Assuming a worst-case scenario:
A
Y-20A (
with Russian engines) is reported to have a
maximum payload of around
55 tons. Assuming
cargo payload weight from passenger suitcases, belongings, medical supplies etc taking up around
10 tons, that leaves around
45 tons of payload capacity for
passengers.
From the National Statistics Bureau of China, the average body weights of
Chinese males and
Chinese females are
~70 kilograms and
~60 kilograms respectively.
The most recently available information indicated that there are likely around
2500 Chinese nationals currently in Sudan, most of which are located within and around Khartoum. Assuming a
80% male and 20% female composition, the total weight of these Chinese nationals would be around 170000 kilograms, or
~170 tons.
Assuming the number of Chinese nationals is accurate:
170 tons of Chinese nationals /
45 tons of payload per Y-20A =
3.778 Y-20As required.
This means that the operation would require
at least 4x Y-20As SORTIES to completely evacuate all Chinese nationals currently in Sudan.
However,
2500 Chinese nationals /
4x Y-20A sorties =
625 passengers per plane.
It would be very cramped to fit 625 passengers on a Y-20A, so let's reduce that number to
500 passengers per Y-20A.
Therefore,
at least 5x Y-20A SORTIES are required to completely evacuate all Chinese nationals currently in Sudan.
On the other hand, carrying a full payload means that the Y-20A(s) wouldn't be able to fly very far, since the fuel carried onboard has to be significantly reduced in order to not exceed the maximum takeoff weight of the Y-20A(s). This would require the Y-20A(s) to conduct mid-air refueling once the evacuated Chinese nationals are onboard, in case the Y-20A(s) have to fly to allied airport/air base that are further away.
The classic example is the US C-17 evacuation from Kabul during the Fall of Kabul in August 2021.
View attachment 111454
The C-17s involved in the evacuation of Afghan civilians carried up to around 640-670 people per aircraft. It has been reported that the C-17s require refueling as soon as they lifted off from Kabul International Airport in order to be able to make their way to US bases on the Arabian Peninsula.
TL; DR - It would be good for China to send not just
at least two Y-20A strategic transport aircrafts to Djibouti and Sudan, but perhaps
at least one YY-20A aerial tanker too.