Latest tweets: Russian pilots shot dead as they descended in parachutes, by 10th Brigade of Syrian Turkmen who fight with the US-backed Free Syrian Army rebel group.
https://en.wikipedia.org/wiki/Protocol_I
“Article 42 outlaws attacks on pilots and aircrews who are parachuting from an aircraft in distress. Once they landed in territory controlled by an adverse party, they must be given an opportunity to surrender before being attacked unless it is apparent that they are engaging in a hostile act or attempting to escape. Airborne troops who are parachuting from an aircraft, whether in distress or not, are not given the protection afforded by this Article and, therefore, may be attacked during their descent.”
Turkey has not signed on to this agreement.