CE441 pilot has loss of pressurization, declares an emergency.

Attributes
ACN	555989
Time
Date	200207
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lex.airport
State Reference	KY
Altitude	msl single value : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	general aviation : corporate
Make Model Name	Conquest I/Conquest II
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	controller : radar pilot : commercial pilot : instrument pilot : multi engine
Experience	controller non radar : 2 controller radar : 7 flight time last 90 days : 110 flight time total : 2980 flight time type : 1500
ASRS Report	555989
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : provided flight assist flight crew : declared emergency other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

I was flying at FL290, when suddenly I noticed a popping in my ears. Right away I looked at the pressurization and confirmed that the cabin pressure was increasing rapidly, and the rate was indicating a decrease in the pressurization. I advised center that I needed an emergency descent. They advised me of a conflict in front of us at FL280 and they immediately gave us a turn to 040 degrees to avoid any conflict and they cleared us to any altitude that we needed. I initiated a turn from 005 degrees to 040 degrees to avoid the traffic and a descent to 12000 ft, where we regained normal cabin altitude of about 9000 ft. After completing all the published emergency procedures, and trying to figure out what had happened, we advised center of the situation and requested back on course to elkhart, in (our final destination). The mechanic next day was informed of the anomaly. After a few hours, he figured out that it was a wire going to the valve attached at the air cycle machine. This valve controls the amount of pressurization that goes into the air cycle machine. Apparently, the wire got too close to the air cycle machine and melted, which caused a short in the wire and shut the valve off. Everything worked properly, the masks were deployed automatically, and oxygen flow was indicated.

Original NASA ASRS Text

Title: CE441 PLT HAS LOSS OF PRESSURIZATION, DECLARES AN EMER.

Narrative: I WAS FLYING AT FL290, WHEN SUDDENLY I NOTICED A POPPING IN MY EARS. RIGHT AWAY I LOOKED AT THE PRESSURIZATION AND CONFIRMED THAT THE CABIN PRESSURE WAS INCREASING RAPIDLY, AND THE RATE WAS INDICATING A DECREASE IN THE PRESSURIZATION. I ADVISED CTR THAT I NEEDED AN EMER DSCNT. THEY ADVISED ME OF A CONFLICT IN FRONT OF US AT FL280 AND THEY IMMEDIATELY GAVE US A TURN TO 040 DEGS TO AVOID ANY CONFLICT AND THEY CLRED US TO ANY ALT THAT WE NEEDED. I INITIATED A TURN FROM 005 DEGS TO 040 DEGS TO AVOID THE TFC AND A DSCNT TO 12000 FT, WHERE WE REGAINED NORMAL CABIN ALT OF ABOUT 9000 FT. AFTER COMPLETING ALL THE PUBLISHED EMER PROCS, AND TRYING TO FIGURE OUT WHAT HAD HAPPENED, WE ADVISED CTR OF THE SIT AND REQUESTED BACK ON COURSE TO ELKHART, IN (OUR FINAL DEST). THE MECH NEXT DAY WAS INFORMED OF THE ANOMALY. AFTER A FEW HRS, HE FIGURED OUT THAT IT WAS A WIRE GOING TO THE VALVE ATTACHED AT THE AIR CYCLE MACHINE. THIS VALVE CTLS THE AMOUNT OF PRESSURIZATION THAT GOES INTO THE AIR CYCLE MACHINE. APPARENTLY, THE WIRE GOT TOO CLOSE TO THE AIR CYCLE MACHINE AND MELTED, WHICH CAUSED A SHORT IN THE WIRE AND SHUT THE VALVE OFF. EVERYTHING WORKED PROPERLY, THE MASKS WERE DEPLOYED AUTOMATICALLY, AND OXYGEN FLOW WAS INDICATED.

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.