B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
No Specific Anomaly Occurred All Types
Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action
Human Factors
I am writing this report because of a safety concern; there were no mistakes or concerns with our flight just a light twin that was trying to fly the RNP Approach and could not complete it or follow ATC instructions.We were about to start the approach when we heard Approach Control trying to get the light twin to stay on assigned heading and climb. Over and over he had to tell him; you are turning the wrong way; you are not climbing. He cleared us for approach and I got a visual on him of my left wing; again ATC was trying to get him on heading and altitude. I was getting concerned about being close to the guy and asked ATC to keep us away from him; a short time after that we were told to make a right turn off the approach and climb to 4000'. He then told the guy; just fly straight. He asked him to go to a VFR field; land and get it together and try the approach later. The guy said no; he was then told he couldn't do the RNP again and tried the LOC next.We were back on the approach at that point and had an uneventful landing. I would like to add that the Approach Controller did a great job dealing with the other Pilot.My concern is having light twins flown by Pilots that shouldn't be flying IFR (due to lack of experience) being in the same place that we are flying. The result is that it makes for a tense and stressful situation. Again I am only writing this to point out a safety concern.
B737 Captain reported being vectored off the approach to avoid a light twin pilot that could not or would not comply with ATC instruction.