This was disclosed by the men's lawyer in Rome on Wednesday. The ruling was a blow for the army and raised fresh doubts about the effectiveness of Italy's military hardware.
The four pilots served in Iraq last year, but after flying just one mission they refused to take to the air again, saying their helicopters did not have adequate anti-missile protection.
Army top brass said the helicopters were safe and accused the pilots of being cowards. But the tribunal said on Wednesday that the men had no case to answer, indicating that their concerns were justified.
"We showed that they didn't act out of fear, but out of a spirit of professionalism, having demonstrated that there were technical failings with their aircraft," said defence lawyer Franco Coppi.
The pilots had complained that their helicopters were only equipped with manual anti-missile systems, rather than faster automatic protection devices.
Italy has sent the fourth largest
foreign troop contingent to Iraq
Wednesday's ruling came exactly one month after an Italian soldier was shot dead by anti-US fighters while he was flying in an open-sided helicopter on patrol over southern Iraq.
His death sparked fresh controversy over the aircraft being used in Iraq, with critics accusing the government of failing to send modern, attack helicopters because it wanted to portray the Iraq deployment as a peacekeeping mission.
The Defence Ministry had authorised the army to send four attack helicopters to Iraq later this week.
Italy has sent 3000 troops to southern Iraq - the fourth largest foreign contingent there after the US, British and South Korean forces.