Lear-31 captain reported unusually high cabin altitude; sudden air inflow; and fumes; possibly due t...

Attributes
ACN	1589618
Time
Date	201810
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Learjet 31
Operating Under FAR Part	Part 135
Flight Phase	Climb
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Pneumatic System Control
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 75 Flight Crew Total 3000 Flight Crew Type 1600
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Climbing through FL430; I noticed the cabin altitude was unusually high; approximately 8;500 feet; with a different pressure of ~7.5 psi. Suddenly; a large amount of air was forced into the cabin; lowering the inside cabin altitude by approximately 6;000 feet/minute. This was immediately followed by an increase in temperature. We suspected the emergency valves opened; and advised ATC to start us down lower. We ran the checklist for inadvertent activation of emergency airflow (I believe); then noticed fumes in the cockpit. It was then we decided to divert as soon as possible to ZZZ. No report of an emergency was ever made to ATC.

Original NASA ASRS Text

Title: Lear-31 Captain reported unusually high cabin altitude; sudden air inflow; and fumes; possibly due to inadvertent activation of emergency airflow.

Narrative: Climbing through FL430; I noticed the cabin altitude was unusually high; approximately 8;500 feet; with a different pressure of ~7.5 PSI. Suddenly; a large amount of air was forced into the cabin; lowering the inside cabin altitude by approximately 6;000 feet/minute. This was immediately followed by an increase in temperature. We suspected the emergency valves opened; and advised ATC to start us down lower. We ran the checklist for inadvertent activation of emergency airflow (I believe); then noticed fumes in the cockpit. It was then we decided to divert ASAP to ZZZ. No report of an emergency was ever made to ATC.

Data retrieved from NASA's ASRS site 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.

Lear-31 captain reported unusually high cabin altitude; sudden air inflow; and fumes; possibly due to inadvertent activation of emergency airflow.