SA 365 Dauphin 2
Conflict NMAC
Flight Crew Took Evasive Action
Airport; Environment - Non Weather Related; Procedure
We were returning to ACV with a second MH-65C approximately 3 NM in trail. As the first aircraft approached Trinidad Head; a large rock outcropping 6 NM NW of ACV; the PM transmitted their current position and altitude of 600 AGL and intentions to land on CTAF. Shortly thereafter; the PF made a slight left turn around Trinidad Head and noticed a small; low wing; single engine aircraft less than a quarter of a mile off the MH-65C's 12 o'clock position. The PF called out the traffic to the crew; announced intent to make a descending right turn; reduced power; and made a smooth 10-20 AOB turn to avoid the oncoming aircraft. Simultaneously; the PM warned the second MH-65C (still in trail) of the oncoming traffic to avoid a second incident. The general aviation aircraft passed to the left and above the MH65C within an estimated separation of 225 FT. The general aviation aircraft was not observed taking any evasive maneuvers.Additional Findings and Corrective Actions Taken:1. TCAS did not display the target; nor did it provide a traffic alert. During preflight checks; the TCAS tested properly with no deficiencies. It is suspected that the general aviation aircraft was not equipped with an operating transponder.2. No radio calls were heard over the ACV CTAF from the general aviation aircraft. The MH-65C was monitoring the ACV CTAF within 10 NM of the field in accordance with section 4-1-9 of the AIM. Additionally; the ARC210 was tested and found to be fully operational and configured properly. It is suspected that the general aviation aircraft was not utilizing or monitoring the ACV CTAF.3. A transmission was heard on ACV CTAF just prior to the mishap of an aircraft on short final to Runway 32. It was confirmed later that this was not the aircraft involved in the mishap. There were two separate general aviation aircraft in the terminal area at the time of the mishap.13. Recommendations: It is unknown if the general aviation aircraft involved in this mishap is a locally based aircraft or an aircraft transiting the area. However; as members of the local Pilot's Association; we intend to discuss this mishap with the civilian pilots who operate in and around the local area to make them more aware of locations where they may likely encounter a CG aircraft.
A helicopter suffered an NMAC with a Bonanza in the vicinity of ACV airport. The Bonanza pilot's suspected failure to utilize CTAF for position reporting was cited as a contributing factor by the reporter.