What was found
ON FLIGHT 3862, CREW REPORTED JUST AFTER TAKE OFF, AS THE LANDING GEAR RETRACTED, LAV SMOKE ALARM ON EICAS AND ALARM IN THE LAV SOUNDED. BOTH WENT AWAY WHEN LANDING GEAR WAS RETRACTED. ACFT REMOVED FROM SERVICE . PERFORMED OPS CHECK OF LAV SMOKE DETECTION SYS. IAW AMM 26-14-00 NO DEFECTS NOTED AT THIS TIME, NO OIL OR SMOKE SMELL DETECTED. ACFT RETURNED TO SERVICE.