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Gulfstream V Training Captain's Questions and Answers

 FlightSafety KSAV

CABIN PRESSURE CONTROL PANEL

What is the power source of the AUTO / SEMI pressure selection switch?

Channel 1 – ESS AC BUS
Channel 2 – RIGHT MAIN AC BUS

When does the Pressurization Computer switch channels?

When the Airstair door or Baggage door is cycled open then closed.

Is there any way we can switch Pressurization Channels?

Yes, by selecting and deselecting Manual.

Is there any way to determine which channel of the pressurization controller is active?

Yes, by viewing the ECS / PRESS Synoptic page, lower right corner.

How do you switch from AUTO to SEMI?

Manually select to SEMI.

When will the FLIGHT / LANDING switch go to FLIGHT?

1. When the aircraft ground speed exceeds 8 knots
2. Large Power Changes while taxing
3. If selected

Where does the Pressurization System obtain altitude information?

Flight Management System and MADC

Where does the Pressurization System obtain Landing Field Elevation information?

The Flight Management System computer Flight Plan

When does the FLIGHT / LANDING switch change to LANDING?

During descent, change of Altitude of more than 1000 feet.

What happens to the FLIGHT / LANDING if the aircraft levels off after descent begins?

The Pressurization system will continue to pressurize the aircraft after 1 minute to a DEFAULT pressure mode of 10.17 PSID. However, the FLIGHT LANDING switch will still indicate LANDING.

How can we ensure that the Pressurization System is pressurizing the cabin at the proper cabin pressure differential?

Reselect the FLIGHT / LANDING switch to FLIGHT.

What happens to the FLIGHT / LANDING switch if the aircraft climbs?

The pressurization system will begin to repressurize the aircraft. However, the FLIGHT / LANDING switch will continue to indicate LANDING, unless manually selected to FLIGHT.

How do we control aircraft pressurization in the SEMI mode?

By presetting all information on the CABIN PRESSURE SELECTOR PANEL located on the center console.

How can we tell if the channels switched or which channel the pressurization system is in?

Information located on the Lower Right Corner of the ECS / PRESS synoptic page, or SUMMERY synoptic page.

How do we control aircraft pressurization in the MANUAL mode?

By manipulating the Manual Hold Rate Knob that controls the DC motor to open and close the OUTFLOW valve.

How do we know how much the aircraft is climbing or descending by using the MANUAL Rate Knob?

By observing the Cabin Pressure Indicator Panel £ 500 FPM.
ECS / PRESS Synoptic page Rate of Change box on bottom of page.

What will activate the AUTOMATIC EMERGENCY DESCENT MODE?

red CABIN PRESSURE LOW message.

What are the set points of the red CABIN PRESSURE LOW message?

8,000, 10,000, and 14,500 feet
If the LFE ‹ 7,500 feet the trip point is 8,000 feet. If the LFE is between 7,500 and 9,400 feet, the trip point is 10,000 feet. And if the LFE ³ 9,400, the trip point is 14,500

What is the trip point of the EDM if you are in the MANUAL MODE?

10,000 feet

Describe the Automatic Emergency Descent Mode.

1. Aircraft ≥ 40,000 feet
2. Auto Pilot and Auto Throttles Engaged
3. CABIN PRESSURE LOW red message
4. Aircraft Turns 90° Left of Present Course
5. Descends to 15,000 feet
6. Speed set at VMO / MMO 340 KCAS
7. Upon reaching 15,000 feet, aircraft speed is 250 KCAS, remaining at the 90° off set course

If you are planning a GV Flight from a low altitude airport to a high altitude airport (La Pas), How will the Cabin pressurization system function?

The Cabin Pressurization (in AUTO) will climb the cabin to 8000 feet until you begin descent; at which time the cabin will climb to the Landing Field Elevation. 

How can you set the cabin to a more Comfortable Cabin Altitude in the above example?

Once you reach your cruise altitude, select the AUTO / SEMI Switch to SEMI, then use the Cabin Pressure Selector Panel (on the Center Console) to set a more desirable Cabin Altitude (i. e. 6000 feet). At TOD, deselect the AUTO / SEMI switch back to AUTO, the aircraft cabin will climb to the La Pas Landing Field Elevation.

What are the Cabin Differential Pressure Limits?

• 10.48
• 0.3
• Access to the Baggage Compartment is limited to 5 minute access above 40,000 feet and is prohibited above 45,000 feet during single PAC operations.