B737 flight crew misunderstands taxi instructions from bhm ground controller who intended a runway 2...

Narrative:

Our taxi clearance from the gate was; 'cleared a; B intersection to runway 24.' I repeated the clearance and asked the captain if he thought they expected us to take off from B intersection. After looking at the chart; we saw that there was a jog in taxiway a where you had to get on B to continue on a to the end of runway 24. We both assumed that this was the intended clearance. As we made the jog on B; then turned on a again to proceed to the end (which crosses runway 36/18); tower came on and said; 'you're cleared to cross runway 36/18; I guess you missed B.' we had not passed the hold short line to runway 36/18; but were pretty close and still moving. We continued to runway 24 uneventfully. ATC never asked us if we could accept an intersection departure from B; and none of the taxiways or runways were notamed out; so we assumed we were going to use the full length by default.tower/ground should make sure they are clear on communicating their intentions; and we need to make sure we clarify if there are any questions about an odd clearance.

Original NASA ASRS Text

Title: B737 flight crew misunderstands taxi instructions from BHM Ground Controller who intended a Runway 24 departure from Taxiway B while the crew anticipated a full length departure.

Narrative: Our taxi clearance from the gate was; 'Cleared A; B Intersection to Runway 24.' I repeated the clearance and asked the Captain if he thought they expected us to take off from B Intersection. After looking at the chart; we saw that there was a jog in Taxiway A where you had to get on B to continue on A to the end of Runway 24. We both assumed that this was the intended clearance. As we made the jog on B; then turned on A again to proceed to the end (which crosses Runway 36/18); Tower came on and said; 'You're cleared to cross Runway 36/18; I guess you missed B.' We had not passed the hold short line to Runway 36/18; but were pretty close and still moving. We continued to Runway 24 uneventfully. ATC never asked us if we could accept an intersection departure from B; and none of the taxiways or runways were NOTAMed out; so we assumed we were going to use the full length by default.Tower/Ground should make sure they are clear on communicating their intentions; and we need to make sure we clarify if there are any questions about an odd clearance.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	866455
Time
Date	200912
Local Time Of Day	0601-1200
Place
Locale Reference	BHM.Airport
State Reference	AL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 295 Flight Crew Type 1550
Person 2
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 229 Flight Crew Type 7500
Events
Anomaly	ATC Issue All Types Ground Incursion Taxiway

B737 flight crew misunderstands taxi instructions from bhm ground controller who intended a runway 24 departure from taxiway B while the crew anticipated a full length departure.