Originally Posted by Civil the Civillian
Shooting at a helpless man in a parachute is on par with an aircraft dropping a munition over a man with an AK47 ... both are helpless at fighting off their attacker.
The two actions are very different. One is an act of war (legitimate and/or legal under the appropriate circumstances), the other contravenes Article 42 of the Geneva Convention (Protocol I - important as I shall explain in a moment), which states, 'No person parachuting from an aircraft in distress shall be made the object of attack during his descent.'
All three nations are signatories to the Geneva Convention, but note that Russia and Syria ARE signatories to Protocol I whilst Turkey is NOT.
However, International Law of Armed Conflict also covers this in the 1868 St Petersburg Declaration, which allows for whatever reasonable force is necessary, lawful and operationally justified in combat to make your opponent submit. ILAC specifies that who are out of action, such as surrendering combatants,
air crew parachuting from downed aircraft, the wounded, sick and shipwrecked, prisoners of war and other captives and detainees, must be identified as such and treated humanely.
International Law of Armed Conflict applies to conflict between and within nations even when there has been no formal declaration of war.
I'm not sure if you are questioning the morality of air attack or trying to distinguish that from attacking military personnel who are hors de combat. To me the difference is clear, but I'll leave it at that for now.