LR45 suffers loss of cabin pressurization. Makes emergency descent and diverts.

Attributes
ACN	785953
Time
Date	200805
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl bound lower : 43000 msl bound upper : 45000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	general aviation : corporate
Make Model Name	Learjet 45
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 80 flight time total : 7400 flight time type : 500
ASRS Report	785953
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : cas wng other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During cruise flight; the crew was alerted by the master caution; chime; and amber cabin altitude cas message that indicated that the aircraft had a pressurization problem. This was confirmed by observing an increase in cabin altitude on the pressurization panel. At this point the PF advised the PNF to also don his mask. While the PF monitored cabin pressure; the PNF began executing the cabin altitude checklist. PF monitored cabin pressure altitude; which continued to climb and advised PNF to request lower altitude. After initially executing a normal descent; the cabin pressure began to rapidly increase; at which time the decision to initiate an emergency descent was made. ATC was advised that we had initiated emergency descent and we requested alternate landing instructions. ATC advised us that ZZZ would be a good alternate for our condition and also advised us; if able; to turn 20 degrees right for traffic; which we were able to comply with. We made a decision to go ahead and divert to ZZZ as advised by ATC. After leveling at 10000 ft; ATC gave us instruction to turn to a heading of 070 degrees direct to ZZZ; which we complied with. During preparation for landing; we then received a cas message indicating a cabin attendant duct overheat; at which point the PNF started executing the cabin attendant duct overheat checklist while the PF requested ATC to direct us to the nearest airport with a 6000+ ft runway and declared an emergency. After completing the checklist; the PNF advised the PF that the problem had been resolved; at which time we requested continuing on to ZZZ. At this time; the entire emergency checklist had been executed and completed. We then completed a normal landing without incident or injury to crew and passenger. We exited the active and requested taxi instructions to the nearest FBO. PNF removed passenger from the aircraft and escorted them to the FBO lobby while the PF secured the aircraft. PNF advised emt personnel to come in and give assistance to the passenger if it became necessary.

Original NASA ASRS Text

Title: LR45 SUFFERS LOSS OF CABIN PRESSURIZATION. MAKES EMERGENCY DESCENT AND DIVERTS.

Narrative: DURING CRUISE FLT; THE CREW WAS ALERTED BY THE MASTER CAUTION; CHIME; AND AMBER CABIN ALT CAS MESSAGE THAT INDICATED THAT THE ACFT HAD A PRESSURIZATION PROB. THIS WAS CONFIRMED BY OBSERVING AN INCREASE IN CABIN ALT ON THE PRESSURIZATION PANEL. AT THIS POINT THE PF ADVISED THE PNF TO ALSO DON HIS MASK. WHILE THE PF MONITORED CABIN PRESSURE; THE PNF BEGAN EXECUTING THE CABIN ALT CHKLIST. PF MONITORED CABIN PRESSURE ALT; WHICH CONTINUED TO CLB AND ADVISED PNF TO REQUEST LOWER ALT. AFTER INITIALLY EXECUTING A NORMAL DSCNT; THE CABIN PRESSURE BEGAN TO RAPIDLY INCREASE; AT WHICH TIME THE DECISION TO INITIATE AN EMER DSCNT WAS MADE. ATC WAS ADVISED THAT WE HAD INITIATED EMER DSCNT AND WE REQUESTED ALTERNATE LNDG INSTRUCTIONS. ATC ADVISED US THAT ZZZ WOULD BE A GOOD ALTERNATE FOR OUR CONDITION AND ALSO ADVISED US; IF ABLE; TO TURN 20 DEGS R FOR TFC; WHICH WE WERE ABLE TO COMPLY WITH. WE MADE A DECISION TO GO AHEAD AND DIVERT TO ZZZ AS ADVISED BY ATC. AFTER LEVELING AT 10000 FT; ATC GAVE US INSTRUCTION TO TURN TO A HDG OF 070 DEGS DIRECT TO ZZZ; WHICH WE COMPLIED WITH. DURING PREPARATION FOR LNDG; WE THEN RECEIVED A CAS MESSAGE INDICATING A CAB DUCT OVERHEAT; AT WHICH POINT THE PNF STARTED EXECUTING THE CAB DUCT OVERHEAT CHKLIST WHILE THE PF REQUESTED ATC TO DIRECT US TO THE NEAREST ARPT WITH A 6000+ FT RWY AND DECLARED AN EMER. AFTER COMPLETING THE CHKLIST; THE PNF ADVISED THE PF THAT THE PROB HAD BEEN RESOLVED; AT WHICH TIME WE REQUESTED CONTINUING ON TO ZZZ. AT THIS TIME; THE ENTIRE EMER CHKLIST HAD BEEN EXECUTED AND COMPLETED. WE THEN COMPLETED A NORMAL LNDG WITHOUT INCIDENT OR INJURY TO CREW AND PAX. WE EXITED THE ACTIVE AND REQUESTED TAXI INSTRUCTIONS TO THE NEAREST FBO. PNF REMOVED PAX FROM THE ACFT AND ESCORTED THEM TO THE FBO LOBBY WHILE THE PF SECURED THE ACFT. PNF ADVISED EMT PERSONNEL TO COME IN AND GIVE ASSISTANCE TO THE PAX IF IT BECAME NECESSARY.

Data retrieved from NASA's ASRS site as of May 2009 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.