Flight crew of a DHC8 overshot assigned altitude on descent due to misunderstanding clearance.

Attributes
ACN	434357
Time
Date	199904
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : hto.vortac
State Reference	NY
Altitude	msl bound lower : 10400 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny.artcc
Operator	common carrier : air carrier
Make Model Name	Dash 8 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	cruise : enroute altitude change descent : intermediate altitude
Route In Use	enroute airway : v139.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 21000 flight time type : 13000
ASRS Report	434357
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 240 flight time total : 5000 flight time type : 700
ASRS Report	435270
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : far
Independent Detector	other controllera
Resolutory Action	flight crew : returned to assigned airspace
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The first officer and I both thought we had been cleared to descend to 10000 ft. When ATC asked us if we were going to stop at 11000 ft, we were at 10400 ft. When he asked this, we immediately climbed back to 11000 ft and nothing more was said. We both feel the initial clearance was to 10000 ft. I don't know what to do different. We try to read back any altitude changes by the book, but either us or the controller made a mistake.

Original NASA ASRS Text

Title: FLC OF A DHC8 OVERSHOT ASSIGNED ALT ON DSCNT DUE TO MISUNDERSTANDING CLRNC.

Narrative: THE FO AND I BOTH THOUGHT WE HAD BEEN CLRED TO DSND TO 10000 FT. WHEN ATC ASKED US IF WE WERE GOING TO STOP AT 11000 FT, WE WERE AT 10400 FT. WHEN HE ASKED THIS, WE IMMEDIATELY CLBED BACK TO 11000 FT AND NOTHING MORE WAS SAID. WE BOTH FEEL THE INITIAL CLRNC WAS TO 10000 FT. I DON'T KNOW WHAT TO DO DIFFERENT. WE TRY TO READ BACK ANY ALT CHANGES BY THE BOOK, BUT EITHER US OR THE CTLR MADE A MISTAKE.

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.