Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 183; Flight Crew Total 2371; Flight Crew Type 1511
Situational Awareness; Communication Breakdown
Conflict NMAC; Conflict Airborne Conflict
Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Human Factors
I was in Aircraft X following Aircraft Y along with Aircraft Z. All three aircraft were doing pattern work for at least 30 minutes prior to the incident. For the most part ATC was requiring full stop taxi backs.My plane; Aircraft X; was cleared to land number 2 after Aircraft Y; which was cleared to land number 1.I watched Aircraft Y turn a 1 mile base over the channel coming from the cement plant; which is the typical position for base to final for traffic at San Carlos; soon after receiving sequence and clearance to land. As Aircraft Y approached its turn to final; I saw Aircraft Z on an extended final on a direct collision course with Aircraft Y. Aircraft Y confirmed sequence #2 as opposed to #1 cleared to land and took evasive action.Aircraft Y performed evasive action; 45-60 degree bank turn climbing; and narrowly missed Aircraft Z. Aircraft Z did not change course or direction. ATC then amended the clearance for Aircraft Y to Number 2 for landing and amended my clearance for number 3 for landing. Both planes Aircraft Y and Z landed safely and parked. Somehow; ATC mixed up the sequence. I suspect most likely both Aircraft Y and Z were cleared to land and it was only that the pilot on Aircraft Y looked up the approach path and saw Aircraft Z; and took evasive action that a midair collision was averted.
Flight Instructor reported a near midair collision in the airport traffic pattern.