New Airspace Revision – RMZ’s & TMZ’s


RMZ’s are the poor mans controlled airspace, you cannot be told what to do inside the RMZ but you have to tell them what you are doing via the RT. Recently, as Southend airport changed from a toy airport to a real one, a RMZ was set up around it until this was replaced by permanent Class D controlled airspace.

A RMZ is airspace of defined dimensions wherein the carriage and operation of suitable/appropriate radio equipment is mandatory

The requirement for communications within a RMZ is as follows :

• VFR flights operating in parts of Classes E, F or G airspace and IFR flights operating in parts of Classes F or G airspace designated as a RMZ by the competent authority , shall establish two-way communication before entering the dimensions of the RMZ and maintain continuous air-ground voice communication watch, as necessary, on the appropriate communication channel, unless in compliance with alternative provisions prescribed for that particular airspace by the Controlling Authority
. • Before entering a RMZ, an initial call containing the designation of the station being called, call sign, type of aircraft, position, level, the intentions of the flight and other information as prescribed by the competent authority, shall be made by pilots on the appropriate communication channel.

The first RMZ was set up temporarily for Blackpool, for just under a month, while its radar was being replaced

The zone extended substantially beyond the airfield’s ATZ, stretching over 25 nm from East to West; a map shows the boundaries []

Hawarden Airport has proposed the setting up a RMZ, here is some information about the proposal:

Why Does Hawarden need an RMZ?

Hawarden Airport is situated within Class G Airspace (THE OPEN FIR) where two way communication with Air Traffic Control is not mandatory providing aircraft remain outside of the Aerodrome Traffic Zone (ATZ).

For the whole track of an IFR approach to Runway 04 and for a significant part of an IFR approach to Runway 22, aircraft operate within Class G Airspace.

For both runways, aircraft departures are flown in Class G Airspace before entering Class A (Controlled Airspace).

The reason we are considering the establishment of an RMZ is quite simply SAFETY. Hawarden is routinely used by large and fast aircraft, whilst at the same time General Aviation (GA) traffic has increased in volume and variety. We have witnessed an increasing number of unknown aircraft operating, totally legally, in the local area. Unfortunately, controllers aren’t always able to find a safe way to route aircraft around the unknown traffic, quite simply because we don’t know their intentions, they can turn, climb or descend at any point and we don’t know when that will happen. Moreover, smaller aircraft such as home-builds, and microlight-sized aircraft do not always generate a good radar return and sometimes they do display on radar at all. If we know your intentions in advance, we will be able to vector traffic to ensure the safety of all, whilst minimising the disruption to all flights.

Some of the types we have operating at Hawarden are:

  • Airbus Beluga Super Transporter
  • Embraer 145
  • Embraer 135
  • BAe 125
  • BAe 146
  • Citation 750
  • Challenger 300
  • Challenger 600
  • Falcon 2000
  • Hawker Horizon
  • Sentinel
  • Jetstream 31
  • BAe Hawk

Would you want to be in close proximity with one of these aircraft?

As with many UK airports, Hawarden Airport is in the process of evolving and developing: Beluga movements will increase as Airbus are increasing production and wing delivery over the next few years; the next generation Airbus Beluga may well be based on a larger aircraft; existing airframes in the business domain are being replaced by larger aircraft; other companies operating on the airport such as Airbus Helicopters, Marshall Aerospace and Flintshire Flying School are all looking to maximise flying opportunities.

The RMZ of course has the benefit of helping to reduce delays for our IFR aircraft but more importantly, significantly enhance the level of safety for all aircraft.


A TMZ is defined, as a volume of airspace within which aircraft are required to have and operate secondary surveillance radar equipment. TMZs are notified within the UK AIP for the purpose of Air Navigation Order 2009 Schedule 5 in relationship to Articles 28(7) and 39(2).

Some wind farms produce primary radar clutter on Air Traffic Control (ATC) radar screens. This clutter can obscure primary returns from aircraft and can interfere with radar tracking resulting in erroneous radar returns. This in turn reduces ATC’s ability to observe primary-only aircraft and increases the risk of ATC not detecting a conflict between aircraft and hence is detrimental to safety assurance. Large numbers of turbines would also lead to saturation of the radar processing systems unless blanked.

Blanking the wind farm areas eradicates clutter on PSR but will also prevent detection and display of primary returns from aircraft in the areas. In order to mitigate this loss of surveillance capability a Transponder Mandatory Zones may be introduced over the areas which are blanked to ensure visibility to ATC (via secondary radar) of all aircraft operating over the wind farms.

The Heathrow CTR is a mandatory transponder zone as are the runway approach ends of the Stansted CTA. You will also see a TMZ out to sea around the windfarm that is approximately 20 miles south east of the Clacton VOR.

The Southern chart is becoming swamped with airspace restrictions which is why we are so lucky at Halfpenny Green to have some of the most beautiful unobstructed FIR to our west. Amazingly most of the local flying schools choose to send their students into areas massed with other aircraft and airspace restrictions in the other direction!

Tamworth to Rugby down the A5 or Leominster to Shrewsbury beside The Long Mynd and The Clee Hill? Bit of a no brainer really but there again I prefer to keep my students as safe as possible and as happy as possible!  Even without the view it’s bad practice to have students returning from the east into sun, especially in the late afternoon but perhaps these schools think it’s easier to spot other traffic flying into sun! Although as one student found out when your instructors send you on a qualifying cross country with heavy rain showers the sun becomes the least of your worries. Guess what direction most of our weather comes from in this country? Duty of care starts by applying a little common sense!


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