What was found
DURING TAKEOFF, A LANDING GEAR AIR/GROUND FAIL MESSAGE SHORTLY AFTER TAKEOFF & LANDING GEAR LEVER WOULD NOT MOVE TO UP/LOCK POSITION. AIRCRAFT RETURNED AND LANDED UNEVENTFULLY. AIRCRAFT INSPECTED & LANDING GEAR DOWN AND PINNED. MX FERRIED TO BTV. T/S SYSTEM, REMOVED AND REPLACED LEFT MAIN LANDING GEAR NR 1 & 2 PROXIMITY SWITCHES IAW EMB AMM 32-63-01 P/N.80-057-01, S/N'S 3280 AND 3273 AND NOSE GEAR WOW PROXIMITY SWITCH IAW EMB145 AMM 32-63-02, OPS CHECKED SYSTEM GOOD. AIRCRAFT RETURNED TO SERVICE. NOTE: MAIN LANDING GEAR PROXIMITY SWITCHES P/N 80-057-01, S/N 3273 TSN/TSO 9392 HRS AND 7335 CYCLES//PROXIMITY SWITCH P/N 80-057-01, S/N 3280 TSN/TSO 7325 HRS AND 5897 CYCLES.