Related Rule
Italy
Practice Relating to Rule 48. Attacks against Persons Parachuting from an Aircraft in Distress
Italy’s IHL Manual (1991) prohibits firing at the crew of an aircraft in distress. 
Italy, Manuale di diritto umanitario, Introduzione e Volume I, Usi e convenzioni di Guerra, SMD-G-014, Stato Maggiore della Difesa, I Reparto, Ufficio Addestramento e Regolamenti, Rome, 1991, Vol. I, § 8(3).
It adds that, in other cases, “it is lawful to open fire at enemy soldiers who … descend by parachute, isolated or in a group”. 
Italy, Manuale di diritto umanitario, Introduzione e Volume I, Usi e convenzioni di Guerra, SMD-G-014, Stato Maggiore della Difesa, I Reparto, Ufficio Addestramento e Regolamenti, Rome, 1991, Vol. I, § 10.
The manual also defines intentional homicide and mistreatment of persons parachuting in distress as a war crime. 
Italy, Manuale di diritto umanitario, Introduzione e Volume I, Usi e convenzioni di Guerra, SMD-G-014, Stato Maggiore della Difesa, I Reparto, Ufficio Addestramento e Regolamenti, Rome, 1991, Vol. I, § 84.
Italy’s LOAC Elementary Rules Manual (1991) states: “A combatant who is recognized (or should be recognized) as being out of combat may not be attacked (… descending by parachute in distress).” 
Italy, Regole elementari di diritto di guerra, SMD-G-012, Stato Maggiore della Difesa, I Reparto, Ufficio Addestramento e Regolamenti, Rome, 1991, § 72.
Italy’s Combatant’s Manual (1998) states:
IT IS NOT PERMITTED to open fire on a pilot/crewmember who has parachuted out of a plane that has been hit, or on a shipwrecked person from a ship that has been hit or sunk. Moreover, it is permissible to attack, apart from the above cases (airplane that has been hit/sunk), those combatants who are parachuting or who are using boats to conduct combat actions. 
Italy, Manuale del Combattente, SME 1000/A/2, Stato Maggiore Esercito/Reparto Impiego delle Forze, Ufficio Dottrina, Addestramento e Regolamenti, 1998, § 250.
[emphasis in original]
Italy’s Law of War Decree (1938), as amended in 1992, prohibits firing at the crew of an aircraft in distress. 
Italy, Law of War Decree, 1938, as amended in 1992, Article 35(3).
The Decree further provides that, in other cases, “it is lawful to open fire at enemy soldiers who … descend by parachute, isolated or in a group”. 
Italy, Law of War Decree, 1938, as amended in 1992, 1938, Article 38.