What was found
DURING DESCENT, ON ARRIVAL INTO PBI AROUND 24000 FT, GOT STAB TRIM & MACH TRIM ICAS ON PROCEEDED WITH CHKLIST & TRIED TO RE-ENGADED NO SUCCESS. AS WE WERE SLOWING DOWN, GETTING HEAVIER & HEAVIER NOSE DOWN, DECLARED EMERGENCY, AROUND 10000FT ON SHORT FINAL THE NOSE WAS SO HEAVY SO BOTH HAD TO HOLD THE YOKE BACK ALMOST NORMAL LANDING, TAXI TO FBO. REMOVED DEFECTIVE PILOT PITCH TRIM DISCONNECT SWITCH AND INSTALLED A CUSTOMER SUPPLIED NEW PITCH TRIM DISCONNECT SWITCH. REMOVED DEFECTIVE COPILOT PITCH TRIM DISCONNECT SWITCH AND INSTALLED A SUPPLIED NEW PITCH TRIM DISCONNECT SWITCH. PERFORMED OPS CHK & CHKD GOOD. NO DEFECTS NOTED IAW AMM 27-41-07.