Crossing the continent of Africa

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✈️ Flight Highlights

• Crossing the ITCZ (inter-tropical convergence zone)
• Limited communication system infrastructure in Africa
• Sahara
  

🌩️ Crossing the ITCZ

The ITCZ is a belt of low pressure which circles the earth around the equator, where the trade winds of the Northern and Southern hemisphere come together.

The ITCZ is a high-energy area characterized by a lot of convective (vertical movement of air masses) activity which produce vigorous thunderstorms and cumulonimbus (Cb) clouds. These areas are characterized by icing, turbulence, lightning and wind shear and can reach tops of altitudes that exceed the cruising altitude of the 777. They are often isolated in nature and this means we simply fly around them, resulting in impressive views.

The Cb you can see in the picture has a lenticular cloud above it called a Pileus (from the latin: cap) cloud. This cap is formed by the Cb that pushes the air above it upwards in a smooth fashion, so that it cools and condensates. These Pileus clouds are often temporary in nature as the Cb below will catch-up to it.

📡 Communicating in Africa

Communicating in Africa is interesting since in many FIRs (Flight Information Regions) communication systems have either not been implemented or operate below the required reliability. Sometimes VHF communications are difficult to establish or stations seem to be unmanned altogether. It can take a couple of tries before establishing voice communications. CPDLC is not yet implemented everywhere in Africa, although across a large portion of it. It can thus happen that you lose voice communication while not under CPDLC coverage. See the maps for reference.

To mitigate this risk we do an IFBP (In-Flight Broadcast Procedure). Basically this is an inter-pilot frequency (126.900) where you periodically call to all stations your position, altitude and intentions, and monitor for any conflicting information. There usually isn’t a lot of traffic over Africa so the frequency is not very congested.

🏜️ Sahara

I thought it was quite interesting to see nothing but sand for hours and hours. It contrasts nicely with the KLM blue.

I hope you enjoyed.

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