter made the same maneuver. I believe we passed 300 ft lateral and 50 ft vertical. The helicopter was red and white and I am very sure it was an ec-135. Approach was busy talking to another aircraft but when there was a break I asked approach if he had seen the helicopter that I just passed. Approach said 'I did; but it was too late to say anything when I saw it; I apologize.' I then heard another aircraft that I assume must have been the helicopter say on the radio 'do you mean the helicopter that was at the proper VFR altitude for his direction of flight; 4;500 ft?'I transmitted 'the cessna was descending through that altitude enroute to santa rosa.' approach then asked if I had sts in sight. I replied that I did and approach said 'contact tower 118.5 and squawk VFR.' I then listened to ATIS for sts; contacted tower and landed.

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Original NASA ASRS Text

Title: A C-170 pilot suffered an NMAC with a Eurocopter while descending for an approach to STS while utilizing flight following. A busy Controller's inability to provide timely traffic information was a contributing factor.

Narrative: Approximately 20 miles north of UKI at 7;500 FT I contacted Oakland Approach and requested VFR flight following en route to STS. Approach gave me a squawk but did not follow up with a verification of radar contact; (location; altimeter setting and altitude) or any other transmission but he seemed occupied with other aircraft and I was in a remote area with rarely any traffic. (I know I should have called him to verify radar contact and altimeter setting). I monitored the frequency and when I heard an STS altimeter given to another aircraft; I adjusted my altimeter setting; I seem to recall it was 30.08. During my descent into STS on the 332 radial approximately 15 miles out; I was passing through 4;650 FT and noticed a helicopter at my 11:30 and approximately 400 FT ahead and 50 FT below. I made a 10 degree turn to the right and the helicopter made the same maneuver. I believe we passed 300 FT lateral and 50 FT vertical. The helicopter was red and white and I am very sure it was an EC-135. Approach was busy talking to another aircraft but when there was a break I asked Approach if he had seen the helicopter that I just passed. Approach said 'I did; but it was too late to say anything when I saw it; I apologize.' I then heard another aircraft that I assume must have been the helicopter say on the radio 'do you mean the helicopter that was at the proper VFR altitude for his direction of flight; 4;500 FT?'I transmitted 'the Cessna was descending through that altitude enroute to Santa Rosa.' Approach then asked if I had STS in sight. I replied that I did and Approach said 'Contact Tower 118.5 and squawk VFR.' I then listened to ATIS for STS; contacted Tower and landed.

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.