An MD80 crew, descending into ewr, responded to another aircraft's clearance.

Attributes
ACN	525502
Time
Date	200109
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ewr.airport
State Reference	NJ
Altitude	msl bound lower : 3000 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : n90.tracon
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : atp pilot : multi engine
Experience	flight time last 90 days : 170 flight time total : 11000 flight time type : 400
ASRS Report	525502
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : multi engine pilot : atp pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 6000 flight time type : 2500
ASRS Report	525871
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance controller : issued advisory
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Upon changeover from new york approach to the local newark approach controller, we apparently took someone else's altitude change. We checked in to newark approach level at 6000 ft. Our call sign was air carrier X. Immediately after I unkeyed the microphone after checking in, the approach controller responded 'air carrier X descend to 3000 ft.' we replied 'air carrier X, descending to 3000 ft.' the controller did not respond, and went on to other aircraft. The frequency was extremely busy as usual on newark approach. About 1.4 mins later, controller called us 'air carrier X, looks like you took someone else's clearance, no problem, remain at 3000 ft.' no separation problems occurred -- just radio confusion on a busy frequency. Supplemental information from acn 523871: changed radio frequency at 5000 ft MSL. Controller was busy and talking fast. When first officer reported in, I heard or thought I heard 'air carrier X descend to 3000 ft.' the first officer read back the new clearance 'air carrier X to 3000 ft.' leveling at 3000 ft, controller stated that we must have taken someone else's clearance.

Original NASA ASRS Text

Title: AN MD80 CREW, DSNDING INTO EWR, RESPONDED TO ANOTHER ACFT'S CLRNC.

Narrative: UPON CHANGEOVER FROM NEW YORK APCH TO THE LCL NEWARK APCH CTLR, WE APPARENTLY TOOK SOMEONE ELSE'S ALT CHANGE. WE CHKED IN TO NEWARK APCH LEVEL AT 6000 FT. OUR CALL SIGN WAS ACR X. IMMEDIATELY AFTER I UNKEYED THE MIKE AFTER CHKING IN, THE APCH CTLR RESPONDED 'ACR X DSND TO 3000 FT.' WE REPLIED 'ACR X, DSNDING TO 3000 FT.' THE CTLR DID NOT RESPOND, AND WENT ON TO OTHER ACFT. THE FREQ WAS EXTREMELY BUSY AS USUAL ON NEWARK APCH. ABOUT 1.4 MINS LATER, CTLR CALLED US 'ACR X, LOOKS LIKE YOU TOOK SOMEONE ELSE'S CLRNC, NO PROB, REMAIN AT 3000 FT.' NO SEPARATION PROBS OCCURRED -- JUST RADIO CONFUSION ON A BUSY FREQ. SUPPLEMENTAL INFO FROM ACN 523871: CHANGED RADIO FREQ AT 5000 FT MSL. CTLR WAS BUSY AND TALKING FAST. WHEN FO RPTED IN, I HEARD OR THOUGHT I HEARD 'ACR X DSND TO 3000 FT.' THE FO READ BACK THE NEW CLRNC 'ACR X TO 3000 FT.' LEVELING AT 3000 FT, CTLR STATED THAT WE MUST HAVE TAKEN SOMEONE ELSE'S CLRNC.

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.