An altitude clearance misunderstanding near bwi.

Attributes
ACN	506180
Time
Date	200103
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : bwi.airport
State Reference	MD
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny.artcc
Operator	general aviation : personal
Make Model Name	Light Transport
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 70 flight time total : 5250 flight time type : 1500
ASRS Report	506180
Events
Anomaly	altitude deviation : overshoot non adherence : published procedure non adherence : clearance
Resolutory Action	controller : issued advisory controller : issued new clearance
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While being vectored for a visual approach to runway 33L at bwi we were flying level at 5000 ft and talking to baltimore approach. The next instruction received from approach was to descend and maintain 3000 ft. Upon reaching 3000 ft the controller said to maintain 3000 ft but that we should have stopped at 4000 ft. It is possible that he did say 4000 ft but both pilots thought he said 3000 ft and we did enter 3000 ft in the altitude selector.

Original NASA ASRS Text

Title: AN ALT CLRNC MISUNDERSTANDING NEAR BWI.

Narrative: WHILE BEING VECTORED FOR A VISUAL APCH TO RWY 33L AT BWI WE WERE FLYING LEVEL AT 5000 FT AND TALKING TO BALTIMORE APCH. THE NEXT INSTRUCTION RECEIVED FROM APCH WAS TO DSND AND MAINTAIN 3000 FT. UPON REACHING 3000 FT THE CTLR SAID TO MAINTAIN 3000 FT BUT THAT WE SHOULD HAVE STOPPED AT 4000 FT. IT IS POSSIBLE THAT HE DID SAY 4000 FT BUT BOTH PLTS THOUGHT HE SAID 3000 FT AND WE DID ENTER 3000 FT IN THE ALT SELECTOR.

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.