Questions are swirling about how passengers managed to access the cockpit and halt the apparent attempted hijacking of the Flydubai flight on Wednesday.

The alleged assailant, one of the pilots, stabbed his colleague in the cockpit as the plane plummeted – until passengers managed to subdue and restrain him, and stabilize the plane.

Israel has said that the wounded Captain Smit Machchhar unlocked the cockpit from the inside during the attack.

“Despite being severely injured, he managed to unlock the cockpit door – allowing Israeli passengers and the Emirati crew to intervene and save all the passengers,” wrote Israel’s foreign ministry in a post on X.

Josh McConkey, a US Air Force Reserve Colonel and emergency physician, said the aviation industry overhauled its security measures and protocols after the 9/11 attacks – including reinforcing the cockpit door to prevent potential hijackings.

“Unless someone is able to open that from the inside, you are not getting in,” said McConkey, who is also running for lieutenant governor of North Carolina.

“That’s one of the things that makes this so extraordinary, between the pilot himself, after being stabbed near death, bleeding profusely, is able to reach back and unlock that door, and then a random individual runs in and pulls up out of a dive that steep. It’s a miracle,” he said.

After 9/11, US airlines were required to install permanent reinforcements to all existing cockpit doors, and include them in newly-built aircraft. Many airlines and manufacturers opted to use bulletproof material, composites, reinforced door jambs and locks. The International Civil Aviation Organization, a UN agency overseeing global aviation, has a similar code of standards followed by member nations.

Investigators probing the Flydubai incident will likely explore the flight data recorder and cockpit voice recorder first, said Marco Chan, a senior lecturer in aviation operations at London’s Kingston University. They will also interview the crew, the off-duty pilots and passengers, and determine, among other pressing questions, how the cockpit door was opened.