Flight crew of a B737-300 mishears descent clearance. Descends below assigned.

Attributes
ACN	337630
Time
Date	199606
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : vhp
State Reference	IN
Altitude	msl bound lower : 10500 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid tower : cle
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 9500 flight time type : 600
ASRS Report	337630
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : far
Independent Detector	other controllera
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

ATC gave us 3O mi south uhp at 11000 ft. We both thought they said 10000 ft and confirmed 10000 ft with each other. It wasn't till center called us back at 10500 ft that we were in error.

Original NASA ASRS Text

Title: FLC OF A B737-300 MISHEARS DSCNT CLRNC. DSNDS BELOW ASSIGNED.

Narrative: ATC GAVE US 3O MI S UHP AT 11000 FT. WE BOTH THOUGHT THEY SAID 10000 FT AND CONFIRMED 10000 FT WITH EACH OTHER. IT WASN'T TILL CTR CALLED US BACK AT 10500 FT THAT WE WERE IN ERROR.

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.