King Charles is set to attend the 80th Anniversary celebration of Mission Aviation Fellowship (MAF) at RAF Northolt on Thursday.
His Majesty will unveil the charity's new Cessna 208 Caravan aircraft during the event.
The new aircraft will be used to deliver aid to remote regions in Papua New Guinea.
The King will be greeted by RAF Northolt's Station Commander, Group Captain Jonathan Hough, before meeting MAF CEO Donovan Palmer.
King Charles is set to attend the 80th Anniversary celebration of Mission Aviation Fellowship (MAF) at RAF Northolt on Thursday.
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The event will also mark Papua New Guinea's 50th Anniversary of Independence.
His Majesty will meet members of the UK's Papua New Guinean community during the celebration.
The High Commissioner of PNG, Her Excellency Betty Palaso, will present the King to community members.
Among those attending will be Papua New Guinean Rugby League players representing Castleford Tigers in the Super League, including Judah Rimbu, Liam Horne, Sylvester Namo and Jeremiah Simbiken.
Mission Aviation Fellowship was founded at the end of the Second World War by RAF officers who wanted to use their wartime flight skills for peaceful purposes.
His Majesty will meet members of the UK's Papua New Guinean community during the celebration.
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Today, MAF is believed to be the world's largest humanitarian air operator. The charity operates a fleet of 117 light aircraft in more than 25 low-income countries.
These include Commonwealth nations such as Papua New Guinea, Kenya, Lesotho, Mozambique, Tanzania, Uganda, and Arnhem Land in Australia.
MAF flights deliver vital support including access to medicine, technology and education to isolated communities.
MAF began operating in Papua New Guinea in 1951, where the isolation and diversity of the country presents ideal conditions for the charity's mission.
With over 800 indigenous languages spoken in PNG, the region faces unique logistical challenges.
During the ceremony, His Majesty will unveil the new aircraft by opening the hangar door.
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During the ceremony, His Majesty will unveil the new aircraft by opening the hangar door.
The Cessna will be positioned next to a 1930s de Havilland Dragon Rapide bi-plane.
This historic aircraft is the same model used by MAF to establish flight operations in Sudan in 1950.
In those early days, missions were often conducted across uncharted territories with little more than a map and compass.
MAF works in partnership with governments and organisations to deliver food, building equipment and teachers, while also conducting medical evacuations.