Loss of cabin pressurization system. Excessive cabin altitude resulting in emergency descent.

Attributes
ACN	113911
Time
Date	198906
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sgf
State Reference	MO
Altitude	msl bound lower : 10000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other cruise other descent other
Route In Use	enroute airway : zkc
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 7000 flight time type : 1500
ASRS Report	113911
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Climbing through FL310 en route to FL410 the aircraft pressurization controller failed. I leveled the aircraft at FL310 while the copilot attempted to arrest the cabin climb rate through use of the manual system. This did not adequately stop the climb rate so the flight crew donned the oxygen masks and initiated a rapid descent. While in the descent we communicated to ATC that we were descending and required a lower altitude. They asked if we would like 10,000' and we responded with an affirmative answer. The flight continued at 10,000' to its destination with no further occurrences. The purpose of my report is to let you know that we stopped our climb at FL310 and initiated a rapid descent before a clearance to a lower altitude was received.

Original NASA ASRS Text

Title: LOSS OF CABIN PRESSURIZATION SYSTEM. EXCESSIVE CABIN ALT RESULTING IN EMERGENCY DESCENT.

Narrative: CLIMBING THROUGH FL310 ENRTE TO FL410 THE ACFT PRESSURIZATION CTLR FAILED. I LEVELED THE ACFT AT FL310 WHILE THE COPLT ATTEMPTED TO ARREST THE CABIN CLIMB RATE THROUGH USE OF THE MANUAL SYSTEM. THIS DID NOT ADEQUATELY STOP THE CLIMB RATE SO THE FLT CREW DONNED THE OXYGEN MASKS AND INITIATED A RAPID DSCNT. WHILE IN THE DSCNT WE COMMUNICATED TO ATC THAT WE WERE DESCENDING AND REQUIRED A LOWER ALT. THEY ASKED IF WE WOULD LIKE 10,000' AND WE RESPONDED WITH AN AFFIRMATIVE ANSWER. THE FLT CONTINUED AT 10,000' TO ITS DEST WITH NO FURTHER OCCURRENCES. THE PURPOSE OF MY REPORT IS TO LET YOU KNOW THAT WE STOPPED OUR CLIMB AT FL310 AND INITIATED A RAPID DSCNT BEFORE A CLRNC TO A LOWER ALT WAS RECEIVED.

Data retrieved from NASA's ASRS site as of August 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.