Authorities in the United Arab Emirates say a Flydubai co-pilot attacked the captain with an emergency crash axe and tried to take control of the aircraft during a flight from Dubai to Tel Aviv.
The incident happened Wednesday aboard Flydubai Flight FZ1073. The aircraft was eventually diverted to Tabuk, Saudi Arabia, where it landed safely.
UAE Attorney-General Hamad Saif Al Shamsi said Saturday that investigators had determined the co-pilot began carrying out what authorities described as a planned terrorist act while the aircraft was in flight.
According to the UAE investigation, the co-pilot attacked Captain Smit Machchhar inside the cockpit using a crash axe kept aboard the aircraft for emergencies. He then attempted to seize the flight controls.
The attack caused a sudden crisis aboard the Boeing 737. Reports from passengers described the aircraft dropping sharply as the struggle continued inside the cockpit.
Despite being seriously injured, Machchhar managed to release the cockpit door. That allowed other people aboard the aircraft to enter and help stop the attack.
Passengers Yaniv Hayoun, Dr. Shota Musayev and Asaf Rajuan were among those reported to have helped restrain the co-pilot. Hayoun later described grabbing the attacker and pulling him away from the controls.
Other Flydubai pilots who were traveling aboard the aircraft then helped stabilize the plane. The aircraft was diverted to Tabuk rather than continuing to Tel Aviv.
Flydubai initially confirmed only that an incident had occurred in the flight deck and said the aircraft had landed safely with all passengers accounted for. The airline said it was cooperating with authorities.
More details emerged as Israeli, Saudi and UAE officials investigated the incident.
Israeli Prime Minister Benjamin Netanyahu praised Machchhar and the passengers and crew members who intervened. He said their actions prevented a potentially catastrophic loss of life.
The UAE government has now provided its clearest account of the attack. Prosecutors said the co-pilot deliberately attacked the captain and attempted to take control of the aircraft.
Authorities are continuing to investigate the motive and whether anyone else was connected to the incident.
Reports have identified the co-pilot as Hamam al-Hammami, an Omani national. Associated Press and other news organizations reported that he had previously been barred from flying for Oman Air because of concerns about extremist views.
That information has raised questions about how he was later hired by Flydubai and what background checks were performed before he was allowed to fly for the airline.
Investigators are also examining physical and digital evidence to determine whether the attack involved outside planning or connections to other individuals or organizations.
The UAE has not announced that any militant organization was involved.
The incident has also raised questions about airline security because the weapon used in the attack was apparently already inside the cockpit. Crash axes are emergency tools carried aboard some aircraft and can be used to break through panels or other material during an emergency.
Because both pilots normally have access to cockpit equipment, the incident presents a different security problem from a passenger attempting to bring a weapon aboard an aircraft.
The aircraft was registered in the UAE, giving Emirati judicial authorities jurisdiction over crimes committed aboard the plane even though it eventually landed in Saudi Arabia.
Saudi authorities initially handled the aircraft and those involved after the emergency landing. The investigation was later transferred to UAE authorities.
Flydubai has suspended flights to and from Israel while authorities investigate the incident.
The airline has urged people to avoid speculation until investigators establish the full facts.
UAE prosecutors said technical examinations and reviews of physical and digital evidence remain underway. Authorities said final findings will be released after the investigation is completed.