Results
#1. If the pitot line to an ASI becomes totally blocked during a climb, the ASI reading will:
remember
Pitot
Over read
Climb
Under read
Descent
Static
Under read
Climb
Over read
Descent
#2. Compressibility error:
Compressibility error always causes the airspeed indicator to overread at a True Airspeed (TAS) of 300 knots or above. This happens because, at such high speeds, the air entering the Pitot tube is brought to rest and compressed. As a result, the total pressure measured by the Pitot tube increases, leading the airspeed indicator to show a higher airspeed than the actual TAS. This error becomes more significant as speed increases due to the increased effect of air compression in the Pitot system.
#3. If the static line to the ASI becomes blocked during a long descent, a dangerous situation could arise due to the ASI:
remember
Pitot
Over read
Climb
Under read
Descent
Static
Under read
Climb
Over read
Descent
#4. An aircraft maintaining a constant CAS and altitude is flying from a cold airmass into warmer air. The effect of the change of temperature on the speed will be:
When an aircraft maintains a constant Calibrated Airspeed (CAS) and altitude while flying from a cold airmass into warmer air, the True Airspeed (TAS) will increase. This happens because air density decreases as the temperature rises, meaning that for the same CAS, the aircraft is actually flying faster through the air.
In summary, flying from cold air into warmer air will cause the aircraft’s TAS to increase while maintaining constant CAS and altitude
#5. The airspeed indicator is calibrated to:
The airspeed indicator is calibrated to the conditions of the International Standard Atmosphere (ISA) at Mean Sea Level (MSL), which are as follows:
- Pressure: 1013.25 hPa (hectopascals) or 29.92 inHg
- Temperature: 15°C (59°F)
- Density: 1.225 kg/m³
- Acceleration due to gravity (g): 9.80665 m/s²
#7. Excluding blockages, the full list of errors of the ASI is:
- Instrument Error: Inaccuracies within the ASI due to imperfections in the instrument’s design or manufacturing tolerances.
- Position Error: Caused by the location of the pitot tube and static ports on the aircraft, leading to airflow disturbances that result in incorrect pressure measurements.
- Density Error: The ASI assumes standard atmospheric density, so changes in altitude, temperature, or pressure can cause incorrect readings, as the actual air density varies from the standard.
- Compressibility Error: At high airspeeds, the air compresses as it enters the pitot tube, which causes the ASI to overread, particularly at speeds above 300 knots.
- Manoeuvre-Induced Error: Occurs during sharp turns or rapid altitude changes, where pressure variations lead to temporary inaccuracies in the ASI readings.
to remember the errors remember BLIP DC
To remember the errors of the ASI, use the mnemonic BLIP DCM:
- B: Blockage error
- L: Leakage error
- I: Instrument error
- P: Position error
- D: Density error
- C: Compressibility error
- Manoeuvre-Induced Error
#8. Some ASIs have coloured arcs and lines marked on their dials. A yellow arc and a white arc indicate:
In airspeed indicators (ASIs), the colored arcs and lines typically signify specific speed ranges. Here’s what the yellow and white arcs usually indicate:
- Yellow Arc: This arc often represents the caution range. It indicates speeds where the aircraft may be operating in a potentially hazardous manner, such as near stall speeds or structural limitations.
- White Arc: This arc represents the flap operating range. It indicates the speeds at which flaps can be safely extended and retracted, usually encompassing the flap extension speed (VFE) and the flap retraction speed (VFR).
#9. What will be the TAS if cruising altitude is 39 000 ft, temperature is ISA +5 and CAS 200 kt:
#10. If the static line to the ASI becomes blocked during a climb, the ASI reading will:
remember
Pitot
Over read
Climb
Under read
Descent