Chapter 8 Flight Instruments

Flight Instruments

What does the pitot tube do?

Measures the total moving pressure in the air. (dynamic pressure)

Static pressure also known as ambient pressure does?

Always present whether aircraft is moving or at rest. Simply the barometric pressure in the area. Dynamic pressure is only present when aircraft is moving; therefore, it can be thought of as pressure due to motion.

What instruments need a clear pitot tube in order to be read?

Vertical speed indicator, altimeter, and air speed indicator

Indicated altitude

read directly from the altimeter uncorrected

True altitude

vertical distance aircraft is above sea level or above means sea level

Absolute altitude

vertical distance above terrain or ground level AGL

Pressure altitude and density altitude

29.92 hg, pressure altitude corrected for standard temperature

Density altitude

ASI air speed indicator works because of the

pitot and static system

ASI white arc

within flap operation

ASI lower limit of white arc

Vso - stall speed. With gear and flaps down.

ASI upper limit of white arc

Vfe - maximum speed with flaps extended

ASI lower limit of green arc

Vs1 - stall speed with gear and flaps up

ASI Upper limit of green arc

Vno - maximum structural cruising speed

ASI yellow arc

caution range

ASI red line

never exceed speed

Design maneuvering speed

Va - maximum speed which structural design limitation loads can be imposed without causing structural damager. Differs by weight.

VLO

landing gear operating speed. maximum speed for extending or retracting the landing gear if flying an aircraft with retractable gear

VLE

landing geare extended speed. maximum speed at which an aircraft can be flown with landing gear extended

VX

best angle of climb speed. Greatest amount of altitude gain in a short distance.

VY

best rate of climb. airspeed that gains the most altitude in a given amount of time.

VYSE

single engine best rate of climb.

VMC

minimum control speed. minimum flight speed at which a light, twin-engine aircraft can be satisfactory controlled when an engine suddenly becomes inoperative and the remaining engine is at takeoff power.

To remember rudder alignment in slip and turn coordinator remember

step on the ball

Inaccuracies in the heading indicator

because the earth is rotating 15 degrees an hour the heading indicator maybe of by 15 degrees

What is variation?

The difference between true and magnetic compass.

Describe the magnetic compass.

Is backwards to read because the card stays stationary while the pilot rotates around it. The white mark is called the lubber and the big ticks are 10 degrees half ticks are 5 degrees.

Agonic line

anywhere on this line the two poles are aligned and there is no variation. East of this line the magnetic north pole is to the west of the geographic North Pole and correction must be applied to get true direction.

What is deviation?

causes compass error due to the aircraft having metals

ANDS

acceleration north/deceleration south

lag and lead