The Philippine Air Force is in mourning the death of two pilots after their trainer aircraft crashed during a flight training mission in the mountainous area of Tuba, Benguet.

The aircraft had taken off from Fernando Air Base in Lipa, Batangas and was en route to Baguio City when the incident happened, the Air Force said.

Authorities said the pilots were on a routine training flight when the aircraft went down. Both were found unconscious at the crash site and were rushed to a hospital but they passed away later.

The pilots’ remains were brought to the Villamor Air Base where Air Force officials coordinated with the families of the victims.

An investigation is ongoing to determine the cause of the crash.

Col. Ma. Christina Basco, Chief of the Philippine Air Force Public Affairs Office, said a safety investigation team has been deployed immediately.

“So, nung nangyari na po ‘yun, nag-deploy na po since yesterday po ‘yung ating Safety Investigation Board. Sila po ‘yung nag-a-analyze, ang nag-i-investigate doon sa nangyaring aksidente. Ngayon po, may team na po doon at naka-cordon na ‘yung area to ensure na agaran at hindi ma-tamper ‘yung mga aircraft parts doon,” Basco said.

The Air Force said the crash site has been secured to preserve evidence as part of the investigation.

No other details about the aircraft and identities of the pilots have been released, as of this writing.