ais 1st sem prelim quiz 2 (static pressure to suction gauge)

Static Pressure

Pressure that is exerted equally in all directions by the weight of the air above it.

Dynamic Pressure Factors

Dynamic pressure increases as both airflow speed and air density increase.

Total Pressure

The sum of static pressure and dynamic pressure (P{total} = P{static} + P_{dynamic}).

Pitot Tube

The specific aircraft component designed to collect dynamic (impact) pressure.

Static Port Location

Positioned on the aircraft fuselage in an area where airflow disturbance is minimal to ensure accurate static pressure readings.

Instruments: Airspeed Indicator (Pitot-Static)

The only pressure instrument connected to both the pitot tube and the static port; it measures the difference through a diaphragm.

Static Pressure and Altitude Relationship

As an aircraft climbs, static pressure decreases; conversely, an increase in static pressure indicates a decrease in altitude.

Airspeed Indicator: Green Arc

Represents the normal operating range of the aircraft.

Airspeed Indicator: Red Line

The never-exceed speed (V_{NE}); flying above this limit may result in structural damage.

Airspeed Indicator: White Arc

Indicates the flap operating range.

Pitot System Blockage: Drain Open

If the pitot head is blocked but the drain hole remains open, the airspeed indicator will decrease to zero.

Pitot System Blockage: Head and Drain Blocked

During a climb, if both the pitot head and drain hole are blocked, the airspeed indicator will over-read (acting like an altimeter).

Altimeter Mechanism

An instrument that measures altitude using static pressure only; it contains aneroid wafers that expand or contract.

Static Port Blockage (Altimeter Impact)

If the static port becomes completely blocked, the altimeter will remain frozen at the last known altitude.

Kollsman Window

The part of the altimeter that allows pilots to adjust the instrument to the local barometric pressure setting.

Suction Gauge and Vacuum System

Shows the operating pressure of the vacuum system; the normal range is typically highlighted by a green arc between 4.5 and 5.4 \text{ inHg}.

Effects of Abnormal Suction Pressure

Low suction pressure makes gyroscopic instruments (like the Heading and Attitude Indicators) unreliable, while high pressure may damage the gyroscopes.