A B767 crew, taxiing for takeoff at pdx, read back and responded to another aircraft's clearance.

Attributes
ACN	540783
Time
Date	200203
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : pdx.airport
State Reference	OR
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Weather Elements	Rain
Light	Night
Aircraft 1
Controlling Facilities	tower : mdw.tower
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	ground : position and hold
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 157 flight time total : 10000 flight time type : 800
ASRS Report	540783
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	incursion : runway non adherence : published procedure non adherence : clearance non adherence : far
Independent Detector	other controllera
Resolutory Action	controller : issued alert controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Holding short of runway 28L on taxiway east (parallel to runway). I heard '...position and hold, be ready for an immediate takeoff.' the captain said 'that was for us.' I transmitted to tower 'xxxxx cleared into position and hold, we'll be ready.' we taxied around the corner and onto the runway. The tower called us and said 'xxxxx, that was for another aircraft, you are now cleared into position and hold.' this was caused by 3 errors: 1) the captain heard our call sign in error. 2) the first officer (me) didn't verify the clearance with tower even though I hadn't heard the call sign. I did read back the clearance, but didn't confirm it. 3) apparently, the tower controller didn't hear our call sign when I read back the clearance and didn't realize the wrong aircraft responded until we took the runway. As the first officer on radio, I could have said 'verify xxxxx into position and hold' to signal the tower since I hadn't heard the call sign. But the captain had said it was for us and the tower didn't respond after my 'position and hold' call, so I assumed he was correct.

Original NASA ASRS Text

Title: A B767 CREW, TAXIING FOR TKOF AT PDX, READ BACK AND RESPONDED TO ANOTHER ACFT'S CLRNC.

Narrative: HOLDING SHORT OF RWY 28L ON TXWY E (PARALLEL TO RWY). I HEARD '...POS AND HOLD, BE READY FOR AN IMMEDIATE TKOF.' THE CAPT SAID 'THAT WAS FOR US.' I XMITTED TO TWR 'XXXXX CLRED INTO POS AND HOLD, WE'LL BE READY.' WE TAXIED AROUND THE CORNER AND ONTO THE RWY. THE TWR CALLED US AND SAID 'XXXXX, THAT WAS FOR ANOTHER ACFT, YOU ARE NOW CLRED INTO POS AND HOLD.' THIS WAS CAUSED BY 3 ERRORS: 1) THE CAPT HEARD OUR CALL SIGN IN ERROR. 2) THE FO (ME) DIDN'T VERIFY THE CLRNC WITH TWR EVEN THOUGH I HADN'T HEARD THE CALL SIGN. I DID READ BACK THE CLRNC, BUT DIDN'T CONFIRM IT. 3) APPARENTLY, THE TWR CTLR DIDN'T HEAR OUR CALL SIGN WHEN I READ BACK THE CLRNC AND DIDN'T REALIZE THE WRONG ACFT RESPONDED UNTIL WE TOOK THE RWY. AS THE FO ON RADIO, I COULD HAVE SAID 'VERIFY XXXXX INTO POS AND HOLD' TO SIGNAL THE TWR SINCE I HADN'T HEARD THE CALL SIGN. BUT THE CAPT HAD SAID IT WAS FOR US AND THE TWR DIDN'T RESPOND AFTER MY 'POS AND HOLD' CALL, SO I ASSUMED HE WAS CORRECT.

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.