B727 crew had altitude mixup with similar call sign air carrier.

Attributes
ACN	460102
Time
Date	200001
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : bae.vortac
State Reference	WI
Altitude	msl bound lower : 9600 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mke.tracon
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : mke.tracon
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 180 flight time total : 11000 flight time type : 1700
ASRS Report	460102
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 150 flight time total : 6000 flight time type : 800
ASRS Report	460370
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	ATC Human Performance FAA Flight Crew Human Performance
Primary Problem	ATC Human Performance
Situations
ATC Facility	procedure or policy : mke.tracon

Narrative:

Approach control issued us (air carrier abc) a descent from 10000 ft to 6000 ft. We read back and started descent. Different air carrier abc queried approach control as to similar call signs. Approach control acknowledged similar call signs. Overhearing this conversation, we (air carrier abc) stopped our descent at 9600 ft MSL and asked approach control to 'confirm our clearance to 6000 ft.' approach control responded 'that's ok, air carrier abc, 6000 ft will be fine.' at that point we were unsure if we had initially been cleared to 6000 ft or read back different air carrier abc's clearance. We would have been more alert if we had known of similar call signs. Airlines should be assigned non conflicting call signs. 'Air carrier abc' and 'different air carrier abc' sound similar over radios.

Original NASA ASRS Text

Title: B727 CREW HAD ALT MIXUP WITH SIMILAR CALL SIGN ACR.

Narrative: APCH CTL ISSUED US (ACR ABC) A DSCNT FROM 10000 FT TO 6000 FT. WE READ BACK AND STARTED DSCNT. DIFFERENT ACR ABC QUERIED APCH CTL AS TO SIMILAR CALL SIGNS. APCH CTL ACKNOWLEDGED SIMILAR CALL SIGNS. OVERHEARING THIS CONVERSATION, WE (ACR ABC) STOPPED OUR DSCNT AT 9600 FT MSL AND ASKED APCH CTL TO 'CONFIRM OUR CLRNC TO 6000 FT.' APCH CTL RESPONDED 'THAT'S OK, ACR ABC, 6000 FT WILL BE FINE.' AT THAT POINT WE WERE UNSURE IF WE HAD INITIALLY BEEN CLRED TO 6000 FT OR READ BACK DIFFERENT ACR ABC'S CLRNC. WE WOULD HAVE BEEN MORE ALERT IF WE HAD KNOWN OF SIMILAR CALL SIGNS. AIRLINES SHOULD BE ASSIGNED NON CONFLICTING CALL SIGNS. 'ACR ABC' AND 'DIFFERENT ACR ABC' SOUND SIMILAR OVER RADIOS.

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.