A lancair 4P's pressurization malfunctioned climbing through FL210. The pilot declared an emergency;...

Narrative:

Climbing through FL210 for assigned altitude of FL220 experienced rapid depressurization and cabin altitude increase from approximately 8000 ft in 20;000 ft. Donned supplemental oxygen mask and attempted contact with center to obtain clearance for descent to lower altitude. Unable to contact center on either radio after several attempts. Changed transponder code to 7700 and began idle descent to VMC conditions. Passing approximately FL200 made contact with an air carrier (flight on same frequency) and requested relay to center. Through this intermediary I obtained clearance to 12;000 ft. Upon reaching 12;000 ft; cabin stabilized at 9000 ft and I was able to make direct contact with center. I terminated the emergency and returned to assigned transponder code. Airports below my position were solid IFR so I continued to destination (approximately 1 hour enroute) where VFR conditions prevailed and landed there without incident. Discrepancy was entered in the aircraft logbook.

Original NASA ASRS Text

Title: A Lancair 4P's pressurization malfunctioned climbing through FL210. The pilot declared an emergency; donned his oxygen mask; and began an emergency descent prior to ATC clearance because he was unable to make contact.

Narrative: Climbing through FL210 for assigned altitude of FL220 experienced rapid depressurization and cabin altitude increase from approximately 8000 FT in 20;000 FT. Donned supplemental oxygen mask and attempted contact with Center to obtain clearance for descent to lower altitude. Unable to contact Center on either radio after several attempts. Changed transponder code to 7700 and began idle descent to VMC conditions. Passing approximately FL200 made contact with an air carrier (flight on same frequency) and requested relay to Center. Through this intermediary I obtained clearance to 12;000 FT. Upon reaching 12;000 FT; cabin stabilized at 9000 FT and I was able to make direct contact with Center. I terminated the emergency and returned to assigned transponder code. Airports below my position were solid IFR so I continued to destination (approximately 1 hour enroute) where VFR conditions prevailed and landed there without incident. Discrepancy was entered in the aircraft Logbook.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	845024
Time
Date	200907
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Lancair Columbia
Operating Under FAR Part	Part 91
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Flight Engineer
Experience	Flight Crew Last 90 Days 40 Flight Crew Total 8000 Flight Crew Type 115
Events
Anomaly	Aircraft Equipment Problem Critical

A lancair 4P's pressurization malfunctioned climbing through FL210. The pilot declared an emergency; donned his oxygen mask; and began an emergency descent prior to ATC clearance because he was unable to make contact.