Cessna 170
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 30; Flight Crew Total 2500; Flight Crew Type 700
Communication Breakdown
Conflict NMAC
Flight Crew Took Evasive Action
Procedure; Human Factors
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.
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.