Summary
SamenvattingCNS 3
- Course
- Institution
Samenvatting CNS. Aviation Studies
[Show more]
Seller
Follow
AllStuvia
Reviews received
Content preview
Summary CNS systemsWeek 1
Height:
Altitude in aviation can have several meanings, it needs to be modified (true altitude) or
implicitly communicated between different parties.
Aviation altitude is measured by using either MSL (Mean Sea Level) or AGL (Above
Ground Level) as a reference point. The altimeter is always set to standard pressure
when flying at a Flight level: 1013.25HPa. In the cockpit the definitive instrument for
measuring altitude is the pressure altimeter, which is an aneroid barometer with a front
face indicating distance instead of atmospheric pressure.
The different types of aviation altitude:
Indicated Altitude: Reading on the altimeter when the barometric is at MSL
Absolute Altitude: Height of the aircraft above the terrain it’s flying
True Altitude: Actual elevation above MSL.
Height: The elevation above a ground reference point.
Pressure Altitude: The elevation above a standard datum air-pressure plane.
Density Altitude: The altitude corrected for non-ISA atmospheric conditions.
QNH is the barometric altimeter setting that causes an altimeter to read airfield
elevation above mean sea level when on the airfield. In ISA temperature conditions the
altimeter will read altitude above mean sea level in the vicinity of the airfield.
QFE is a barometric altimeter setting that causes an altimeter to read zero when the at
the reference datum of a particular airfield.
The altitude has to be corrected for the temperatures that differ from ISA alt that altidue
is 4ft/ C. / 1000ft.
RA stands for radio altimeter, it measures the altitude above the terrain presently
beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to
reflect from the ground and return to the plane. This altimeter provides the distance
between the antenna and the ground directly below it. Since speed, distance and time
are all related to each other the distance from the surface providing the reflection can
also calculate the speed by making use of the speed of light.
,Distance:
A nautical mile is defined as an arc along a meridian of the Earth. Making a meridian
180*60 = 10.800 nautical miles.
The length of nautical miles differs from the length-based standard in that a minute of
arc, the length equals about 1.861 meters at the poles and 1.843 meters at the equator.
The derived unit of speed from the nautical mile is the knot. One knot is equal to one
nautical mile per hour.
Great Circle Distance:
The great-circle (orthodromic) distance is the shortest distance between two points on
the surface of a sphere, measured along the surface of the sphere. Through any two
points on a sphere which are not directly opposite each other, there is a unique great
circle. The two points separate the great circle into two arcs. The length of the shorter
arc is the great-circle distance between the points. The distance between two points,
which are directly opposite each other, are called antipodel points.
The distance can be calculated by:
Where as the latitude = ϕ and the longitude = λ . The radius of the sphere is equal
to = 6371km = 3440nm. The angels in this formula are noted in radials.
, Heading Track:
Directions are measured clockwise from north, either true or magnetic, in degrees from
0 to 360, following compass convention (0=N, 90=E etc.).
In the figure above the relationship between true and magnetic direction is seen.
With:
1. True north
2. Heading
3. Magnetic north
4. Compass north
5. Magnetic deviation
6. Magnetic variation
7. Compass heading
8. Magnetic heading
An aircraft’s heading is the direction that the aircraft’s
nose is pointing towards. It is referenced by using either
the magnetic compass or heading indicator. The most
used heading tool in smaller aircraft is the magnetic
compass, although it has its errors. Such as variation: the
difference between true and magnetic directions.
Deviation: caused by vessels in the magnetic field.
Geographic latitude and longitude
The “latitude” of a point on the earth’s surface is the angle between the equatorial plane
and the straight line that passes through that point and through the center of the earth.
The North Pole is 90 N; South Pole 90 S and the equator is 0. The equator divides the
globe into Northern and Southern Hemispheres. The “longitude” of a point on the earth’s
surface is the angle east or west from a reference meridian to another meridian that
passes through that point. The combination of these two components specifies the
position of any location on the surface of the earth (without consideration of altitude).
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller AllStuvia. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.34. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79079 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now