Zia was most likely killed by the Soviets. The best theory I’ve read - which also explains the plane’s unusual flight pattern - consistent with the pilots being unconscious - described a nerve agent being released in the cockpit once the flight reached a certain altitude.
Of course, it could have been just an accident, and we’ll never know (unless the KGB/Soviet files are ever truly opened).
But Zia was providing the bulwark of the support of Afghanistan rebels to the Soviet occupation next door. No one wanted him dead more than the communists.
Simon Foxx: I like your theory because it fits in with what was going on in those days.
However, we always can fall back on The Helen Thomas Theory which simply consists of “blaming everything on the Joosz”.
Helen is known in Hell as the “Devil’s Fart”.
Piss be upon her!
Really don’t need a nerve against. Just flip a switch or faulty breaker that fails to pressurize the cabin. The masks deploy automatically in the passenger compartments but are manually deployed in the cockpit.
The pilots could simply have become anoxic and that’s all she wrote.