E140 off stl climbs to FL260, but learns clearance was for company with similar call sign.

Attributes
ACN	564323
Time
Date	200210
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dsm.vortac
State Reference	IA
Altitude	msl bound lower : 25000 msl bound upper : 26000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc.artcc tower : cyhm.tower
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 140 ER&LR
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zkc.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 185 flight time total : 2400 flight time type : 800
ASRS Report	564323
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne critical inflight encounter : weather non adherence : clearance non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment other atc equipment : radar/mode c other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued advisory controller : issued new clearance flight crew : returned to assigned altitude other
Miss Distance	horizontal : 18000 vertical : 500
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Our crew departed st louis on the ozark 3 departure, mcm transition. After being handed off to ZKC, the controller cleared us to climb to FL250. Upon reaching FL250, several mi before mcm VOR, she then cleared us direct dsm VOR, and said to expect higher after passing traffic. Several mins later, approximately XA40 ct, while in IMC, the crew heard the controller clear us to climb to FL260. The captain read back '(our airline call sign and flight number), climbing to FL260.' (the controller did not return to the frequency with a correction. There was also a 'company' aircraft with a similar call sign behind us.) I entered FL260 in the altitude pre-select, the captain confirmed it, and I began the climb. The controller then came back to us, asking here we were going. The captain reminded her that she had cleared us to FL260. The controller said at that time that we were not cleared to FL260 and to return to FL250.

Original NASA ASRS Text

Title: E140 OFF STL CLBS TO FL260, BUT LEARNS CLRNC WAS FOR COMPANY WITH SIMILAR CALL SIGN.

Narrative: OUR CREW DEPARTED ST LOUIS ON THE OZARK 3 DEP, MCM TRANSITION. AFTER BEING HANDED OFF TO ZKC, THE CTLR CLRED US TO CLB TO FL250. UPON REACHING FL250, SEVERAL MI BEFORE MCM VOR, SHE THEN CLRED US DIRECT DSM VOR, AND SAID TO EXPECT HIGHER AFTER PASSING TFC. SEVERAL MINS LATER, APPROX XA40 CT, WHILE IN IMC, THE CREW HEARD THE CTLR CLR US TO CLB TO FL260. THE CAPT READ BACK '(OUR AIRLINE CALL SIGN AND FLT NUMBER), CLBING TO FL260.' (THE CTLR DID NOT RETURN TO THE FREQ WITH A CORRECTION. THERE WAS ALSO A 'COMPANY' ACFT WITH A SIMILAR CALL SIGN BEHIND US.) I ENTERED FL260 IN THE ALT PRE-SELECT, THE CAPT CONFIRMED IT, AND I BEGAN THE CLB. THE CTLR THEN CAME BACK TO US, ASKING HERE WE WERE GOING. THE CAPT REMINDED HER THAT SHE HAD CLRED US TO FL260. THE CTLR SAID AT THAT TIME THAT WE WERE NOT CLRED TO FL260 AND TO RETURN TO FL250.

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.