Civil Air Regulation

Flight rules

VFR ( visual flight rules) VMC Visibility 5 km or more Flight level <= F150 ————————— IFR (instrument flight rules) IMC visibility less than 5 km Any flight level as IFR flight is irrespective of weather.



Category , DECISION HEIGHT ( DH) ,RVR CAT I,60 Meters,Visibility not less than 800 m RVR not less than 550 m CAT II,60 to 30 Meters,350 m CAT IIIA,30 Meter or Less,Not less than 200m CAT IIIB,15 Meter or Less,RVR between 200m to 50m CAT IIIC,0,No RVR Limitation Blind Landing CATIIIC Read more…



Altimeter The altimeter shows the aircraft’s altitude above sea-level by measuring the difference between the pressure in a stack of aneroid capsules inside the altimeter and the atmospheric pressure obtained through the static system. It is adjustable for local barometric pressure which must be set correctly to obtain accurate altitude Read more…


Convergency & Conversion Angle

  Convergency : It is the inclination between two meridians at a given latitude. It is Maximum at poles and ‘0’ at equator  . It varies a function of SIN of mean latitude. Convergency = d.Longitude X Sin Mean latitude X = A2 – A1 Conversion Angle : Angular diffrence Read more…


1 by 60 rule

It can be used when Track Error is less then 20* Track Error= (Distance Off Track/Distance Flown)x 60 Question:  After flying for two hours at a ground speed of 240 kts an a/c pinpoints itself 12 NM off track. Find the Track Error? Answer:  Track Error = (12/240×2)x60 T.E.= 1.6*

Categories of aircraft


There are three major types of Directions, 1. Magnetic Direction : Its a direction in which freely suspended magnet unaffected by any Magnetic field points is called Magnetic North. Its not Geographical. 2.True Direction : Its a direction which is measured with respect to True North. 3.Compass Direction: Direction which compass Read more…



Departure  is rhumb line distance in NM (Nautical mile) in the East West direction of a given latitude for a given difference in longitudes.   Dep= d.long (in mins) x Cos Lat. x 6o Note: It is max at Equator & Zero At Poles. Function Varies as Cos of Latitude. Read more…


Rhumb Line

  In navigation, a rhumb line (or loxodrome) is a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the same bearing, without changing the direction as measured relative to true or magnetic north.


Great Circle

  A great circle, also known as an orthodrome or Riemannian circle, of a sphere is the intersection of the sphere and a plane which passes through the center point of the sphere.