How does an altimeter work and which errors can an altimeter experience?
How does an altimeter work and which errors can an altimeter experience?
When an aircraft climbs, the static pressure in the instrument case decreases, which allows the enclosed capsule to expand.
This in turn moves the needle on the instrument to indicate a corresponding altitude.
During descent, the opposite function applies.
Altimeter errors can originate and vary from:
Instrument Pressure Time-lag Barometric Density Temperature Blocked static port
What is induced drag?
What is induced drag?
Induced drag and its wing tip vortices are a direct consequence of the creation of lift by the wing.
Since the Coefficient of Lift is large when the Angle of Attack is large, induced drag is inversely proportional to the square of the speed whereas all other drag is directly proportional to the square of the speed.
The effect of this is that induced drag is relatively unimportant at high speed in the cruise and descent where it probably represents less than 10% of total drag. In the climb, it is more important representing at least 20% of total drag. At slow speeds just after take off and in the initial climb, it is of maximum importance and may produce as much as 70% of total drag.
Finally, when looking at the potential strength of wing tip vortices, all this theory on induced drag must be moderated by the effect of aircraft weight. Induced drag will always increase with aircraft weight.
If you are outside the range of any VOR’s/NDB's, how does the aircraft know where it is?
If you are outside the range of any VOR’s/NDB's, how does the aircraft know where it is?
Via INS/IRS/GPS
How do you get out of a spiral dive on a Cessna?
How do you get out of a spiral dive on a Cessna?
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Unload. Make sure you are no longer 'pulling G's'
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Roll wings level
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Power Reduce the power to avoid overspeeding.
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gently pull back on the control wheel to ease out of the dive.
When slowed down to a safe airspeed apply throttle as needed.
(N.b.: Do not confuse a spiral dive with a spin)
How can you calculate Vref?
How can you calculate Vref?
Vref = 1.3 x Vs0 (stall speed in the landing configuration).
What is DOM?
What is DOM?
The Dry Operating Mass (DOM) is the Basic Empty Mass and the Variable Load, also called the Aircraft Prepared for Service (APS) weight.
What does a bypass ratio of 11:1 mean?
What does a bypass ratio of 11:1 mean?
For every 1kg of air passing through the combustion chamber, 11kg of air pass bypass the combustion chamber.
What is the range of a VOR?
What is the range of a VOR?
VOR stations are fairly short range: the signals are line of sight between transmitter and receiver and are useful for up to 200 miles.
Each station broadcasts a VHF radio composite signal including the navigation signal, station's identifier and voice, if so equipped.
What can you tell about adiabatic lapse rates?
What can you tell about adiabatic lapse rates?
When considering a volume of air, adiabatic lapse rate is the temperature change that is caused by the vertical movement of the volume, andThe Lapse Rate is the rate at which temperature changes with height in the atmosphere.
The Environmental Lapse Rate (ELR) is according to ISA 2°C per 1000 feet increasing altitude.
For unsaturated air, the lapse rate is 3°C per 1000 feet, this is called the Dry Adiabatic Lapse Rate (DALR).
The Saturated Adiabatic Lapse Rate (SALR) is the rate at which saturated air cools with height and is, at low levels and latitudes, 1.8°C per 1000 feet.
If you are at the locator, on glide-scope, on localiser, but your altimeter is reading 500ft high what could be the cause of this?
If you are at the locator, on glide-scope, on localiser, but your altimeter is reading 500ft high what could be the cause of this?
False glide slope.