Narrative:

As we taxied into gate in lga the ground agent marshaled us in with wands. As we approached our parking stop, he brought his wands together and then held them crossed, over his head, indicating we should stop. I set parking brake and shut down engines. The ramp agent walked toward the jetway, took a wand in each hand, held them over his head and brought the tips together. (This is the generally accepted 'chocks are in signal.') I then released the brake and called for the parking checklist. Unknown to me, the aircraft had started rolling back, ground personnel banged on the side of the aircraft, and I brought the aircraft to a stop. The ramp agent denied having given me the 'chocks in' signal. After consideration I came to the conclusion that he either was signaling the other ground crew to chock the aircraft, or was so used to giving this signal after stopping the aircraft, that he did it without thinking. In any event, I went to our operations manual and found to my dismay that there is no official 'chocks are in' signal. We have all been operating under a norm which is not published and is nonstandard. We need to either incorporate this signal in our manuals or put out a letter telling our pilots not to release brakes until we receive the 'release brakes' signal.

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Original NASA ASRS Text

Title: ACR PIC RELEASES PARKING BRAKE AT GATE ON ARR WITHOUT CHOCKS. ACFT ROLLS BACK UNTIL GND CREW ALERTS CAPT.

Narrative: AS WE TAXIED INTO GATE IN LGA THE GND AGENT MARSHALED US IN WITH WANDS. AS WE APCHED OUR PARKING STOP, HE BROUGHT HIS WANDS TOGETHER AND THEN HELD THEM CROSSED, OVER HIS HEAD, INDICATING WE SHOULD STOP. I SET PARKING BRAKE AND SHUT DOWN ENGS. THE RAMP AGENT WALKED TOWARD THE JETWAY, TOOK A WAND IN EACH HAND, HELD THEM OVER HIS HEAD AND BROUGHT THE TIPS TOGETHER. (THIS IS THE GENERALLY ACCEPTED 'CHOCKS ARE IN SIGNAL.') I THEN RELEASED THE BRAKE AND CALLED FOR THE PARKING CHKLIST. UNKNOWN TO ME, THE ACFT HAD STARTED ROLLING BACK, GND PERSONNEL BANGED ON THE SIDE OF THE ACFT, AND I BROUGHT THE ACFT TO A STOP. THE RAMP AGENT DENIED HAVING GIVEN ME THE 'CHOCKS IN' SIGNAL. AFTER CONSIDERATION I CAME TO THE CONCLUSION THAT HE EITHER WAS SIGNALING THE OTHER GND CREW TO CHOCK THE ACFT, OR WAS SO USED TO GIVING THIS SIGNAL AFTER STOPPING THE ACFT, THAT HE DID IT WITHOUT THINKING. IN ANY EVENT, I WENT TO OUR OPS MANUAL AND FOUND TO MY DISMAY THAT THERE IS NO OFFICIAL 'CHOCKS ARE IN' SIGNAL. WE HAVE ALL BEEN OPERATING UNDER A NORM WHICH IS NOT PUBLISHED AND IS NONSTANDARD. WE NEED TO EITHER INCORPORATE THIS SIGNAL IN OUR MANUALS OR PUT OUT A LETTER TELLING OUR PLTS NOT TO RELEASE BRAKES UNTIL WE RECEIVE THE 'RELEASE BRAKES' SIGNAL.

Data retrieved from NASA's ASRS site as of July 2007 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.