Air carrier crew mishears crossing clearance and crosses hold short line.

Attributes
ACN	452290
Time
Date	199910
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : bos.airport
State Reference	MA
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : bos.tower
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	landing : roll
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 6000 flight time type : 800
ASRS Report	452290
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : multi engine
Experience	flight time last 90 days : 150 flight time total : 3800 flight time type : 870
ASRS Report	452285
Events
Anomaly	incursion : runway non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had just landed on runway 4R at xyz. We were holding short of runway 4L waiting to be cleared across. We then heard other aircraft being cleared to cross runway 4L, but those aircraft were south of us. The first officer thought that we were in front of these aircraft on the taxiway, so he called the tower and asked if we were cleared to cross runway 4L. The frequency was busy, but we thought we heard the tower reply 'yes you are' and so the first officer read back 'cleared to cross runway 4L.' as our nose crossed the hold short line, the tower called us and told us to hold short. We stopped with our nose roughly 8 ft over the hold short line. Confusion on the frequency and confusion on the part of our crew led to the misunderstanding. Our readback and the quick reaction of the controller prevented this misunderstanding from becoming a very bad situation. Closer attention to the frequency and to the position of the other aircraft would have greatly helped our crew from making this mistake. Supplemental information from acn 452303: fix: back to basics xyz may get frequency saturated, but I still have to get whole clearance including call sign. Supplemental information from acn 452285: this miscom could have been prevented if I had waited for the proper clearance to cross runway 4L. I believe the nearly 12 hour duty day was a factor.

Original NASA ASRS Text

Title: ACR CREW MISHEARS XING CLRNC AND CROSSES HOLD SHORT LINE.

Narrative: WE HAD JUST LANDED ON RWY 4R AT XYZ. WE WERE HOLDING SHORT OF RWY 4L WAITING TO BE CLRED ACROSS. WE THEN HEARD OTHER ACFT BEING CLRED TO CROSS RWY 4L, BUT THOSE ACFT WERE S OF US. THE FO THOUGHT THAT WE WERE IN FRONT OF THESE ACFT ON THE TXWY, SO HE CALLED THE TWR AND ASKED IF WE WERE CLRED TO CROSS RWY 4L. THE FREQ WAS BUSY, BUT WE THOUGHT WE HEARD THE TWR REPLY 'YES YOU ARE' AND SO THE FO READ BACK 'CLRED TO CROSS RWY 4L.' AS OUR NOSE CROSSED THE HOLD SHORT LINE, THE TWR CALLED US AND TOLD US TO HOLD SHORT. WE STOPPED WITH OUR NOSE ROUGHLY 8 FT OVER THE HOLD SHORT LINE. CONFUSION ON THE FREQ AND CONFUSION ON THE PART OF OUR CREW LED TO THE MISUNDERSTANDING. OUR READBACK AND THE QUICK REACTION OF THE CTLR PREVENTED THIS MISUNDERSTANDING FROM BECOMING A VERY BAD SIT. CLOSER ATTN TO THE FREQ AND TO THE POS OF THE OTHER ACFT WOULD HAVE GREATLY HELPED OUR CREW FROM MAKING THIS MISTAKE. SUPPLEMENTAL INFO FROM ACN 452303: FIX: BACK TO BASICS XYZ MAY GET FREQ SATURATED, BUT I STILL HAVE TO GET WHOLE CLRNC INCLUDING CALL SIGN. SUPPLEMENTAL INFO FROM ACN 452285: THIS MISCOM COULD HAVE BEEN PREVENTED IF I HAD WAITED FOR THE PROPER CLRNC TO CROSS RWY 4L. I BELIEVE THE NEARLY 12 HR DUTY DAY WAS 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.