Air carrier X taxiway excursion. Pilot deviation. Situation: poor taxiway marking signs.

Attributes
ACN	198534
Time
Date	199201
Day	Tue
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4700 flight time type : 2220
ASRS Report	198534
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Airport
Air Traffic Incident	Pilot Deviation other
Situations
Airport	other physical facility

Narrative:

Air carrier X upon leaving the gate at sfo we were assigned runway 10R for departure. Having never used this runway for takeoff, this section of the airport was unfamiliar, combined with the facts that it was a departure and it was raining. Taxiing along the inner taxiway a until south we approached the departure end of runway 10R. Due to the time and that there was no traffic, tower cleared us for takeoff prior to approaching the hold short. So while trying to look outside, in the rain, at night, at confusing taxi lights, and at the airport diagram, we taxied onto runway 10R and departed. No further incident occurred. Looking back and studying the airport diagram very carefully we had turned right off of taxiway right onto runway 10R and crossed a small section of pavement which was neither runway nor taxiway. At the time during the rain, darkness, confusing taxiway lights and runway identify signs, we appeared to have taxied correctly. Only upon an uncertain feeling and a second look, we figured out exactly what had happened. Nothing was damaged and we were lucky but next time if you are unsure, stop and ask.

Original NASA ASRS Text

Title: ACR X TAXIWAY EXCURSION. PLTDEV. SITUATION: POOR TAXIWAY MARKING SIGNS.

Narrative: ACR X UPON LEAVING THE GATE AT SFO WE WERE ASSIGNED RWY 10R FOR DEP. HAVING NEVER USED THIS RWY FOR TKOF, THIS SECTION OF THE ARPT WAS UNFAMILIAR, COMBINED WITH THE FACTS THAT IT WAS A DEP AND IT WAS RAINING. TAXIING ALONG THE INNER TAXIWAY A UNTIL S WE APCHED THE DEP END OF RWY 10R. DUE TO THE TIME AND THAT THERE WAS NO TFC, TWR CLRED US FOR TKOF PRIOR TO APCHING THE HOLD SHORT. SO WHILE TRYING TO LOOK OUTSIDE, IN THE RAIN, AT NIGHT, AT CONFUSING TAXI LIGHTS, AND AT THE ARPT DIAGRAM, WE TAXIED ONTO RWY 10R AND DEPARTED. NO FURTHER INCIDENT OCCURRED. LOOKING BACK AND STUDYING THE ARPT DIAGRAM VERY CAREFULLY WE HAD TURNED R OFF OF TAXIWAY R ONTO RWY 10R AND CROSSED A SMALL SECTION OF PAVEMENT WHICH WAS NEITHER RWY NOR TAXIWAY. AT THE TIME DURING THE RAIN, DARKNESS, CONFUSING TAXIWAY LIGHTS AND RWY IDENT SIGNS, WE APPEARED TO HAVE TAXIED CORRECTLY. ONLY UPON AN UNCERTAIN FEELING AND A SECOND LOOK, WE FIGURED OUT EXACTLY WHAT HAD HAPPENED. NOTHING WAS DAMAGED AND WE WERE LUCKY BUT NEXT TIME IF YOU ARE UNSURE, STOP AND ASK.

Data retrieved from NASA's ASRS site as of July 2007 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.