Flight Instrument Flashcards

If the pitot tube and outside static vents become clogged, which instruments would be affected?

Answer: The altimeter, airspeed indicator, and vertical speed indicator.

The pitot-static system provides crucial pressure inputs to several flight instruments. The pitot tube supplies ram air pressure to the airspeed indicator, while the static vents provide ambient atmospheric pressure to the airspeed indicator, altimeter, and vertical speed indicator. Therefore, a blockage in both the pitot tube and static vents would render all three of these instruments inoperative or provide erroneous readings.

Which instrument will become inoperative if the pitot tube becomes clogged?

Answer: Airspeed.

The pitot tube is specifically designed to measure ram air pressure, which is the dynamic pressure created by the aircraft's forward motion. This ram air pressure is then compared with static pressure to determine airspeed. If the pitot tube becomes clogged, the airspeed indicator will lose its primary pressure source and become inoperative or display incorrect readings.

Which instrument(s) will become inoperative if the static vents become clogged?

Answer: Airspeed, altimeter, and vertical speed.

The static vents provide ambient atmospheric pressure to the altimeter, vertical speed indicator, and the static side of the airspeed indicator. If these vents become clogged, the altimeter will freeze at the altitude where the blockage occurred, the vertical speed indicator will read zero, and the airspeed indicator will provide erroneous readings because it relies on both pitot and static pressure for accurate operation.

Altimeter 1 indicates

Answer: 10,500 feet.

Altimeters typically have three hands: a short, thick hand for thousands of feet, a long, thin hand for hundreds of feet, and a very thin hand for tens of thousands of feet. For Altimeter 1, the very thin hand points to 1 (indicating 10,000 feet), the short, thick hand points to 0 (indicating 0 thousands), and the long, thin hand points to 5 (indicating 500 feet). Combining these gives 10,000 + 500 = 10,500 feet.

Altimeter 2 indicates

Answer: 14,500 feet.

For Altimeter 2, the very thin hand points to 1 (indicating 10,000 feet), the short, thick hand points to 4 (indicating 4,000 feet), and the long, thin hand points to 5 (indicating 500 feet). Summing these values gives 10,000 + 4,000 + 500 = 14,500 feet.

Altimeter 3 indicates

Answer: 9,500 feet.

For Altimeter 3, the very thin hand is between 0 and 1, indicating less than 10,000 feet. The short, thick hand points to 9 (indicating 9,000 feet), and the long, thin hand points to 5 (indicating 500 feet). Therefore, the altimeter indicates 9,000 + 500 = 9,500 feet.

Which altimeter(s) indicate(s) more than 10,000 feet?

Answer: 1 and 2 only.

Based on the readings, Altimeter 1 indicates 10,500 feet and Altimeter 2 indicates 14,500 feet, both of which are greater than 10,000 feet. Altimeter 3 indicates 9,500 feet, which is less than 10,000 feet. Therefore, only altimeters 1 and 2 indicate more than 10,000 feet.

Altimeter setting is the value to which the barometric pressure scale of the altimeter is set so the altimeter indicates

Answer: true altitude at field elevation.

The altimeter setting, often referred to as the local barometric pressure, is adjusted in the Kollsman window of the altimeter. Setting the altimeter to the correct local pressure ensures that the instrument accurately displays the aircraft's true altitude (height above mean sea level) when on the ground at a known field elevation. This correction accounts for variations in atmospheric pressure from the standard atmosphere.

How do variations in temperature affect the altimeter?

Answer: A. Pressure levels are raised on warm days and the indicated altitude is lower than true altitude.

On warm days, the air is less dense and expands, causing pressure levels to be higher than they would be in a standard atmosphere. Since the altimeter is calibrated for a standard atmosphere, it will indicate a lower altitude than the aircraft's actual true altitude. This is a critical concept for pilots: 'High to low, look out below; hot to cold, don't be so bold.'

What is true altitude?

Answer: The vertical distance of the aircraft above sea level.

True altitude is the actual vertical distance of an aircraft above Mean Sea Level (MSL). It is the real height of the aircraft above the average level of the ocean. While indicated altitude is read directly from the altimeter, true altitude requires correction for non-standard temperature and pressure conditions.

What is absolute altitude?

Answer: The vertical distance of the aircraft above the surface.

Absolute altitude refers to the actual vertical distance of an aircraft above the terrain or ground directly beneath it. This is often referred to as AGL (Above Ground Level). Unlike true altitude (above MSL), absolute altitude provides a direct measure of clearance from obstacles on the surface.

What is pressure altitude?

Answer: The altitude indicated when the barometric pressure scale is set to 29.92.

Pressure altitude is the altitude indicated by an altimeter when its barometric pressure scale is set to the standard atmospheric pressure of 29.92 inches of mercury (or 1013.2 millibars). It represents the height above the standard datum plane, which is a theoretical level where the atmospheric pressure is 29.92 inHg. Pressure altitude is used for aircraft performance calculations and for flight at high altitudes (above 18,000 feet MSL).

Under what condition is indicated altitude the same as true altitude?

Answer: When at sea level under standard conditions.

Indicated altitude, read directly from the altimeter, matches true altitude (actual height above MSL) only under specific conditions. This occurs when the aircraft is at sea level, and the atmospheric conditions (temperature and pressure) precisely match the International Standard Atmosphere. Any deviation from standard temperature or pressure will cause a difference between indicated and true altitude.

If it is necessary to set the altimeter from 29.15 to 29.85, what change occurs?

Answer: 700-foot increase in indicated altitude.

When adjusting the altimeter setting, remember the rule: 'From low to high, look to the sky.' An increase in the altimeter setting (from 29.15 to 29.85) means the altimeter will indicate a higher altitude. The difference in setting is 0.70 inches of mercury (29.85 - 29.15). Since each 0.01 inch of mercury typically equates to about 10 feet of altitude, a 0.70-inch change results in a 700-foot increase in indicated altitude (0.70 * 1000 = 700 feet).

The pitot system provides impact pressure for which instrument?

Answer: Airspeed indicator.

The pitot tube is a crucial component of the pitot-static system, specifically designed to capture ram air pressure (impact pressure) as the aircraft moves through the air. This dynamic pressure is then fed to the airspeed indicator, where it is compared against static pressure to accurately measure the aircraft's speed relative to the surrounding air.

A turn coordinator provides an indication of the

Answer: movement of the aircraft about the yaw and roll axes.

The turn coordinator is a gyroscopic instrument that senses both the rate of roll and the rate of yaw. The miniature aircraft on the display indicates the rate of roll when entering or exiting a turn, and then stabilizes to show the rate of turn. The inclinometer (ball) indicates the quality of the turn, specifically whether it is coordinated or slipping/skidding, which relates to yaw.

To receive accurate indications during flight from a heading indicator, the instrument must be

Answer: periodically realigned with the magnetic compass as the gyro precesses.

The heading indicator (directional gyro) is a gyroscopic instrument that provides a stable heading reference, free from the oscillations and errors of a magnetic compass. However, due to a phenomenon called precession, the gyro slowly drifts over time. Therefore, pilots must periodically check and realign the heading indicator with the magnetic compass to ensure its accuracy throughout the flight.

The proper adjustment to make on the attitude indicator during level flight is to align the

Answer: miniature airplane to the horizon bar.

The attitude indicator displays the aircraft's pitch and bank relative to an artificial horizon. During level flight, the miniature airplane symbol should be aligned with the horizon bar to accurately represent the aircraft's attitude. This adjustment, typically made using a set knob, ensures the instrument provides a correct visual reference for the pilot.