Flight crew commences taxi without taxi clearance.

Attributes
ACN	314590
Time
Date	199508
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ewr
State Reference	NJ
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	A320
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9650 flight time type : 1550
ASRS Report	314590
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 12000 flight time type : 1700
ASRS Report	314706
Events
Anomaly	non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The ground controller was fairly busy. We called to taxi from ramp exit rc. We heard the ground controller say 'taxi outer, romeo for 22R, hold short of K.' I read back the clearance with our call sign and we started to taxi. Approaching G on the outer, the ground controller said he had not given us clearance. I told him that I had read the clearance back to him earlier. He told us that had been for another air carrier flight. Extreme radio congestion with a lot of transmissions being stepped on resulted in this misunderstanding.

Original NASA ASRS Text

Title: FLC COMMENCES TAXI WITHOUT TAXI CLRNC.

Narrative: THE GND CTLR WAS FAIRLY BUSY. WE CALLED TO TAXI FROM RAMP EXIT RC. WE HEARD THE GND CTLR SAY 'TAXI OUTER, ROMEO FOR 22R, HOLD SHORT OF K.' I READ BACK THE CLRNC WITH OUR CALL SIGN AND WE STARTED TO TAXI. APCHING G ON THE OUTER, THE GND CTLR SAID HE HAD NOT GIVEN US CLRNC. I TOLD HIM THAT I HAD READ THE CLRNC BACK TO HIM EARLIER. HE TOLD US THAT HAD BEEN FOR ANOTHER ACR FLT. EXTREME RADIO CONGESTION WITH A LOT OF TRANSMISSIONS BEING STEPPED ON RESULTED IN THIS MISUNDERSTANDING.

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.