Flight crew was taxiing to runway 31C at mdw; and crossed the hold line for 31L.

Attributes
ACN	779827
Time
Date	200803
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mdw.airport
State Reference	IL
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Light Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 91
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 85 flight time total : 12000 flight time type : 3000
ASRS Report	779827
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 50 flight time total : 15000 flight time type : 10
ASRS Report	779826
Events
Anomaly	incursion : runway non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Airport Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Our initial taxi clearance from south ramp was via taxiway Y; taxiway K; taxiway F; hold short runway 31L. We were unable to exit the ramp to taxiway Y but F2 was clear and requested to taxi via F2; which ground; after seeing our location; said that would be ok. Taxiing out; the first officer had the chart on his side and I had a garmin safe taxi diagram displayed. Approaching taxiway P; off to my left; I could see a runway 31L hold line for taxiway P; while in front of me a holding position sign for ILS critical area and a runway hold position sign; which must have been the runway 31L (what I must have thought was runway 31C). Visually; I was looking at 2 parallel runways (31C; 31R) while continuing to taxi slow; I was looking for the runway 31L hold when I realized that I had just crossed the line. Ground called and advised that I had taxied past the hold line. Ground asked us to continue to taxi behind the aircraft holding for runway 31C on taxiway F. A contributing factor was I let the first officer switch and get the latest ATIS at a critical time. Additionally; I never actually crossed the runway but rather encroached the safety approach area. I also don't remember seeing a modified taxiway centerline for runway 31L; if it was there I don't recall it. I must have confused the runway 31L/ILS as runway 31C; even though ILS signs do not have the runway it is associated with displayed. With both the ILS critical area hold sign (for runway 31C) and the runway 31L signs together was a contributing factor. The signs must look something like: '31L ILS.' a clearance to taxi to hold short of the runway 31L approach; would have been helpful; as this would be alerting the pilot that they would never cross the runway. After arriving at my destination; I called back to the tower and discussed the matter briefly and was told that they have a lot of problems in that area. Having a sign '31L approach' and '31C ILS;' would have helped me and others in this situation. Renaming the runway 31L sign to runway 31L approach would have also helped.

Original NASA ASRS Text

Title: FLT CREW WAS TAXIING TO RWY 31C AT MDW; AND CROSSED THE HOLD LINE FOR 31L.

Narrative: OUR INITIAL TAXI CLRNC FROM SOUTH RAMP WAS VIA TXWY Y; TXWY K; TXWY F; HOLD SHORT RWY 31L. WE WERE UNABLE TO EXIT THE RAMP TO TXWY Y BUT F2 WAS CLR AND REQUESTED TO TAXI VIA F2; WHICH GND; AFTER SEEING OUR LOCATION; SAID THAT WOULD BE OK. TAXIING OUT; THE FO HAD THE CHART ON HIS SIDE AND I HAD A GARMIN SAFE TAXI DIAGRAM DISPLAYED. APCHING TXWY P; OFF TO MY L; I COULD SEE A RWY 31L HOLD LINE FOR TXWY P; WHILE IN FRONT OF ME A HOLDING POS SIGN FOR ILS CRITICAL AREA AND A RWY HOLD POS SIGN; WHICH MUST HAVE BEEN THE RWY 31L (WHAT I MUST HAVE THOUGHT WAS RWY 31C). VISUALLY; I WAS LOOKING AT 2 PARALLEL RWYS (31C; 31R) WHILE CONTINUING TO TAXI SLOW; I WAS LOOKING FOR THE RWY 31L HOLD WHEN I REALIZED THAT I HAD JUST CROSSED THE LINE. GND CALLED AND ADVISED THAT I HAD TAXIED PAST THE HOLD LINE. GND ASKED US TO CONTINUE TO TAXI BEHIND THE ACFT HOLDING FOR RWY 31C ON TXWY F. A CONTRIBUTING FACTOR WAS I LET THE FO SWITCH AND GET THE LATEST ATIS AT A CRITICAL TIME. ADDITIONALLY; I NEVER ACTUALLY CROSSED THE RWY BUT RATHER ENCROACHED THE SAFETY APCH AREA. I ALSO DON'T REMEMBER SEEING A MODIFIED TXWY CTRLINE FOR RWY 31L; IF IT WAS THERE I DON'T RECALL IT. I MUST HAVE CONFUSED THE RWY 31L/ILS AS RWY 31C; EVEN THOUGH ILS SIGNS DO NOT HAVE THE RWY IT IS ASSOCIATED WITH DISPLAYED. WITH BOTH THE ILS CRITICAL AREA HOLD SIGN (FOR RWY 31C) AND THE RWY 31L SIGNS TOGETHER WAS A CONTRIBUTING FACTOR. THE SIGNS MUST LOOK SOMETHING LIKE: '31L ILS.' A CLRNC TO TAXI TO HOLD SHORT OF THE RWY 31L APCH; WOULD HAVE BEEN HELPFUL; AS THIS WOULD BE ALERTING THE PLT THAT THEY WOULD NEVER CROSS THE RWY. AFTER ARRIVING AT MY DEST; I CALLED BACK TO THE TWR AND DISCUSSED THE MATTER BRIEFLY AND WAS TOLD THAT THEY HAVE A LOT OF PROBS IN THAT AREA. HAVING A SIGN '31L APCH' AND '31C ILS;' WOULD HAVE HELPED ME AND OTHERS IN THIS SITUATION. RENAMING THE RWY 31L SIGN TO RWY 31L APCH WOULD HAVE ALSO HELPED.

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.