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Johannesburg Special Rules and QNH
Are you on the correct QNH setting?

QNH is used to ensure safe terrain separation when cruising at lower altitudes.  It is the Barometric pressure set on you altimeter.


For safety reasons, everyone should be on the same QNH when flying in a Special Rules Area.  If you are not on the FAOR QNH when flying in the JHB Special Rules Area, you can very easily, unintentionally, infringe on the JHB TMA that starts at 7600ft. 

When flying within the Johannesburg Special Rules Area, your altimeter must be set on the the current FAOR QNH. 

How do you know what the QNH is for the Jhb Special Rules area?

1. Find out via the current METAR available for FAOR
2. Phone or call ATC
3. or listen to ATIS FAOR on radio frequency 126.2 for QNH information as soon as you are airborne 

Remember, if your track is between 270° and 089° (northerly direction), your altitude should be 7500ft, and on a track between 090° and 269° (southerly direction), your altitude should be 7000ft.  If you are unable to comply with this, then you should fly at 6500ft or below.  These tracks are all flown on the FAOR QNH.  

These requirements are published in the AIP ENR 1.3.2 

Suggested position reporting to include the following:
Registration, Route, VFR reporting point, direction, altitude (on Tambo QNH)
eg: ABC passing overhead Sandton City, North Bound, at 7500ft on Tambo QNH 1021

 
What is QNH?
"QNH - The altimeter sub-scale setting that will make the altimeter read airfield elevation when on the ground at the airfield." - Jim Davis

As taken directly from Wikipedia:

QNH is a Q code indicating the atmospheric pressure adjusted to sea level. It is a pressure setting used by pilotsair traffic control (ATC), and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to read altitude above mean sea level within a certain defined region. Within United Kingdom airspace, these are known as Altimeter Setting Regions (ASRs); these regions may be large areas, or apply only to the airfield for which the QNH was given. An airfield QNH will cause the altimeter to show airfield altitude, that is, the altitude of the centre point of the main runway above sea level on landing, irrespective of the temperature.

In the United Kingdom the lowest forecast value of QNH for an altimeter setting region is called the "Regional Pressure Setting" and may be used to ensure safe terrain separation when cruising at lower altitudes. In some parts of the world a similar procedure is adopted and this is known as "Regional QNH" however this name has been modified to the above in the UK to avoid ambiguity.

What is the Special Rules Area?

“The area of protected airspace where special – non-standard – rules are applied to promote safety efficiency and orderliness within a congested airspace.”

In South Africa we have various Special Rules Areas with VFR routings around or into busy airspaces. The pilot should familiarize himself with Rules and Frequencies before flying into these Areas. (EasyPlan and EasyCockpit have all these airspaces covered)

When flying within the special rules area, the following is recommended:

  • Use published VFR Routings and reporting points
  • Keep landing lights on
  • Squawk 2000 with ALT (Mode C)
  • Helicopter Squawk 2600
  • At max IAS 180 kts
For any additional information or tips, please don't hesitate to contact us.

The Aviation Direct Team
Andrea, Glynn, Mandy, Alexis, Sean & Stephen
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