Flight crew was unintentionally descended.

Attributes
ACN	299303
Time
Date	199503
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gij
State Reference	MI
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : bdr
Operator	common carrier : air carrier
Make Model Name	Jetstream 31
Operating Under FAR Part	Part 135
Flight Phase	descent other
Route In Use	enroute airway : zau
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 3740 flight time type : 1500
ASRS Report	299303
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 270 flight time total : 500 flight time type : 300
ASRS Report	299411
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 intended course or assigned course other
Consequence	faa : reviewed incident with flight crew Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Commuter flight from lan to mdw. Approximately 45 NM from G1J on the 045 degree radial at 10000 ft. We were instructed by ZAU on 128.50 to descend and maintain 9000 ft. We acknowledged the call to descend and maintain 9000 ft and started down from 10000 ft. We responded, ' no, we were cleared to 9000 ft and on our way down. ZAU came back and replied that we were instructed to maintain 10000 ft. We replied that we understood we were cleared to 9000 ft. But would now go back to 10000 ft. We cleared back down to 9000 ft again. The flight proceeded without further incidents to mdw.

Original NASA ASRS Text

Title: FLC WAS UNINTENTIONALLY DSNDED.

Narrative: COMMUTER FLT FROM LAN TO MDW. APPROX 45 NM FROM G1J ON THE 045 DEG RADIAL AT 10000 FT. WE WERE INSTRUCTED BY ZAU ON 128.50 TO DSND AND MAINTAIN 9000 FT. WE ACKNOWLEDGED THE CALL TO DSND AND MAINTAIN 9000 FT AND STARTED DOWN FROM 10000 FT. WE RESPONDED, ' NO, WE WERE CLRED TO 9000 FT AND ON OUR WAY DOWN. ZAU CAME BACK AND REPLIED THAT WE WERE INSTRUCTED TO MAINTAIN 10000 FT. WE REPLIED THAT WE UNDERSTOOD WE WERE CLRED TO 9000 FT. BUT WOULD NOW GO BACK TO 10000 FT. WE CLRED BACK DOWN TO 9000 FT AGAIN. THE FLT PROCEEDED WITHOUT FURTHER INCIDENTS TO MDW.

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.