AUTOTHROTTLES ADVANCED ON TOUCHDOWN RESULTING IN AN LGT BOUNCING BACK INTO THE AIR MOMENTARILY. HOWEVER; IT DID COME BACK DOWN PRIOR TO THE FO PUTTING THE THROTTLES TO FLT IDLE.

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A VERY SHORT FLT (20 MINS) DELAYED 5 MINS TO DEFER AN INOP TCASII. AN FAA INSPECTOR ON JUMPSEAT. HIGH WORKLOAD ENVIRONMENT WITH NUMEROUS TA'S GIVEN BY ATC DUE TO OUTBOUND DEN TFC. FO MADE VISUAL HAND FLOWN APCH AND LNDG. ON TOUCHDOWN; THROTTLES ADVANCED AND SPD LEVER DISARMED; ACFT SKIPPED SLIGHTLY BUT TOUCHED DOWN AGAIN BEFORE FO BROUGHT THROTTLES TO IDLE AND THEN REVERSE; AT WHICH POINT THE SPD BRAKES AUTO DEPLOYED. THIS IS CONSISTENT WITH HAVING THE AUTOTHROTTLES ENGAGED AT TOUCHDOWN AND IS NOT A BIG DEAL PROB EXCEPT FOR THE UNEXPECTED SURPRISE; AND THIS DOES EAT UP SOME RWY WHILE A RECOVERY IS MADE TO NORMAL. THE FO BELIEVES HE DISENGAGED THE AUTOTHROTTLES AT THE SAME TIME AS THE AUTOPLT. HOWEVER; WE PROBABLY USED FLECHETTE DURING AN ENSUING ALT CHANGE WHICH WOULD HAVE REENGAGED THE AUTOTHROTTLES AT A TIME WHEN THROTTLES WERE AT IDLE; THUS NO SENSORY INPUT. THEREAFTER; AUTOTHROTTLE MOVEMENT MIGHT MATCH PLT INPUTS AND PLT WOULD NOT BE AWARE OF REENGAGEMENT. THIS IS; I THINK; ONE OF THE BAD ASPECTS OF THIS PARTICULAR AUTOFLT SYS. AUTOTHROTTLE ARM SWITCH HAS TO BE TURNED OFF TO PREVENT THIS FROM OCCURRING; BUT THEN WOULD NOT HAVE AUTOTHROTTLES IN CASE OF A MISSED APCH.