Corp aircraft has pressurization problem. Requests descent, cleared but descends below assigned.

Attributes
ACN	190022
Time
Date	199109
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mem
State Reference	TN
Altitude	msl bound lower : 12500 msl bound upper : 13000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 4800 flight time type : 100
ASRS Report	190022
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical altitude deviation : overshoot conflict : airborne less severe non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : declared emergency
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Depressurization at FL350. Leak at door seal. Contacted center and began rapid descent. Cleared to 13000 ft. Set altitude alert for 12000 ft. At 12500 center told us to return to 13000 ft. We had declared emergency before leaving FL350. May have had potential altitude conflict at 12000 ft. Set wrong altitude in the altitude alert.

Original NASA ASRS Text

Title: CORP ACFT HAS PRESSURIZATION PROBLEM. REQUESTS DSCNT, CLRED BUT DSNDS BELOW ASSIGNED.

Narrative: DEPRESSURIZATION AT FL350. LEAK AT DOOR SEAL. CONTACTED CENTER AND BEGAN RAPID DSCNT. CLRED TO 13000 FT. SET ALT ALERT FOR 12000 FT. AT 12500 CENTER TOLD US TO RETURN TO 13000 FT. WE HAD DECLARED EMER BEFORE LEAVING FL350. MAY HAVE HAD POTENTIAL ALT CONFLICT AT 12000 FT. SET WRONG ALT IN THE ALT ALERT.

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.