A B737-300 captain using the self park system at phl taxied past the stop line when the system faile...

Attributes
ACN	728538
Time
Date	200702
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : phl.airport
State Reference	PA
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	728538
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : ground critical other anomaly other
Independent Detector	other other : 3
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Airport
Primary Problem	Airport

Narrative:

Undetected failure of the automated parking system on gate. Taxied in to gate at phl. Automated parking system showed 737 and to proceed. Parking system showed us on the taxi line and prompted us to continue. Parking system never showed us approaching the stop position or commanded us to stop. It just commanded that we continue. The ramp agent then banged on the side of the airplane and I stopped. I estimate that we had gone at least 10 feet beyond where we were supposed to stop and stopped within 4 or 5 feet of the jetway. If the ramp agent had not hit the side of the airplane I very well may have made contact with the jetway. I applied the brakes and stopped the airplane. I don't know what kind of self test this system has but it appears to have been inadequate today. I also don't if the ramp agents meeting the airplane to chock it are trained to be aware of this failure possibility. However the agent on the ground this time did an outstanding job and all agents need to be aware that this could happen.

Original NASA ASRS Text

Title: A B737-300 CAPT USING THE SELF PARK SYSTEM AT PHL TAXIED PAST THE STOP LINE WHEN THE SYSTEM FAILED TO DISPLAY A STOP MESSAGE. CAPT STOPPED WHEN THE GATE AGENT BANGED ON THE FUSELAGE.

Narrative: UNDETECTED FAILURE OF THE AUTOMATED PARKING SYSTEM ON GATE. TAXIED IN TO GATE AT PHL. AUTOMATED PARKING SYSTEM SHOWED 737 AND TO PROCEED. PARKING SYSTEM SHOWED US ON THE TAXI LINE AND PROMPTED US TO CONTINUE. PARKING SYSTEM NEVER SHOWED US APPROACHING THE STOP POSITION OR COMMANDED US TO STOP. IT JUST COMMANDED THAT WE CONTINUE. THE RAMP AGENT THEN BANGED ON THE SIDE OF THE AIRPLANE AND I STOPPED. I ESTIMATE THAT WE HAD GONE AT LEAST 10 FEET BEYOND WHERE WE WERE SUPPOSED TO STOP AND STOPPED WITHIN 4 OR 5 FEET OF THE JETWAY. IF THE RAMP AGENT HAD NOT HIT THE SIDE OF THE AIRPLANE I VERY WELL MAY HAVE MADE CONTACT WITH THE JETWAY. I APPLIED THE BRAKES AND STOPPED THE AIRPLANE. I DON'T KNOW WHAT KIND OF SELF TEST THIS SYSTEM HAS BUT IT APPEARS TO HAVE BEEN INADEQUATE TODAY. I ALSO DON'T IF THE RAMP AGENTS MEETING THE AIRPLANE TO CHOCK IT ARE TRAINED TO BE AWARE OF THIS FAILURE POSSIBILITY. HOWEVER THE AGENT ON THE GROUND THIS TIME DID AN OUTSTANDING JOB AND ALL AGENTS NEED TO BE AWARE THAT THIS COULD HAPPEN.

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.

A B737-300 captain using the self park system at phl taxied past the stop line when the system failed to display a stop message. Captain stopped when the gate agent banged on the fuselage.