Flight crew misinterp of the published hold line creates a potential for wy intrusion.

Attributes
ACN	123756
Time
Date	198909
Day	Wed
Local Time Of Day	1201 To 1800
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	general aviation : personal
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	ground : holding ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 90 flight time total : 6800 flight time type : 2000
ASRS Report	123756
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	incursion : runway non adherence : clearance non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Airport	other physical facility

Narrative:

We were instructed to taxi to runway 4R, but hold short of 4L. While taxiing, ground control thought we would cross 4L prematurely and ordered us to stop. We evidently crossed the hold short line for 4L, which is some distance from the 4L threshold. Actually, the hold short line is on the other side of the runway 9 threshold. Runways 9 and 4L intersect close to their ends. We assumed there was another hold short line on the taxiway between runway 9 and runway 4L thresholds, not just 1 for both. There was no traffic conflict, only a bad assumption on our part. We did not infringe on the runway.

Original NASA ASRS Text

Title: FLT CREW MISINTERP OF THE PUBLISHED HOLD LINE CREATES A POTENTIAL FOR WY INTRUSION.

Narrative: WE WERE INSTRUCTED TO TAXI TO RWY 4R, BUT HOLD SHORT OF 4L. WHILE TAXIING, GND CTL THOUGHT WE WOULD CROSS 4L PREMATURELY AND ORDERED US TO STOP. WE EVIDENTLY CROSSED THE HOLD SHORT LINE FOR 4L, WHICH IS SOME DISTANCE FROM THE 4L THRESHOLD. ACTUALLY, THE HOLD SHORT LINE IS ON THE OTHER SIDE OF THE RWY 9 THRESHOLD. RWYS 9 AND 4L INTERSECT CLOSE TO THEIR ENDS. WE ASSUMED THERE WAS ANOTHER HOLD SHORT LINE ON THE TXWY BTWN RWY 9 AND RWY 4L THRESHOLDS, NOT JUST 1 FOR BOTH. THERE WAS NO TFC CONFLICT, ONLY A BAD ASSUMPTION ON OUR PART. WE DID NOT INFRINGE ON THE RWY.

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.