Medium Transport; Low Wing; 2 Turbojet Eng
Flight Attendant Current
Communication Breakdown; Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Ground Event / Encounter Other / Unknown
Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Company Policy; Human Factors; Procedure
After landing we taxied to the gate. We pulled into the ramp area which saw a 'wing walker' out the galley service window. The aircraft stopped with its usual 'brakes on' stop at the gate and the seat belt sign was turned off. I turned on the cabin lighting to bright; exited my jumpseat; and awaited flight deck signal to open the main cabin door (a single chime). A single chime was audible in the cabin and I looked at the FA (Flight Attendant) panel with no indication and opened the main cabin door. When the door popped open I noticed the sky moving as if the aircraft was moving and heard the flight deck receive the 'Door Door' notification. It was then that I could hear the engines were coming back up and I looked up to see the seat belt sign had been re-illuminated. The flight deck immediately opened the flight deck door and said to close the main cabin door. We finished pulling into the gate a few feet and open the main cabin door. The captain stated that he had turned the seat belt sign on. I explained that the open door chime and the seat belt sign chime were the same so I heard the chime looked at the panel and opened the door per the current procedure.  I believe the current 'single chime' communication from the flight deck for main cabin door opening is not effective communication. There are 76 seats which have a flight attendant call button which makes the same chime. The seat belt on/off makes the same exact chime. The lav call lights make the same exact chime. I believe we have an opportunity to make communication for opening the flight deck door more effective and less risky of being confused. I would suggest the using the same chime that is used at sterile which is a single chime that happens twice. At the door open this chime would be completely different from any calls from the flight deck/aft fa (high low chimes) or the passenger seats; lav call light; and seat belt sign on/off (a single chime). Using a single chime that tones twice as with the notification for Sterile would prevent mixed messages because it is only used to indicate sterile at this time.
After a CRJ-900 stopped at the gate; the Captain turned the seat belt sign off which produced a single chime. As per training; the forward Flight Attendant opened the forward cabin door after a second chime. After opening the door the aircraft began moving. The seat belt sign had been re-illuminated but identical sounding chimes for different commands in certain situations led to confusion and potentially safety consequences.