Any Unknown or Unlisted Aircraft Manufacturer
Confusion; Communication Breakdown; Situational Awareness
Conflict Airborne Conflict
Flight Crew Took Evasive Action
Human Factors
We set up to land on RWY 35 going into KTRM. As we entering the airport area and we realized that a Aircraft Y was landing on RWY 17. I quickly briefed we would over fly the airport and make right traffic for 17. Then my non flying pilot said they were making left traffic and we would have to make left traffic. (I prefer to make right traffic since I fly from the right seat and it is much easier to see the RWY) I brief I would fly a wide up wind; flying along a ridge line and at the end of the ridge line I would turn right and enter the pattern on a 45. As we were on the 45 more aircraft started to enter the pattern. Since the other aircraft in the pattern were not in sight I kept my downwind wide. My non flying pilot was calling my base turn since I could not see the RWY. Before we turned base an aircraft announced they were doing emergency procedures. [When we turned] base we got a TA (traffic advisory). Turned about 15 degrees to the right. The then the TA turned into a RA. I increased the power to take off power and pitch the nose up into the green as directed by the RA bars. My non flying pilot brought the gear up and went to emergency power. I did not feel it was necessary to go to emergency power; since we were climbing away from the traffic. The RA went away about 1800 to 2000 feet. We re-entered the traffic pattern and landed with no further problems. After we landed we realized it was a helicopter that was doing emergency procedures. My non flying pilot was very concerned at the length of the RA; that's why he pushed it up to emergency power. We both agree that there was a lot going on in the pattern with multiple aircraft and a helicopter doing emergency work. It was very bad judgment on the helicopter pilot to be doing emergency work (they must [have] been hovering) in the pattern of an uncontrolled airport with multiple jets in the pattern. I flew a wider downwind because we did not have the traffic in sight.
General Aviation pilot reported receiving an RA on the base leg at a non-towered airport requiring evasive action.