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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the formula for kinetic energy? What’s another word for kinetic energy? |
KE = 1/2xair density x TAS^2 KE is also called dynamic pressure |
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In an emergency if static ports are blocked and for some reason cannot use alternate static, how could you get a reliable static pressure reading? |
Break the glass of a pressure instrument |
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What is different about a sensitive altimeter? To what altitude does a typical altimeter work properly? |
It has a bank of android capsules instead of just one like the simple altimeter. This gives it greater sensitivity for small pressure changes. 35,000ft |
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What is a servo altimeter? |
It is electrically driven from signals from the air data computer. They’re more accurate at all altitudes and have less lag than conventional |
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Define the following: Height Elevation MSL Altitude |
Height, vertical distance between two things measured from a datum Elevation - vertical distance between something that is attached to the earth and the MSL MSL - the average sea level for a particular geographical location measured be experts Altitude - the vertical distance of something measured from MSL |
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Define following: Absolute altitude True altitude Pressure altitude Flight levels Density altitude |
Absolute alt- height of an aircraft over the surface (earth) or terrain it is overflying True altitude - actual height of a/c AMSL,it’s indicated alt corrected for temp error Pressure altitude - height of a/c measured from standard ISA pressure of 1013.25 Flight levels - areas of constant atmospheric pressure relating to 1013.25 and seperate by pressure intervals Density altitude - pressure height corrected for variations in temp from ISA it’s a density expressed in terms of an altitude |
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What are the two kinds of altimeter errors? |
Errors due to installation/instrument And atmospheric conditions |
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What are the altimeter errors that are from instrument/installation? |
Instrument error : due to small capsule errors being greatly magnified it’s hard to remove all regularities. Error increases with height. Pressure error (aka position error) : due to actual static pressure not being accurately transmitted to the instrument. Error increases with aircraft speed, but just prior to Mach 1 the error margin drops back. Can be due to positioning of static ports or bow wave of air from aircrafts speed. To correct, each aircraft must be individually calibrated and error is applied to indicated altitude. Time lag: due to linkage and capsule response not being instantaneous. Lag amount proportional to rate of altitude change. It will under read on climb, over read on descent. Hysteresis Error: When the capsule is stressed it can become imperfect and elasticise. This error is difficult to predict. |
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What are the atmospheric errors that can exist in an Altimeter? |
Barometric error - pressure in Kollsman window not set right Temperature error - this error will arise at any time the OAT or temperature lapse rate differs from ISA. If it’s colder than ISA altimeter will overread, warmer than ISA then it will underread. |
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If flying from an area of low pressure to high pressure will my altimeter overread or underread? |
Underread |
High to low - look out below |
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What will altimeter indicate if static port becomes blocked? |
It will continue indicating the altitude at which the blockage occurred |
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How do I work out True altitude |
On inside of computer at ‘TRUE ALTITUDE’ area Set Oat of the aircraft at the level it’s currently at against pressure altitude. The directly outside of that read true altitude against calibrated altitude. If I need to work out height above a point then subtract my current calibrated altitude from the elevation of whatever it is. E.g airfield at 4000 and I’m at 6300 then calibrated altitude reading will be for 2300ft |
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How do I work out true altitude using a calculator? |
Allow 4% for every 10 degree change from ISA. If the temp is hotter than ISA, altimeter will underread and true altitude will be above indicated. When cold, altimeter over reads, true altitude is lower than indicated. Once again high to low look out below |
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When will an airspeed indicator indicate TAS? |
When at MSL conditions in the ISA |
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What is a Vmo needle? Why would it change? |
Max operating speed for current altitude. Changes depending on altitude because at high flight levels the speed restriction is based on a Mach number. The Mach number limit (Mmo) equates to lower IAS at high levels |
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