Eight people including the pilot were on board the plane when it reportedly started to disintegrate halfway into its climb, at around seven thousand feet, forcing the passengers to jump for their lives.
Two people, both Portuguese aged 40 and 45, were left seriously injured after jumping, and two other people, women aged 37 and 48, sustained lighter injuries.
The remaining three skydivers did not need to be taken to hospital; the only fatality was the pilot.
Debris from the German-registered Pilatus P6 was scattered over a five-kilometre radius near the village of Canhestro, with parts including a wing, a door and the plane’s wheels having been located within the first few hours.
Two engineers from the Swiss manufacturer of the plane have been drafted in to help Portuguese investigators with an “exhaustive investigation” to discover the cause of the accident, working with the Portuguese Aviation Accidents Prevention and Investigation Department (GPIAA).
The 10-seater aircraft belonged to a private German operator that provides services for the Algarve-based airline Aero Vip, which operates the regional flights between Portimão and Bragança, Porto Santo and Funchal.
The 49-year-old aircraft had recently returned from an extensive maintenance intervention carried out in Spain between 20 May and 17 June.
Aero Vip belongs to the 7Air group, which also owns the Portimão-based skydiving company Skyfall.
Speaking to newspaper Diário de Notícias, the 7Air group said the plane had come back from Spain “with all its technical documentation approved.”
The company also praised the “professionalism and altruism of the Belgian pilot” who died in the crash, and whose actions they said “contributed towards there being no further deaths.”
The 27-year-old, who is said to have been a very experienced pilot with more than 2,000 flying hours under his belt, was reportedly found with his parachute on, but had not deployed it.
In a joint statement Skyfall and the 7Air Group said they are “fully committed to establishing the as yet unknown causes of the accident” and are collaborating with the relevant authorities as well as with the aircraft’s manufacturers.