Very High Frequency (VHF) Aircraft frequencies

Thursday June 16, 2011

AIR TRAFFIC CONTROL

Traffic management on the ground, in a "two dimensional" environment, can be very difficult at times. Picture the two dimensions as vehicles travelling at up to 110 kilometres per hour and able to vector themselves on two axis. Vehicles are all at the same level with a differentiation in speed and direction.

Now add a third dimension, vertical height. Now you have a traffic management environment where speed and direction variables now include a height variable. The maximum 110 kilometre per hour speeds can now be up to 10 times or more, meaning that the seperation between targets (aircraft) must now take into account vertical and horizontal seperation.

Such is the extraordinary skills required of an air traffic controller - to picture in their minds a three dimensional map of the airways projected on a two dimensional screen. Some air traffic controllers describe their job as a chess game where the pieces are cocoons with people in them travelling at very high speed.

In any case with increasing levels of air traffic the imaginary air "highways" are very well established. So too are the frequencies on which pilots communicate from the time of gaining an airways clearance to the time that they park the plane at their destination.

The number of air traffic frequencies in Australia are far too many to mention here, however to obtain frequencies for your local area have a look at the Aeronautical Information Package En Route Supplement Australia (ERSA).

Brisbane and Melbourne are the two primary air traffic control centres for Australia, however local airport frequency information is available in the ERSA specific to your nearest airport. Just find your local airport in the ERSA and click on the link.

GROUND TO AIR

If you live within a reasonable distance of Melbourne [Tullamarine] International Airport (YMML) or Melbourne Essendon (YMEN, and you have a reasonable antenna, you will hear air to ground traffic from commercial aircraft communicating with ground staff.

The transmissions from aircraft are short, sharp and to the point, usually relating to airline administrative information, such as ramp/gate numbers, fuel requirements, changeover crew/aircraft information and any special needs.

Try the following frequencies:

 

Frequency (MHz)
Company
119.525
QANTAS
129.500
QANTAS
130.000
Thai
130.850
QANTAS
130.925
Jetstar
131.150
Virgin
131.800
Malaysian
134.550
Tiger

You may have varying success with the ground stations, depending on your location, receiver and antenna.

I am using a simple VHF groundplane here, at around 4 metres in height with reasonable readability on these frequencies. Naturally if you can raise your antenna up higher, reception should be better. Aircraft can be heard for hundreds of miles but ground stations are naturally weaker.

AIR OPERATIONS

A number of frequencies have been allocated to specific air operations tasks.

Common frequencies, such as that used for search and rescue operations, provide a focal point for specific air operations and become well known.

Some of the more common allocations are highlighted in the following table.

Frequency (MHz)
Activity
119.1
Aero Club operations, flying school operations, fire spotting
119.2
Parachute operations

122.5, 122.7, 122.9

Gliders
122.8
Mustering, fishing, agricultural
123.45
Pilot-pilot air-air
126.4, 128.9, 135.55
Charter companies
129.9
Airport operators and refuelling
123.1, 123.2 and Marine FM 156.3, 156.8
Search and Rescue

Other allocated frequencies may be used less often, however it may be worth allocating a memory channel to them in your scanning receiver.

These include the air show frequency (127.9), crop dusting (129.6), avionics testing of communications equipment (129.1) and sports aviation activities (120.85).

In relation to air shows, by far the largest in the Melbourne Metropolitan area is the Avalon Air Show, held every two years.

The next show will be held in 2013 and it is worth noting that prior to the Avalon Air Show specific Avalon Airspace Procedures are published to advise of restricted zones and mandatory communications protocols, procedures and frequencies.

Such publications are extremely detailed and specific in terms of instructions. Here is an example of an air show AIP for the 2011 Avalon Air Show.