DC8-71 crew had the controller confuse flts with similar call signs.

Attributes
ACN	566559
Time
Date	200211
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zid.artcc
State Reference	IN
Altitude	msl bound lower : 21000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	DC-8 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zid.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : private pilot : multi engine pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 11000 flight time type : 3500
ASRS Report	566559
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 150 flight time total : 6500 flight time type : 2000
ASRS Report	566730
Events
Anomaly	non adherence : published procedure
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : returned to assigned airspace
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

While we were at cruise at FL220, ZID on 128.07 called for us to descend to FL210. The first officer acknowledged and I descended the aircraft. As we approached leveloff, the controller called us again and asked us why we were descending. The first officer responded that 'that is what the controller had cleared us to do.' the controller answered that was meant for call sign Y, not call sign X, and for us to go back to FL220. So I did. Then about 1 min later, the controller called call sign Y and told him to descend to FL210! Obviously, call sign Y had not heard any clearance to descend. We could hear the controller make that call, but the call sign Y aircraft answered on a different frequency. It seemed that all other aircraft were on frequencys other than the one we were assigned. Later, as he was about to hand us off, the controller more or less apologized for the communications mix-up, mentioning similar call signs. Supplemental information from acn 566730: I am quite sure the controller cleared call sign X to maintain FL210 when he obviously meant to clear call sign Y. Unfortunately. The controller did not catch the mistake in clrncs after we read back the clearance we heard him give to us.

Original NASA ASRS Text

Title: DC8-71 CREW HAD THE CTLR CONFUSE FLTS WITH SIMILAR CALL SIGNS.

Narrative: WHILE WE WERE AT CRUISE AT FL220, ZID ON 128.07 CALLED FOR US TO DSND TO FL210. THE FO ACKNOWLEDGED AND I DSNDED THE ACFT. AS WE APCHED LEVELOFF, THE CTLR CALLED US AGAIN AND ASKED US WHY WE WERE DSNDING. THE FO RESPONDED THAT 'THAT IS WHAT THE CTLR HAD CLRED US TO DO.' THE CTLR ANSWERED THAT WAS MEANT FOR CALL SIGN Y, NOT CALL SIGN X, AND FOR US TO GO BACK TO FL220. SO I DID. THEN ABOUT 1 MIN LATER, THE CTLR CALLED CALL SIGN Y AND TOLD HIM TO DSND TO FL210! OBVIOUSLY, CALL SIGN Y HAD NOT HEARD ANY CLRNC TO DSND. WE COULD HEAR THE CTLR MAKE THAT CALL, BUT THE CALL SIGN Y ACFT ANSWERED ON A DIFFERENT FREQ. IT SEEMED THAT ALL OTHER ACFT WERE ON FREQS OTHER THAN THE ONE WE WERE ASSIGNED. LATER, AS HE WAS ABOUT TO HAND US OFF, THE CTLR MORE OR LESS APOLOGIZED FOR THE COMS MIX-UP, MENTIONING SIMILAR CALL SIGNS. SUPPLEMENTAL INFO FROM ACN 566730: I AM QUITE SURE THE CTLR CLRED CALL SIGN X TO MAINTAIN FL210 WHEN HE OBVIOUSLY MEANT TO CLR CALL SIGN Y. UNFORTUNATELY. THE CTLR DID NOT CATCH THE MISTAKE IN CLRNCS AFTER WE READ BACK THE CLRNC WE HEARD HIM GIVE TO US.

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.