Date: 202010
Local time of day: 0601-1200
Location: OKB.Airport, CA
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Descent
Airspace: Class E ZLA
ATC / advisory: CTAF OKB
Second aircraft: Small Transport
Reporter organization: Personal
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Commercial
Human factors: Communication Breakdown; Situational Awareness; Time Pressure
Anomaly: Conflict NMAC
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: On date; a midair collision between an Aircraft X; and an Aircraft Y; was narrowly avoided. At the time of the incident; conditions were VFR - visibility of approximately 10 SM or greater with no cloud cover.The Aircraft X was returning to the Oceanside Municipal Airport; OKB; from ZZZ. Aircraft X received VFR flight following from SoCal Approach; flight following was canceled as Aircraft X crossed the Oceanside VORTAC (OCN) at 3000 ft MSL. SoCal Approach requested that Aircraft X remain at or above 3000 ft MSL until OCN to remain clear of traffic in the hold at OCN. After crossing OCN at 3000 ft MSL; Aircraft X switched to the OKB CTAF frequency and began a final descent into OKB tracking the VOR-A approach. At this time; Aircraft X also announced on the OKB CTAF that it was inbound on the VOR-A approach. Aircraft X initiated the approach at 3000 ft MSL; 500 ft higher than the published altitude at the IAF (OCN) to remain clear of the traffic in the hold. For the approach; the sole manipulator of the controls was an instrument rated commercial pilot; the safety pilot was a commercial pilot and flight instructor acting as PIC.Aircraft X terminated the approach approximately 2 nm from OKB at an altitude of approximately 2000 ft MSL and airspeed of approximately 95 kts; at which point it began a gradual descending right turn to join the upwind leg for RWY 25 to sequence into the traffic pattern for landing due to other aircraft in the pattern on downwind. At this time; the safety pilot took over as sole manipulator of the controls to fly the final approach and landing.At 1600 ft MSL and while still in a gradual descending right turn to join the upwind leg for RWY 25; Aircraft X took immediate evasive action by initiating a steep left turn to avoid a midair collision with the Aircraft Y. Aircraft Y was overtaking Aircraft X in a climbing right turn after departing RWY 25 at OKB and crossed from left to right underneath Aircraft X. Until the time at which Aircraft X took evasive action; neither pilot in Aircraft X had visual contact with Aircraft Y; nor did the pilots of Aircraft X hear any radio calls from Aircraft Y on the OKB CTAF. Aircraft Y took no evasive action to prevent a midair collision. The estimated miss distance was less than 200 ft vertically and less than 300 ft horizontally. The incident occurred approximately 1.5 NM west of the departure end of RWY 25 at OKB. The location of the incident does not coincide with the standard traffic pattern for departures from OKB; and Aircraft Y did not report it was initiating a crosswind turn to the right from runway heading. After the incident; Aircraft X proceeded to land uneventfully at OKB.




Synopsis: Pilot reported a NMAC while in the landing phase of flight.