Lear 45 flight crew experienced loss of cabin pressure at FL430.

Attributes
ACN	836144
Time
Date	200905
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.VORTAC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Learjet 45
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 7000 Flight Crew Type 300
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Besides running 1 hour 30 minutes late due to ATC/weather; all was normal. While in cruise flight at FL430; we heard a rush of air and felt the cabin pressure change in our ears. The pressure controller showed a climb of 900 FPM. We immediately started an emergency descent. We squawked 7700 and advised ATC of the emergency. Passing FL350 the emergency pressurization valves activated. We continued the descent to 8000 feet. The cabin altitude never went above 9000 ft. This is because the back-up system (emergency press) worked correctly. We made the conservative choice to do the emergency descent procedures and troubleshoot later. We discussed diverting but chose to continue; as we were only 15 minutes from destination. When an emergency happens; there is little time for thinking or discussing. We were simply doing what we were trained to do.

Original NASA ASRS Text

Title: Lear 45 flight crew experienced loss of cabin pressure at FL430.

Narrative: Besides running 1 hour 30 minutes late due to ATC/weather; all was normal. While in cruise flight at FL430; we heard a rush of air and felt the cabin pressure change in our ears. The pressure controller showed a climb of 900 FPM. We immediately started an emergency descent. We squawked 7700 and advised ATC of the emergency. Passing FL350 the emergency pressurization valves activated. We continued the descent to 8000 feet. The cabin altitude never went above 9000 FT. This is because the back-up system (EMER PRESS) worked correctly. We made the conservative choice to do the emergency descent procedures and troubleshoot later. We discussed diverting but chose to continue; as we were only 15 minutes from destination. When an emergency happens; there is little time for thinking or discussing. We were simply doing what we were trained to do.

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.