Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 20; Flight Crew Total 6000; Flight Crew Type 200
Situational Awareness; Communication Breakdown
Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action
Procedure; Airport; Company Policy; Environment - Non Weather Related; Human Factors
Aircraft X entered the left traffic pattern. Two [Small Transports] were in the pattern. Aircraft X announced downwind airspeed of 80 Knots. Twice during multiple approaches Aircraft Y initiated right traffic patterns. Aircraft X did announce 'Standard Pattern to Left;' with no response. Once Aircraft Z was on a right base almost at the same time Aircraft X was about to make a left base. AC-90-66B clearly states left hand traffic pattern is standard. This is the second time this conflict has happened. I understand [these aircraft] have a training requirement for right patterns. Training requirements do not trump FARs at non-government airports. A NASA ASR was submitted about a year ago for the same conflict. A nearby airport has two runways that require right traffic patterns. The event noted resulted in head-on situations resulting from non-standard pattern and standard left pattern operations.
Small aircraft pilot at a non towered airport reported two other aircraft were making non standard right traffic patterns and not communicating on the appropriate frequency.