AN ARRIVING AND A DEP ACR COME IN CLOSE PROX NEAR THE ARPT RESULTING IN AN NMAC.

Narrative

WE WERE APCHING ON J41 FROM PIE TO TLH. WX AT TLH WAS VFR WITH A CEILING AT 2500-3000 FT. THE CTLR CLRED US TO DSND TO 2000 FT MSL. SHORTLY THEREAFTER WE NOTICED AN ACR MLG Y DEPART ON RWY 9 AND CHK IN WITH THE CTLR. NEITHER OF US KNEW WHAT ALT HE WAS GOING TO BUT TYPICALLY DEPS AT TLH ARE CLRED TO 10000 FT MSL. WE BOTH ASSUMED THE MLG WOULD KEEP CLBING (THE CTLR TOLD US AFTERWARD BY TELEPHONE THAT THE MLG WAS ASSIGNED TO 2000 FT). AIRSPD: 200 KTS. THE CTLR POINTED OUT THE ARPT; WE CALLED IT IN SIGHT AND ALSO SAID THAT THE MLG WAS IN SIGHT. THE CTLR CLRED US FOR A VISUAL APCH TO RWY 18 AT TLH. WE HAD JUST REACHED 2000 FT AND WERE LEVEL. WE WERE ABEAM THE DEP END OF RWY 9 ABOUT 3-4 MI OUT. THE MLG WAS PROBABLY JUST CLBING OUT OF 1000 FT AND CALLED US IN SIGHT. AT SOME POINT WITHIN THE PREVIOUS FEW MOMENTS THE MLG WAS GIVEN A L TURN TO 340 DEGS. KEEP IN MIND THAT WE ASSUMED THE MLG WOULD KEEP CLBING. THE EFFECT OF THE TURN WAS TO PUT HIM ON A COLLISION COURSE WITH US. HE WOULD HAVE PASSED BEHIND US HAD HE HELD RWY HDG. WE HAD STOPPED OUR DSCNT AT 2000 FT AND WOULD HAVE DSNDED FURTHER FOR A PATTERN ALT BUT WE HAD ONLY JUST BEEN CLRED FOR THE VISUAL APCH. AT THIS POINT WE SAW THE MLG START THE TURN AND WE BECAME AWARE OF THE COLLISION POTENTIAL. THE CAPT WAS FLYING AND INITIATED A R TURN AWAY FROM THE OTHER ACFT. THEN THE MLG STOPPED ITS CLB AT OUR ALT. WE (THE CAPT) THEN BANKED APPROX 60 DEGS AND DOVE AWAY. AFTER WE RECEIVED A GPWS WARNING FOR TERRAIN CLOSURE RATE WE ROLLED OUT OF THE BANK AND LEVELED OFF AT 1500 FT. THE MLG THEN PULLED UP.