Taxi clearance misunderstanding. Aircraft taxied across active runway without clearance.

Attributes
ACN	325670
Time
Date	199601
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pit
State Reference	PA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
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 : 15000 flight time type : 6000
ASRS Report	325670
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 17000 flight time type : 11000
ASRS Report	325671
Events
Anomaly	incursion : runway non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While taxiing out of pit our ramp exit was very close to the taxiway and runway 28/10C. Ground issued a clearance to runway 28C via taxiway east with a clearance to cross runway 32. Due to a heavy workload in the cockpit and difficulty seeing the taxiway signs due to snow build-up, we misunderstood ground control's instructions as a clearance to cross runway 28C to runway 28L via taxiway east. I thought taxiway east was the parallel taxiway between runways 28C and 28L, and while I had my head down checking the airport diagram, the captain continued his taxi across runway 28C. After crossing the active runway, I saw an aircraft taxi into position and I realized our error at which point ground control questioned our actions. We were cleared to runway 28L without further incident. This was an avoidable human error and resulted from an excitable captain, dusk conditions, contaminated airport conditions, confusion as to our position and clearance and my own lack of forcefulness in being more assertive with this particular captain.

Original NASA ASRS Text

Title: TAXI CLRNC MISUNDERSTANDING. ACFT TAXIED ACROSS ACTIVE RWY WITHOUT CLRNC.

Narrative: WHILE TAXIING OUT OF PIT OUR RAMP EXIT WAS VERY CLOSE TO THE TXWY AND RWY 28/10C. GND ISSUED A CLRNC TO RWY 28C VIA TXWY E WITH A CLRNC TO CROSS RWY 32. DUE TO A HVY WORKLOAD IN THE COCKPIT AND DIFFICULTY SEEING THE TXWY SIGNS DUE TO SNOW BUILD-UP, WE MISUNDERSTOOD GND CTL'S INSTRUCTIONS AS A CLRNC TO CROSS RWY 28C TO RWY 28L VIA TXWY E. I THOUGHT TXWY E WAS THE PARALLEL TXWY BTWN RWYS 28C AND 28L, AND WHILE I HAD MY HEAD DOWN CHKING THE ARPT DIAGRAM, THE CAPT CONTINUED HIS TAXI ACROSS RWY 28C. AFTER XING THE ACTIVE RWY, I SAW AN ACFT TAXI INTO POS AND I REALIZED OUR ERROR AT WHICH POINT GND CTL QUESTIONED OUR ACTIONS. WE WERE CLRED TO RWY 28L WITHOUT FURTHER INCIDENT. THIS WAS AN AVOIDABLE HUMAN ERROR AND RESULTED FROM AN EXCITABLE CAPT, DUSK CONDITIONS, CONTAMINATED ARPT CONDITIONS, CONFUSION AS TO OUR POS AND CLRNC AND MY OWN LACK OF FORCEFULNESS IN BEING MORE ASSERTIVE WITH THIS PARTICULAR CAPT.

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.