Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 50; Flight Crew Total 1000; Flight Crew Type 300
Communication Breakdown; Confusion; Training / Qualification
Conflict Airborne Conflict
General None Reported / Taken
Airport; Human Factors
Our C150 training flight announced a 1/2 mile right base to final for SNL Runway 17. Another aircraft identified itself as 'flight check Challenger on 5 mile final.' The flight check aircraft then proceeded to announce 'this isn't going to work.' Our aircraft asked 'will you be going around then?' A comment was made to the effect of 'this will be the last one.' Flight check aircraft then proceeded to fly under our aircraft [between our C150 on final and the runway.] Upon seeing the aircraft appear underneath our flight while on final we asked 'flight check; did you see us as you flew under us on final?' Flight check responded 'yes; we saw you.' Our aircraft went around and landed uneventfully. The 'flight check Challenger' departed the area to the west. At no time did our C150 training flight do anything other than enter and fly the VFR traffic patter per the FAR/AIM and A/FD.
A breakdown in communication between a straight in Challenger and a base leg C150 at a non-towered airport resulted in a close encounter on final.