https://en.wikipedia.org/wiki/Attacks_on_parachutists
"
Attacks on parachutists, in term of the
law of war, is when
pilots,
aircrews, and/or
passengers are attacked while descending by
parachutes from disabled
aircraft during a
war. This practice is considered by most militaries around the world to be inhumane, barbaric, and unchivalrous, that it is unnecessary killing (i.e., they would eventually become
prisoners of war if
parachuted over enemy territory), that it is contrary to fair play, and that military pilots have to be held to a higher standard. Attacking people parachuting from an aircraft in distress is a
war crime under
Protocol I in addition to the
1949 Geneva Conventions. However, it is not prohibited under this Protocol to open fire on
airborne troopswho are descending by parachutes, even if their aircraft is in distress.
[1]"