"No reply" from helicopter
Ng also said that the Republic of Singapore's Air Force (RSAF) had issued calls to the helicopter to keep clear of Singapore's airspace, but "there was no reply".
RSAF F-16 aircraft were then scrambled to investigate.
"After determining that our security was not compromised, the F-16 aircraft were stood down," Ng said.
https://mothership.sg/2021/10/mha-concern-malaysia-helicopter-unauthorised-entry/