Radio Glitch Triggers False Hijack Alert for Corendon Flight in Germany

German authorities briefly closed an airport and scrambled fighter jets to escort a passenger plane on Tuesday after receiving an emergency alert about a hijacking on board. The alert, however, turned out to have been triggered accidentally by a radio "glitch."

Corendon Airlines said its Boeing 737-800, en route from the Greek island of Corfu to Nuremberg, Germany, transmitted the emergency signal while flying over Croatia "due to a temporary fault in the radio communication system."

In a statement, the airline insisted that "no emergency situation occurred," and that the 178 passengers, the crew and the aircraft were never in danger at any point. The plane landed safely in Nuremberg.

What happened?

German police said Corendon Airlines flight XR456 "accidentally" transmitted the emergency "squawk" signal with the code 7500 while flying over Croatia on Tuesday.

A squawk is a four-digit code that pilots send via the aircraft's transponder to air traffic control. Code 7500 tells controllers that a hijacking is under way.

However, air traffic controllers were unable to reach the pilots or crew, making the alert appear even more serious. The reason for this remains unclear.

Police said: "The aircraft could no longer be reached by radio to clarify the situation," causing the alert to be activated in several European countries.

A Rafale fighter jet was dispatched from Croatia to intercept the passenger Boeing, while the German military also scrambled fighter jets.

Police cordoned off Albrecht Dürer Airport in Nuremberg as a precaution until they learned why the pilot had transmitted the hijack signal.

Police spokesman Michael Petzold explained that authorities "received a direct code from the cockpit indicating a possible hijacking."

Petzold said: "Because we were then unable to reach the cockpit, and the control tower also could not reach the cockpit, we had to assume the worst — that there really could be a hijacking."

The incident disrupted flights, with six delayed and two incoming flights diverted to other airports as a precaution, according to a Nuremberg airport spokesman.

Why are aviation authorities concerned?

The false hijack alert comes amid heightened aviation security concerns after the first officer on a Flydubai flight from Dubai to Israel attacked the captain with an emergency escape axe, forcing the flight to make an emergency landing in Saudi Arabia on September 30.

On Friday, the attorney general of the United Arab Emirates said the first officer was carrying out a "suicide" mission aimed at crashing the plane into Ben Gurion Airport in Tel Aviv, calling the incident a "terrorist attack."

In addition, before the false hijack alert in the early hours of Tuesday, flights had also been briefly disrupted at Nuremberg airport after a pilot reported a suspected drone sighting.

Authorities across Europe have stepped up surveillance of the skies in recent weeks after a series of largely mysterious drone incidents and concerns about Russian hybrid warfare.

Western countries, including Germany, accuse Moscow of waging a campaign of sabotage, espionage and disruption aimed at weakening European support for Ukraine and destabilising the continent.

Several German airports have had to briefly suspend operations in recent months due to drone activity, with suspicion often falling on Russia.

Last month, the German government accused Russia of carrying out a plot to attack Leipzig/Halle Airport in August using drones carrying explosives. Berlin closed a Russian consulate and took other measures.

Russian President Vladimir Putin rejected the accusations, saying Berlin "fabricated" the evidence. Amid these concerns, however, NATO's chief of general staff said at the Warsaw Security Forum earlier this week that the alliance has a new war plan to counter a Russian attack on members, incorporating lessons from the front line in Ukraine.

How common are radio faults and false hijack alerts?

Radio faults are fairly common, but such incidents rarely escalate into major security events because pilots use backup radios to communicate with air traffic control when they lose contact.

In 2019, a pilot flying an Air Europa plane from Amsterdam to Madrid accidentally transmitted the hijack alert code 7500. For half an hour, aviation authorities believed the alert was a genuine emergency and followed safety procedures, disrupting flights and forcing part of Schiphol Airport in the Netherlands to be evacuated.

In 2011, a flight from Chicago to Germany was diverted to Toronto when a pilot spilled coffee and accidentally triggered a hijack alert. The spilled coffee caused emergency signals to be transmitted, including transponder code 7500.