Engineering Level 4: Issued Flak Jacket
Only the most expert Engineers who have proven their ability to survive on the battlefield are issued with these expensive Flak Jackets which provides the player with 50% damage deflection from explosive weapons.
are we talking just grenades and rockets?
or does that intitle mines, air strikes, and artilary?
I thought it was any weapon that causes splash damage, after all it is a flak jacket, a bloody expensive one at that 
seems to be any weapon with splashdamage. as level 4 eng i was able to survive stepping directly on a mine and proceed to plant 4 dynamites in a row before axis oculd get to me 
Works great for protecting against arty also! I survived two “shells”. It was part of my own stupidity, I thought I could make it before the rain started, so I kept running. Got sent airborne, landed, ran forward again: airborne again, landed, and finally the third killed me.
They most likely were not direct hits, but the concussion from the splashdamage that sent me flying.