A300
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Total 15000; Flight Crew Type 5000
Other / Unknown; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
General None Reported / Taken
Human Factors; Procedure
Aircraft movement after shutdown.  On arrival in ZZZ Ramp X at aircraft shutdown aircraft moved forward after a nose chock was inserted.  Both engines were shut down at the time of aircraft movement.  Movement was immediately after shutdown of Number 2 engine.  This was evident to me because the nose tiller turned 180 degrees right after Number 2 engine shutdown which at the time I assumed was some kind of mechanical malfunction.  After I was briefed by the mechanic [I] realized that it was caused by aircraft movement.  This baffled me because I didn't understand why.  When I got home I reread our shutdown procedures.  I noticed that I did not follow the cautions of checking the accumulator pressure being in the green band.  The truth be told I have not been checking this for years.  I have been checking for aircraft movement only after releasing the parking brake.  A huge mistake that thankfully did not cause any injuries or damage.  Most embarrassing for a seasoned Captain.  I guess I need to go through all my normal procedures again highlighting all cautions and warnings.  Surprising that in so many years of line checks and training events this bad habit never caught up with me.
A300 Captain reported the aircraft moved after engine shutdown with nose chock already inserted. No damage or injuries were reported.