During tests of the Su-47 "Berkut" fighter, a failure of navigation instruments forced an emergency take-off of a Su-25 to escort and land the aircraft with an emergency fuel reserve. Hero of Russia, test pilot Sergey Bogdan, spoke about the situation.
According to him, after the instrument failure, the aircraft lost the ability to orient itself normally in space. An attempt to independently exit the clouds failed — their thickness reached almost three kilometers.
A Su-25 was urgently scrambled. I had an emergency fuel reserve left, as this aircraft has powerful engines with high fuel consumption. I managed to get behind the Su-25 and, despite the difference in speeds, stay with it in dense clouds.
Recall that the Su-47 "Berkut" was an experimental fighter with a forward-swept wing. It was never mass-produced; the aircraft served as a "flying laboratory" for developing Su-57 technologies.