Narrative:

We pushed back from gate in sacramento. Once ready to taxi, we were given taxi instructions to runway 16R via taxiway a and were asked to report established on taxiway a. Both the captain and I had our smf airport diagrams out and were referring to them. Following the taxi line, we exited the ramp at taxiway A9 and turned right on the taxi line. I reported established on taxiway a. Moments later, the captain spotted hold short lines and stopped the jet. It took us both by surprise. We both felt certain that we had turned on to taxiway a. However, we had not. We then realized that we were on taxiway A9. I told ground control that we were not on taxiway a, but were inadvertently on taxiway A9 holding short. Ground asked us if we could do a 180 degree turn to get back to taxiway a. We were unable. The captain asked the ground controller if we could enter the runway at taxiway A9, back-taxi to runway 16R, and exit at taxiway A8 to rejoin taxiway a. Ground control had us contact tower and then the tower controller cleared us to taxi onto the runway and exit at taxiway A8. We returned to ground frequency and were given permission to continue our taxi to runway 16R. We taxied to runway 16R for a normal takeoff. On the airport diagram it states, 'be alert for closely aligned taxiway ctrlines' and it includes an enlarged pictorial of the intersection at taxiway A9. Even with this information in front of us, we thought that we were on taxiway a when in reality we were on taxiway A9 heading toward the runway. It's still hard to believe that we made the wrong turn! In retrospect, I have 2 recommendations that could help this from happening to another crew. First, perhaps someone could physically paint the taxiway idents on the appropriate taxiway ctrlines (on the ground), so that there would be no question as to which line is which. Second, if the first recommendation is not feasible, during lower visibility aircraft should avoid using the intersection A9 between the ramp and taxiway a and be routed another way. Callback conversation with reporter revealed the following information: reporter stated the tower reported visibility at the time was 1/4 mi with the sun just rising. This combination of light diffusion in the fog with the low sun angle and not full sunlight yet caused the crew to miss the taxiway signs. The reporter and the captain discussed the potential taxiway confusion prior to leaving the gate area and yet taxied onto the incorrect taxiway anyway. The reporter stated the signs basically state 'you are already here,' not 'go there.' a better presentation might be taxiway designations painted on the taxiway.

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Original NASA ASRS Text

Title: AN MD80 CREW IN A LOW VISIBILITY TAXI AT SMF MISSED TXWY A AND TAXIED ONTO TXWY A9 AND STOPPED SHORT OF RWY 16R.

Narrative: WE PUSHED BACK FROM GATE IN SACRAMENTO. ONCE READY TO TAXI, WE WERE GIVEN TAXI INSTRUCTIONS TO RWY 16R VIA TXWY A AND WERE ASKED TO RPT ESTABLISHED ON TXWY A. BOTH THE CAPT AND I HAD OUR SMF ARPT DIAGRAMS OUT AND WERE REFERRING TO THEM. FOLLOWING THE TAXI LINE, WE EXITED THE RAMP AT TXWY A9 AND TURNED R ON THE TAXI LINE. I RPTED ESTABLISHED ON TXWY A. MOMENTS LATER, THE CAPT SPOTTED HOLD SHORT LINES AND STOPPED THE JET. IT TOOK US BOTH BY SURPRISE. WE BOTH FELT CERTAIN THAT WE HAD TURNED ON TO TXWY A. HOWEVER, WE HAD NOT. WE THEN REALIZED THAT WE WERE ON TXWY A9. I TOLD GND CTL THAT WE WERE NOT ON TXWY A, BUT WERE INADVERTENTLY ON TXWY A9 HOLDING SHORT. GND ASKED US IF WE COULD DO A 180 DEG TURN TO GET BACK TO TXWY A. WE WERE UNABLE. THE CAPT ASKED THE GND CTLR IF WE COULD ENTER THE RWY AT TXWY A9, BACK-TAXI TO RWY 16R, AND EXIT AT TXWY A8 TO REJOIN TXWY A. GND CTL HAD US CONTACT TWR AND THEN THE TWR CTLR CLRED US TO TAXI ONTO THE RWY AND EXIT AT TXWY A8. WE RETURNED TO GND FREQ AND WERE GIVEN PERMISSION TO CONTINUE OUR TAXI TO RWY 16R. WE TAXIED TO RWY 16R FOR A NORMAL TKOF. ON THE ARPT DIAGRAM IT STATES, 'BE ALERT FOR CLOSELY ALIGNED TXWY CTRLINES' AND IT INCLUDES AN ENLARGED PICTORIAL OF THE INTXN AT TXWY A9. EVEN WITH THIS INFO IN FRONT OF US, WE THOUGHT THAT WE WERE ON TXWY A WHEN IN REALITY WE WERE ON TXWY A9 HEADING TOWARD THE RWY. IT'S STILL HARD TO BELIEVE THAT WE MADE THE WRONG TURN! IN RETROSPECT, I HAVE 2 RECOMMENDATIONS THAT COULD HELP THIS FROM HAPPENING TO ANOTHER CREW. FIRST, PERHAPS SOMEONE COULD PHYSICALLY PAINT THE TXWY IDENTS ON THE APPROPRIATE TXWY CTRLINES (ON THE GND), SO THAT THERE WOULD BE NO QUESTION AS TO WHICH LINE IS WHICH. SECOND, IF THE FIRST RECOMMENDATION IS NOT FEASIBLE, DURING LOWER VISIBILITY ACFT SHOULD AVOID USING THE INTXN A9 BTWN THE RAMP AND TXWY A AND BE ROUTED ANOTHER WAY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE TWR RPTED VISIBILITY AT THE TIME WAS 1/4 MI WITH THE SUN JUST RISING. THIS COMBINATION OF LIGHT DIFFUSION IN THE FOG WITH THE LOW SUN ANGLE AND NOT FULL SUNLIGHT YET CAUSED THE CREW TO MISS THE TXWY SIGNS. THE RPTR AND THE CAPT DISCUSSED THE POTENTIAL TXWY CONFUSION PRIOR TO LEAVING THE GATE AREA AND YET TAXIED ONTO THE INCORRECT TXWY ANYWAY. THE RPTR STATED THE SIGNS BASICALLY STATE 'YOU ARE ALREADY HERE,' NOT 'GO THERE.' A BETTER PRESENTATION MIGHT BE TXWY DESIGNATIONS PAINTED ON THE TXWY.

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.