Narrative:

After engine start, I received ATIS and contacted livermore ground for taxi clearance with ATIS, requesting right crosswind departure. I was authority/authorized to taxi to runway 7R, and read back my taxi clearance. I was aware that this clearance would require me to cross runway 7L, which I was also aware was active. During taxi, I thought it curious that I would be directed to runway 7R, but figured it was to allow the right crosswind departure request. I recall thinking during taxi that my clearance allows me to taxi to the assigned runway, crossing other runways, but does not allow me to taxi onto my assigned runway. During taxi, there was continuous radio traffic between ground controller and aircraft requesting radio check. The controller reported his xmissions as unreadable, yet I and another aircraft on frequency could read loud and clear. The other receiving aircraft reported this condition to ground. Upon arriving at runway 7L, I checked for traffic and noted an aircraft in position (holding) on runway 7L. Engine was idling, and it was clear that it did not pose a hazard. I proceeded across the hold line (for runway 7L) and reported to ground that I was proceeding across runway 7L. Ground asked me to say again, and I repeated my transmission. I was exiting the right edge of runway 7L when ground informed me not to cross, that I had been cleared to runway 7L, not runway 7R. I was directed to hold position between runways, and contact tower. After run-up, I was cleared to depart from runway 7R with a right crosswind departure. Human performance considerations: there is no way for me to be certain at this time if my clearance was to taxi to runway 7L or runway 7R. I can further not be certain if my readback was correct. I do know that I was surprised by the clearance, and was not hearing what I assumed or expected to be my clearance. From the time I received taxi instructions, I was under the impression that I was to taxi to the 'far' runway. As a low time pilot, and being aware of runway incursion as a significant safety concern, I decided to confirm with ground before proceeding across runway 7L. I cleared should have held behind the hold line until receiving positive confirmation, given my surprise at what I believe was my clearance. Had the aircraft in position on runway 7L not been clearly holding, I would not have proceeded. The approach end of runway 7L is about 300 yards displaced from the approach end of runway 7R. Runway 7R is considerably shorter than runway 7L. Audio clarity of received xmissions was not a factor.

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Original NASA ASRS Text

Title: A 'HOME BUILT' PLT, TAXIING FOR TKOF AT LVK, TAXIED ONTO AN ACTIVE RWY.

Narrative: AFTER ENG START, I RECEIVED ATIS AND CONTACTED LIVERMORE GND FOR TAXI CLRNC WITH ATIS, REQUESTING R XWIND DEP. I WAS AUTH TO TAXI TO RWY 7R, AND READ BACK MY TAXI CLRNC. I WAS AWARE THAT THIS CLRNC WOULD REQUIRE ME TO CROSS RWY 7L, WHICH I WAS ALSO AWARE WAS ACTIVE. DURING TAXI, I THOUGHT IT CURIOUS THAT I WOULD BE DIRECTED TO RWY 7R, BUT FIGURED IT WAS TO ALLOW THE R XWIND DEP REQUEST. I RECALL THINKING DURING TAXI THAT MY CLRNC ALLOWS ME TO TAXI TO THE ASSIGNED RWY, XING OTHER RWYS, BUT DOES NOT ALLOW ME TO TAXI ONTO MY ASSIGNED RWY. DURING TAXI, THERE WAS CONTINUOUS RADIO TFC BTWN GND CTLR AND ACFT REQUESTING RADIO CHK. THE CTLR RPTED HIS XMISSIONS AS UNREADABLE, YET I AND ANOTHER ACFT ON FREQ COULD READ LOUD AND CLR. THE OTHER RECEIVING ACFT RPTED THIS CONDITION TO GND. UPON ARRIVING AT RWY 7L, I CHKED FOR TFC AND NOTED AN ACFT IN POS (HOLDING) ON RWY 7L. ENG WAS IDLING, AND IT WAS CLR THAT IT DID NOT POSE A HAZARD. I PROCEEDED ACROSS THE HOLD LINE (FOR RWY 7L) AND RPTED TO GND THAT I WAS PROCEEDING ACROSS RWY 7L. GND ASKED ME TO SAY AGAIN, AND I REPEATED MY XMISSION. I WAS EXITING THE R EDGE OF RWY 7L WHEN GND INFORMED ME NOT TO CROSS, THAT I HAD BEEN CLRED TO RWY 7L, NOT RWY 7R. I WAS DIRECTED TO HOLD POS BTWN RWYS, AND CONTACT TWR. AFTER RUN-UP, I WAS CLRED TO DEPART FROM RWY 7R WITH A R XWIND DEP. HUMAN PERFORMANCE CONSIDERATIONS: THERE IS NO WAY FOR ME TO BE CERTAIN AT THIS TIME IF MY CLRNC WAS TO TAXI TO RWY 7L OR RWY 7R. I CAN FURTHER NOT BE CERTAIN IF MY READBACK WAS CORRECT. I DO KNOW THAT I WAS SURPRISED BY THE CLRNC, AND WAS NOT HEARING WHAT I ASSUMED OR EXPECTED TO BE MY CLRNC. FROM THE TIME I RECEIVED TAXI INSTRUCTIONS, I WAS UNDER THE IMPRESSION THAT I WAS TO TAXI TO THE 'FAR' RWY. AS A LOW TIME PLT, AND BEING AWARE OF RWY INCURSION AS A SIGNIFICANT SAFETY CONCERN, I DECIDED TO CONFIRM WITH GND BEFORE PROCEEDING ACROSS RWY 7L. I CLRED SHOULD HAVE HELD BEHIND THE HOLD LINE UNTIL RECEIVING POSITIVE CONFIRMATION, GIVEN MY SURPRISE AT WHAT I BELIEVE WAS MY CLRNC. HAD THE ACFT IN POS ON RWY 7L NOT BEEN CLRLY HOLDING, I WOULD NOT HAVE PROCEEDED. THE APCH END OF RWY 7L IS ABOUT 300 YARDS DISPLACED FROM THE APCH END OF RWY 7R. RWY 7R IS CONSIDERABLY SHORTER THAN RWY 7L. AUDIO CLARITY OF RECEIVED XMISSIONS WAS NOT A FACTOR.

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.