#23 – GROUND
PRESSURIZATION CHECKLIST
FIRST,
ANYTIME THE AIRCRAFT IS STARTED, THE DV WINDOW MUST
BE OPEN. THIS IS BECAUSE BOTH BLEED SWITCHING VALVES (BSV’S)
ARE FAILED OPEN, AND THEY REQUIRE ELECTRICAL POWER AND BLEED AIR PRESSURE TO CLOSE.
THEREFORE, AIR IS BEING PUMPED INTO THE CABIN AS SOON AS THE ENGINE IS CRANKED,
AND NOT ENOUGH VACUUM IS GENERATED AT THE VENTURI TO OPEN THE SAFETY VALVE.
SECOND, KEEP
THE OUTFLOW VALVES CLEAN. USE MILD SOAP OR ISOPROPYL ALCOHOL TO WIPE THE KNIFE
EDGE SEAL AND SURROUNDING AREA.
THIRD, SPRAY
A LITTLE LPS-1 INTO THE VENT HOLE ON THE OUTFLOW VALVE AND PUSH UP THE VALVE
AND SPRAY THE SHAFT AREA ALSO.
FOURTH, USE
THE GROUND PRESSURIZATION BUTTON. IF YOURS DOES NOT WORK, GET IT FIXED.
GROUND PRESSURIZING THE WESTWIND:
CHECK THE
FOLLOWING FIRST BEFORE CLOSING THE ISOBARIC VALVE.
1.
THE
2.
GROUND
PRESSURIZATION BUTTON USED-
3.
TRIP
THE LEFT MAIN LANDING GEAR SQUAT SWITCH TO FLIGHT POSITION -- SAFETY VALVE
CLOSES FULLY AND
INFORMATION ONLY – THE MANUAL DUMP VALVE ONLY CONTROLS
THE SAFETY VALVE WITH VACUUM FROM THE EJECTOR ON FORWARD PRESSURE BULKHEAD. YOU
MUST HAVE THE ENGINES RUNNING AND ALL DOORS AND DV
WINDOW SHUT.
TO PRESSURIZE:
1.
CUT
SAFETY WIRE AND CLOSE THE ISOBARIC VALVE.
2.
OPEN
THE MANUAL DUMP VALVE FULLY.
3.
START
BOTH ENGINES.
4.
SELECT
BOTH ON BLEED SOURCE SELECTOR.
5.
CLOSE
THE DV WINDOW SLOWLY.
6.
PULL
THE LH PRESSURIZATION CIRCUIT BREAKER.
7.
FULLY
CLOSE THE MANUAL DUMP VALVE.
8.
YOU
MAY HAVE TO INCREASE ENGINE SPEED OR TOGGLE TEMP TO HOT TO REACH MAX
DIFFERENTIAL, BUT IT SHOULD GET THERE AND OPERATE ON THE LIMITERS OF THE
OUTFLOW VALVES.
9.
SLOWLY
OPEN THE MANUAL DUMP TO BLEED THE CABIN TO AMBIENT PRESSURE.
10. RESET ALL CIRCUIT BREAKERS AND RE-OPEN
THE ISOBARIC VALVE AND SAFETY WIRE IT.
NOTE: IF YOU WANT TO CHECK YOUR CABIN LEAKAGE RATE, LEAVE THE
AIRCRAFT PRESSURIZED AND SHUT DOWN BOTH ENGINES. SEE HOW LONG IT TAKES THE
AIRCRAFT TO RETURN TO AMBIENT PRESSURE.