The war relic, which was unearthed last week, had been deemed unsafe to move and hence had to be disposed of on-site by the military.
The emergency landing was reportedly due to severe weather conditions.
Djamani was the second person to be executed in Singapore this week over a drug offense, as 57-year-old Mohd Aziz bin Hussain had been executed a few days prior.
The tiny city-state of Singapore has a powerful military fist, not talked about but evident to hostile neighbors. And Israel played a crucial role in creating it.
Israeli Embassy in Singapore holds first public reception in three years for Israel Independence Day.