Hi Brian, I suppose you know about this well known accident but as I am not visiting this thread so ofthen I have no idea if you know it or not:
On 28 June 1940, while landing on the Italian airfield of
Tobruk a few minutes after a British air attack, Balbo was shot down by Italian gunners and killed. The cruiser
San Giorgio started firing on his
Savoia-Marchetti SM.79 airplane (bearing the civil registration "I-MANU" in honor of his wife, Donna Manu),
[12] followed by the airport's anti-air guns. It is still not clear which of them shot him down.
http://en.wikipedia.org/wiki/Italo_Balbo
Pavel