This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
During a training flight to become familiarized and train towards a complex endorsement, my instructor and I were conducting circuits in the pattern at the airport.
The airport was unusually busy with four to five aircraft in the pattern and ATC was also handling various IFR clearances.
We were on our first downwind leg and ATC told us to extend our downwind a bit for traffic. We read back the instruction and continued on downwind.
At the point in the pattern where we usually turn base, ATC told us “Aircraft X you are now past traffic in opposite direction, make left traffic pattern at your discretion.”
I read back the instruction and me and my instructor took that to mean that we could start our left base turn.
We checked to visually make sure final was clear.
However, unknown to us there was another aircraft two miles to the north on a right base leg that started to turn final.
About 10 seconds after turning left my EFB gave me a traffic alert and I saw I was too close to the other incoming traffic. I did a steep left 180 to avoid coming into the other aircraft’s path.
Tower also notified us of the traffic alert and also asked us why we were not on downwind.
At that point my instructor took over the radios and told ATC the other aircraft was in sight and we were returning to our downwind leg.
After we landed we listened to the live ATC recording of our flight and came to the conclusion that ATC misspoke and that the call to “make left traffic pattern at your discretion” was meant for a different aircraft.
Primary Problem: Human Factors
ACN: 1840152
SITUATIONAL AWARENESS: I was on a right downwind for rwy 30 at Half Moon Bay (HAF) which is a right pattern when I noticed another aircraft at the same altitude and direction on a left downwind. I asked on CTAF for the intentions of the aircraft on the left downwind what his intentions were with no response. I then decided to extend my downwind to see what he was going to do and sure enough he turned left then final. I then turned right base then final and landed after him. As I was over the numbers there was an aircraft holding short yelling at me for making him wait to take off.
Scary way to learn about the communication challenges in the pattern – thankfully no one got hurt. The instruction to ‘make left traffic pattern’ wouldn’t be logical for an aircraft already assigned to left traffic and waiting for a clearance to turn base but when you hear your N#, it’s understandable that they proceeded to turn. A good lesson of another situation which can give you that uneasy feeling. Maybe time to verify with standardized terminology – ‘no traffic in sight, are we cleared to turn left base’.