Time can be expressed in several ways

Time can be expressed in several ways

Time can be expressed in several ways: as the time of day (0815, 1400, etc.) or elapsed time. Elapsed time is written as hours and minutes or minutes and seconds. With elapsed time, the units are separated with a “+” sign (2+30, 3+15, etc.). It may also be expressed in a six digit format such as 09+15+20.

Estimated time of departure (ETD) and estimated time of arrival (ETA) can be expressed in four-digit time of day format, while elapsed time, such as estimated time en route (ETE), will be expressed in hours and minutes (or for short distances, minutes and seconds). All aircrew must be able to convert from local time to Greenwich Mean Time (Zulu time) and vice versa. This will be covered in greater detail in Lesson Topic 6.2.

Speed is the magnitude of the velocity of an aircraft. It is the distance traveled with respect to time and is stated in nautical miles per hour (knots). Lesson Topics 6.3 and 6.4 will cover speed in greater detail and explain how atmospheric conditions (altitude, temperature) affect it.

Speed = Distance Time

METHOD OF NAVIGATION

There are three method of navigation currently used.

• Navigation by pilotage (visual landmarks)

• Dead reckoning navigation

• Radio Navigation

• Celestials or astronomical navigation

PILOTAGE

Pilotage or Piloting is the most common method of air navigation. This method, the pilot keeps on course by following a series of landmarks on the ground. Usually before take-off, pilot will be making pre-flight planning; the pilot will draw a line on the aeronautical map to indicate the desired course. Pilot will knows various landmarks, such as highways, railroad tracks, rivers, bridges. As the pilot flies over each of landmark, pilot will check it off on the chart or map. If the plane does not pass directly over the landmark, the pilot will know that he has to correct the course.

Navigation fix aircraft position on map by observing non visible land marks. Using compass, the direction to next land mark or destination. Electronic pilotage is also use with the aid of air bone radar. This is called electronic pilotage. The micro search radar provided with a PPD (Plan Position Display) mapped to terrain is used for electronic pilotage.

Pilots have various navigation aids that help them takeoff, fly, and land safely. One of the most important aids is a series of air route traffic control, operated throughout the world. Most of the traffic control uses a radar screen to make sure all the planes in its vicinity are flying in their assigned airways. Airliners carry a special type of radar receiver and transmitter called a transponder. It receives a radar signal from control center and immediately bounces it back. When the signal got to the ground, it makes the plane show up on the radar screen.

Pilots have special methods for navigating across oceans. Three commonly used methods are:

Inertial Guidance; this system has computer and other special devices that tell pilots where are the plane located.

LORAN Long Range Navigation The plane has equipment for receiving special radio signals sent out continuous from transmitter stations. The signals will indicate the plane location

GPS Global Positioning System. is the only system today able to show your exact position on the earth anytime, anywhere, and any weather? The system receiver on the aircraft will receives the signals from satellites around the globe

Advantage:

• Range is high (50 to 100 km)

• Accurate

If the ground is visible the navigator can see the principal features on the ground such as rivers, coastline, estuaries, rills etc. and fix his position. Even at night, the light beacons provide information about the position of the aircraft.