Air carrier large transport unauthorized runway crossing at bos.

Attributes
ACN	122465
Time
Date	198909
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : bos
State Reference	MA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	ground : holding ground other : taxi
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 14000 flight time type : 7000
ASRS Report	122465
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 7000
ASRS Report	122451
Events
Anomaly	conflict : ground less severe incursion : runway non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Airport	other physical facility

Narrative:

Left the gate with a taxi clearance to runway 9 outer taxiway bravo, S1 hold short runway 9 overrun. At south taxiway we held behind an air carrier Y when the line of aircraft in front started to move onto B. We were then cleared to follow the air carrier Y hold short of the 4L overrun. This was lead back. As we taxied around B taxiway we saw the 9 hold short line and the 9 overrun markings. I taxied around this looking for the 4L hold short line or the 4L overrun. At this time an air carrier Z large transport was on approach to what I thought was 4R. Seconds later it appeared he was headed right for us. Thinking I had crossed onto 4L, I immediately added power to get to S1 where I knew the aircraft would be safe.

Original NASA ASRS Text

Title: ACR LGT UNAUTH RWY CROSSING AT BOS.

Narrative: LEFT THE GATE WITH A TAXI CLRNC TO RWY 9 OUTER TXWY BRAVO, S1 HOLD SHORT RWY 9 OVERRUN. AT S TXWY WE HELD BEHIND AN ACR Y WHEN THE LINE OF ACFT IN FRONT STARTED TO MOVE ONTO B. WE WERE THEN CLRED TO FOLLOW THE ACR Y HOLD SHORT OF THE 4L OVERRUN. THIS WAS LEAD BACK. AS WE TAXIED AROUND B TXWY WE SAW THE 9 HOLD SHORT LINE AND THE 9 OVERRUN MARKINGS. I TAXIED AROUND THIS LOOKING FOR THE 4L HOLD SHORT LINE OR THE 4L OVERRUN. AT THIS TIME AN ACR Z LGT WAS ON APCH TO WHAT I THOUGHT WAS 4R. SECS LATER IT APPEARED HE WAS HEADED RIGHT FOR US. THINKING I HAD CROSSED ONTO 4L, I IMMEDIATELY ADDED PWR TO GET TO S1 WHERE I KNEW THE ACFT WOULD BE SAFE.

Data retrieved from NASA's ASRS site as of August 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.