Narrative:

I was PF and made what seemed to be a moderately hard landing (though I would not have expected it to cause any damage). I was endeavoring to down on the 1000 ft aim point and apparently flared late. Immediately on main wheel touchdown; the autothrottles advanced to a high power setting. I had perhaps 1 or 2 seconds to evaluate the situation and to make the decision to go around and that stopping on runway was not a safe alternative. After we were airborne; the autothrottles behaved erratically and as I was unsure as to the cause; I elected to declare an emergency and return to land on runway Y (the longer runway). Subsequently; I disconnected the autothrottles and land on runway Y without further difficulty.

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Original NASA ASRS Text

Title: B717 PLT EXECUTES A GAR AND DECLARES AN EMER AFTER A HARD LNDG; UNCOMMANDED AUTOTHROTTLE ADVANCE AND INADEQUATE STOPPING DISTANCE AVAILABLE.

Narrative: I WAS PF AND MADE WHAT SEEMED TO BE A MODERATELY HARD LNDG (THOUGH I WOULD NOT HAVE EXPECTED IT TO CAUSE ANY DAMAGE). I WAS ENDEAVORING TO DOWN ON THE 1000 FT AIM POINT AND APPARENTLY FLARED LATE. IMMEDIATELY ON MAIN WHEEL TOUCHDOWN; THE AUTOTHROTTLES ADVANCED TO A HIGH PWR SETTING. I HAD PERHAPS 1 OR 2 SECONDS TO EVALUATE THE SITUATION AND TO MAKE THE DECISION TO GO AROUND AND THAT STOPPING ON RWY WAS NOT A SAFE ALTERNATIVE. AFTER WE WERE AIRBORNE; THE AUTOTHROTTLES BEHAVED ERRATICALLY AND AS I WAS UNSURE AS TO THE CAUSE; I ELECTED TO DECLARE AN EMER AND RETURN TO LAND ON RWY Y (THE LONGER RWY). SUBSEQUENTLY; I DISCONNECTED THE AUTOTHROTTLES AND LAND ON RWY Y WITHOUT FURTHER DIFFICULTY.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.