Air carrier captain reports confusion using the parking guidance system at dfw.

Attributes
ACN	804560
Time
Date	200809
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	agl single value : 0
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi ground other : gate arrival
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	804560
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Airport Flight Crew Human Performance
Primary Problem	Airport
Situations
Airport	other physical facility

Narrative:

Taxiing into parking at gate; parking spot has 2 lead-in lines. Started to turn onto wrong lead-in line. Parking guidance system did nothing to prevent me from starting down the wrong line. And; in fact; after I was lined up on wrong line it gave instructions that indicated I was in the correct position and I followed the indicator towards the parking spot. About 1/2 way from the entry spot to the parking spot; I began to get the red arrow correcting my mistake. This time I ended up with my nosewheels on the correct parking spot for my type airplane but the body of the aircraft was displaced to one side. After deplaning I checked the safety zone. The wingtip on the short side was on or within the safety setback lines. This is another shortcoming in the design of the parking guidance system. Crews need to be warned that they are still entirely responsible for selecting the correct lead-in line; that the parking guidance system will not warn them of their error. The parking guidance system should be re-engineered to provide such a warning. It should be able to detect the error at the first foot of the lead-in line to the parking spot and if it can't send a warning message to the crew; it should cease operation.

Original NASA ASRS Text

Title: ACR CAPT REPORTS CONFUSION USING THE PARKING GUIDANCE SYSTEM AT DFW.

Narrative: TAXIING INTO PARKING AT GATE; PARKING SPOT HAS 2 LEAD-IN LINES. STARTED TO TURN ONTO WRONG LEAD-IN LINE. PARKING GUIDANCE SYS DID NOTHING TO PREVENT ME FROM STARTING DOWN THE WRONG LINE. AND; IN FACT; AFTER I WAS LINED UP ON WRONG LINE IT GAVE INSTRUCTIONS THAT INDICATED I WAS IN THE CORRECT POS AND I FOLLOWED THE INDICATOR TOWARDS THE PARKING SPOT. ABOUT 1/2 WAY FROM THE ENTRY SPOT TO THE PARKING SPOT; I BEGAN TO GET THE RED ARROW CORRECTING MY MISTAKE. THIS TIME I ENDED UP WITH MY NOSEWHEELS ON THE CORRECT PARKING SPOT FOR MY TYPE AIRPLANE BUT THE BODY OF THE ACFT WAS DISPLACED TO ONE SIDE. AFTER DEPLANING I CHKED THE SAFETY ZONE. THE WINGTIP ON THE SHORT SIDE WAS ON OR WITHIN THE SAFETY SETBACK LINES. THIS IS ANOTHER SHORTCOMING IN THE DESIGN OF THE PARKING GUIDANCE SYS. CREWS NEED TO BE WARNED THAT THEY ARE STILL ENTIRELY RESPONSIBLE FOR SELECTING THE CORRECT LEAD-IN LINE; THAT THE PARKING GUIDANCE SYS WILL NOT WARN THEM OF THEIR ERROR. THE PARKING GUIDANCE SYS SHOULD BE RE-ENGINEERED TO PROVIDE SUCH A WARNING. IT SHOULD BE ABLE TO DETECT THE ERROR AT THE FIRST FOOT OF THE LEAD-IN LINE TO THE PARKING SPOT AND IF IT CAN'T SEND A WARNING MESSAGE TO THE CREW; IT SHOULD CEASE OP.

Data retrieved from NASA's ASRS site as of May 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.