Instruments (1-50)

A pitot head is used to measure:

• dynamic minus static pressure

• static plus dynamic pressure

• static pressure

• dynamic pressure

Manoeuvre induced error:

• is caused by pressure changes at static probes or vents

• is likely to be greatest when yawing after engine failure

• is combined with instrument and position error on a correction card

• lasts for only a short time at high altitude

Fitting static vents to both sides of the aircraft fuselage will:

• reduce the position error

• balance out errors caused by side-slipping or yawing

• require a calibration card for each static vent

• enable a greater number of instruments to be fitted

A remote reading thermometer depends on .... to indicate changes in temperature:

• change of electrical resistance of the two metals

• change of electrical resistance with temperature

• change of electrical resistance with pressure

• change of electrical capacitance with temperature

An air temperature probe may be aspirated in order to:

• prevent icing

• measure air temperature on the ground

• compensate for moisture level at the ramp position

• reduce the effects of solar radiation

A pitot blockage of both the ram air input and the drain hole with the static port open causes the airspeed indicator to:

• read a little low

• read a little high

• react like an altimeter

• freeze at zero

If the static line to the ASI becomes blocked during a long descent, a dangerous situation could arise due to the ASI:

• over-reading, this indicated speed falsely showing the aircraft to be further from the stalling speed than it actually is

• under-reading, this indicated speed falsely showing the aircraft to be closer to the stalling speed than it actually is

• under-reading, this indicated speed possibly leading to the operation of flaps and/or landing gear at speeds in excess of safety speeds

• over-reading, this indicated speed possibly leading to the operation of flaps and/or landing gear at speeds in excess of safety speeds

The airspeed indicator is calibrated to:

• conditions of the International Standard Atmosphere at all heights

• conditions of the International Standard Atmosphere at MSL

• an air density of 1013.25 g/m3

• indicate correctly in any atmosphere

If the static line to the ASI becomes blocked during a climb, the ASI reading will:

• increase, no matter what the actual airspeed is

• progressively under indicate the value of airspeed

• progressively over indicate the value of airspeed

• stick at the airspeed showing at the moment of blockage

An aircraft taking off from an airfield with QNH set on the altimeter has both static vents blocked by ice. As the aircraft climbs away the altimeter will:

• read the airfield elevation

• indicate the aircraft height amsl

• read the height of the aircraft above the airfield

• show only a very small increase in height