A BE36 pilot reported an altitude deviation during approach to bwi.

Attributes
ACN	509330
Time
Date	200104
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : mumsy
State Reference	MD
Altitude	msl bound lower : 14300 msl bound upper : 15000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : phl.tower
Operator	general aviation : corporate
Make Model Name	Bonanza 36
Flight Phase	descent : approach
Route In Use	arrival star : westminster
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 5500 flight time type : 1000
ASRS Report	509330
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : far non adherence : published procedure
Resolutory Action	controller : issued new clearance flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was cleared to descend to and cross mumsy intersection at 15000 ft, while on the westminster arrival to bwi. I descended below the 15000 ft assigned altitude to 14300 ft before I recovered and climbed back up to 15000 ft. I was then cleared down to 11000 ft.

Original NASA ASRS Text

Title: A BE36 PLT RPTED AN ALTDEV DURING APCH TO BWI.

Narrative: I WAS CLRED TO DSND TO AND CROSS MUMSY INTXN AT 15000 FT, WHILE ON THE WESTMINSTER ARR TO BWI. I DSNDED BELOW THE 15000 FT ASSIGNED ALT TO 14300 FT BEFORE I RECOVERED AND CLBED BACK UP TO 15000 FT. I WAS THEN CLRED DOWN TO 11000 FT.

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.