Russian airstrikes on Kharkiv reveal rare but faulty bombs

At the end of June, the Russians attacked targets in Kharkiv using rare FAB-500T bombs, which did not explode. We explain how this variant differs from standard FAB family aerial bombs.

In the airstrikes on Kharkiv in the last week of June 2024, the Russians used unique FAB-500T bombs designed specifically for dropping from MiG-25 aircraft during high-speed flight.

According to the Defence Express portal, two bombs equipped with UMPK modules did not explode. These could be refurbished old bombs from the 1960s/70s or new production models. Regardless of their origin, their fuse was defective, which is common in new Russian weapons.

FAB-500T bombs are a special variant of the FAB-500 bomb, whose design was dictated by the objective to reduce aerodynamic drag as much as possible and increase resistance to the high temperatures resulting from air friction. The T variant was intended to withstand the temperature conditions at Mach 2.4 (about 1,864 mph or 3,000 km/h) and survive the g-forces during high-speed drops.

As a result, the bomb flew along a ballistic path rather than just falling, resulting in a range of 30-40 kilometres. Additionally, using the same high-speed drop tactic and equipping the bombs with a UMPK (Unified Planning and Correction Module) containing retractable wings, the flight range could be doubled due to gliding. With its satellite and inertial navigation systems, the module theoretically allows the bomb to hit its target with an accuracy of a few to a few dozen metres.

FAB-500T bombs contain around 260 kilograms of TNT, slightly less than the 300 kilograms for regular FABs. However, this does not make much difference because an aerial bomb is dozens of times more destructive than an artillery shell containing at most 10 kilograms of TNT for a 155 mm calibre.

Furthermore, adapting the bombs for high-speed drops significantly increases the chances of Russian pilots performing evasive manoeuvres in case of Ukrainian fire. This happens because a plane carrying standard FAB bombs must fly at a lower speed and cannot perform full-range manoeuvres due to, among other things, the G-forces.