SANTIAGO, Philippines (AP) — A light plane crashed Sunday while on a cloud-seeding flight over farmlands that have been scorched by the intense summer heat in the northern Philippines, killing all four people on board, officials said.

The plane crashed at a cornfield in a remote mountain village in Bagabag town in Nueva Vizcaya province, killing a woman and three men on board, Bagabag police chief Chevalier Iringan said.

Capt. John Andrews, deputy chief of the Civil Aviation Authority of the Philippines, said an investigation was underway to determine the cause of the crash in mountainous Nueva Vizcaya, which is about 200 kilometers (124 miles) north of Manila.