What to know about the terrifying FlyDubai flight forced to land in Saudi Arabia

One pilot stabs another as he attempts to take control of a flight from the United Arab Emirates to Israel with the aim of crashing it, according to Israel's prime minister.

Passengers, many of whom are Israelis, fear for their lives as the FlyDubai aircraft loses half its altitude in about a minute.

As Israel scrambles fighter jets out of concern for a possible hijacking, a passenger and crew member break into the cockpit to subdue the attacker and other crew members gain control of the aircraft, which lands safely in Saudi Arabia.

The terrifying incident on Wednesday occurred just days before the anniversary of the Oct. 7, 2023, attack on Israel that launched the war in Gaza. It has rekindled anxieties about airline security and focused attention on an unsettling question: Are pilots a significant threat to the flying public's safety?

Here’s what we know — and don’t know — about what happened on FlyDubai flight FZ1073:

The distress call came at 8:44 a.m. local time, about two and a half hours after the flight with about 170 passengers left Dubai and headed to Tel Aviv.

The captain and first officer had been fighting in the cockpit after one tried to stab the other and crash the aircraft, according to Israeli Prime Minister Benjamin Netanyahu.

The aircraft swiftly lost altitude — dropping from 33,000 feet to 17,000 feet (around 10,000 meters to 5,100 meters) in the span of about a minute. It then circled close to the Jordanian border before landing in Tabuk, Saudi Arabia, about an hour later.

Both pilots suffered injuries that required hospital treatment, according to a statement from Tabuk's Prince Sultan bin Abdulaziz International Airport. Netanyahu said Saudi Arabia had arrested one of the pilots.

A plane carrying passengers from the flight landed Wednesday evening in Israel.

A passenger and a crew member managed to break into the cockpit, enabling other crew members to enter and fly the plane to a safe landing, according to Netanyahu, who cited a passenger he had spoken to.

The cockpit door on all aircraft is locked during flight for security reasons — a measure that became the industry standard after the Sept. 11, 2001 attacks, in which hijackers broke into the cockpits of four domestic flights in the United States.

It's unclear how the passenger and crew managed to get into the FlyDubai cockpit since aircraft doors are reinforced to withstand attempts to break them down.

One question surrounding this incident is how anyone on the aircraft — even a pilot — was able to get a knife onboard. It's unclear how big the knife was that was used in the attack.

Pilots undergo rigorous screening, including passing through metal detectors, at checkpoints at all airports. It's also standard for airlines to vet their pilots' background for criminal and employment history, their physical and mental health, as well as having them undergo intelligence and security screening.

Israel has some of the most stringent airline security measures worldwide. Passengers on Israel-bound flights regularly are taken aside for questioning and baggage searches after passing through normal airport security. It's uncertain whether the pilots of the FlyDubai flight had been screened as vigorously.

There have been extremely rare occasions when airline security protocols fail. In 2015, the co-pilot of Germanwings Flight 9525 locked the captain out of the cockpit and deliberately set the plane on a collision course with a mountainside, killing all 150 people aboard.