A flight crew departed assigned altitude after accepting a clearance intended for another aircraft.

Attributes
ACN	438077
Time
Date	199905
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : hmv.vortac
State Reference	IN
Altitude	msl bound lower : 31700 msl bound upper : 33000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	cruise : level
Route In Use	enroute other
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise : level
Route In Use	enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 18000 flight time type : 20000
ASRS Report	438077
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 13000 flight time type : 11000
ASRS Report	439076
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to assigned airspace
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Requested ride reports as XXX #1. On reports of smoother rides, we requested FL250. ZID cleared us to FL250 and I acknowledged as XXX #1. The captain later said he thought he heard XXX #2, but since we had not heard an XXX #2 on frequency, thought the controller had made a mistake. Through FL317 the controller asked our altitude and then told us to climb immediately back to FL330. He then apologized twice for mixing up our call signs. As the trip has progressed we have been called YYY, ZZZ, and AAA, along with a variety of wrong flight numbers. When you query the controller, if you can get a word in at all, they become a bit testy. Supplemental information from acn 438076: we were told to expedite back to FL330 and another aircraft YYY was told to descend immediately to FL280(?). The center controller then apologized for the mix-up in call signs.

Original NASA ASRS Text

Title: A FLC DEPARTED ASSIGNED ALT AFTER ACCEPTING A CLRNC INTENDED FOR ANOTHER ACFT.

Narrative: REQUESTED RIDE RPTS AS XXX #1. ON RPTS OF SMOOTHER RIDES, WE REQUESTED FL250. ZID CLRED US TO FL250 AND I ACKNOWLEDGED AS XXX #1. THE CAPT LATER SAID HE THOUGHT HE HEARD XXX #2, BUT SINCE WE HAD NOT HEARD AN XXX #2 ON FREQ, THOUGHT THE CTLR HAD MADE A MISTAKE. THROUGH FL317 THE CTLR ASKED OUR ALT AND THEN TOLD US TO CLB IMMEDIATELY BACK TO FL330. HE THEN APOLOGIZED TWICE FOR MIXING UP OUR CALL SIGNS. AS THE TRIP HAS PROGRESSED WE HAVE BEEN CALLED YYY, ZZZ, AND AAA, ALONG WITH A VARIETY OF WRONG FLT NUMBERS. WHEN YOU QUERY THE CTLR, IF YOU CAN GET A WORD IN AT ALL, THEY BECOME A BIT TESTY. SUPPLEMENTAL INFO FROM ACN 438076: WE WERE TOLD TO EXPEDITE BACK TO FL330 AND ANOTHER ACFT YYY WAS TOLD TO DSND IMMEDIATELY TO FL280(?). THE CTR CTLR THEN APOLOGIZED FOR THE MIX-UP IN CALL SIGNS.

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.