Flight Instruments

Static port blockage

Airspeed indicator - Indicates correctly only at the blockage altitude

• Higher altitudes - indicates lower than it should

• Lower altitudes - Indicates higher than it should

Altimeter - Freezes on the altitude where it was blocked

VSI - Freezes on zero

• When blockage occurs using an alt static source of pressure or break the VSI window this may result in reverse VSI indications

Alt static air instrument indications

Alt static air means lower static pressure is measured

Airspeed - Indicates faster speed than it should

Altimeter - Indicates higher than it should

VSI - Momentarily shows a climb

Pitot tube blockage

Ram inlet clogged and drain hole open - ASI goes to zero

Both air inlet and drain hole clogged - ASI acts as altimeter

What is the rate of turn of the aircraft dependent (regardless of airspeed) on?

Horizontal component of lift by increasing bank

Skidding and slipping turns

Skidding turn - (Tail of aircraft being slung to the outside by CF) - CF > HL-

• Load factor increases

Slipping turn - (Wings of aircraft being slung to the outside by HL) - HL > CF

• Load factor decreases

Turn and slip

Gyro in turn and slip is electric

1. Rate of turn

2. Quality of turn

Turn Coordinator

Gyro in turn coordinator at an angle which allows for

1. Rate of turn of the aircraft

2. Quality of the turn (correct angle of bank for rate of turn)

3. Roll rate (by showing how fast the miniature airplane moves)

4. Bank attitude of airplane (indirect as angle of bank increases turn coordinator is displaced more around its gyro and the miniature aircraft shows a greater deflection or turn)

Heading indicator

Stable, not subject to errors of mag compass

Heading reference - Stays in the same position during flight

Friction and earth’s rotation cause the gyro to preccess and so we need to realign it every 15min

Attitude indicator

CF causes the gyro to precess to the inside of the turn

180* turn - Slight pitch up and slight turn in the opposite direction
360* turn - Error cancels itself out
Skidding turn - Slight turn in the opposite direction

Acceleration - Slight pitch up (dangerous on TO)
Deceleration - Slight pitch down

Compass Turns

Left turn on the turn coodinator - Lower your heading
Right turn on the turn coordinator - Raise your heading

Overshoot the heading for southerly headings by an additional 10* per each 30* increment of heading you are turning to starting with 0* overshoot at W or E