Two fighter jets were dispatched to investigate what was happening with Helios Flight 522.
“Helios 522, is anyone there?”
Desperate questions echoed repeatedly on the cockpit radar on a day in Greece, August 14, 2005. This was an aviation disaster unlike any other. The Boeing 737, carrying numerous passengers, was flying in circles for over an hour in autopilot mode. The plane was unmanned, the captain had disappeared, the first officer was slumped over, and all passengers were drifting into sleep.
What happened on Helios Airlines Flight 522?
“The Ghost Flight”
Helios Flight 522 was tasked with transporting 115 passengers from Cyprus to Václav Havel Airport Prague in the Czech Republic. The aircraft took off smoothly at 9:07 AM, only a few minutes late from its scheduled departure.
Both the captain and first officer were experienced pilots. The cabin crew included four members, among them the engaged couple Andreas Prodromou and Haris Charalambous.
Andreas had just completed his pilot training in the UK, intending to pursue his dream career and then marry his fiancée Haris. Unfortunately, neither of these dreams would come to fruition.
The crew on Helios Flight 522. (Photo: Simpleflying).
Minutes after takeoff, alarms began to sound. This was a signal for the crew to descend, but the captain dismissed it, misunderstanding it as a malfunction warning. In the following minutes, the captain’s communication with air traffic control dwindled.
At 9:20 AM, as the aircraft approached an altitude of 30,000 feet, there was no further communication from Flight 522. The Boeing continued to fly in circles over the Athens coastline in autopilot mode. Air traffic control attempted to reach the plane for 70 minutes, but no one responded. A hypothesis emerged that Flight 522 was being hijacked by terrorists.
The Athens rescue coordination center dispatched two fighter jets to investigate the Boeing circling the sky. (Illustration: Wikimedia Commons).
By 11:00 AM, the Athens rescue coordination center decided to take bold action. Two Greek Air Force fighter jets were launched to check the condition of the Boeing. From their windows, the fighter pilots observed a very strange scene.
All passengers on Flight 522 were slumped over, the captain was missing, and the first officer was motionless on the control panel. However, one man was still alert, walking in the passenger cabin; he walked straight into the cockpit and sat in the captain’s seat. He was flight attendant Andreas Prodromou, the only one still awake on the flight.
Unconscious on the Plane
Subsequent investigations revealed that at the time the aircraft lost contact with air traffic control, all passengers and crew had lost consciousness due to a lack of oxygen in the cockpit. The reason Andreas Prodromou remained conscious was due to his frequent diving practice, giving him a larger lung capacity than the average person, and he also understood how to use the oxygen supplies on the aircraft.
Andreas Prodromou accessed the cockpit using an emergency code, attempting to wake the pilots but was unsuccessful. Although he had a license for small aircraft, controlling a Boeing 737 was beyond his capabilities. It is believed he did his utmost to maneuver the plane away from populated areas to minimize casualties.
The Boeing crashed into a hill near Athens, and Andreas Prodromou attempted to steer the aircraft away from residential areas. (Photo: FAA).
In the final moments, as the aircraft was running low on fuel, the left engine ceased operation. The flight attendant continuously transmitted a Mayday emergency signal, but unfortunately, he had chosen the wrong frequency.
Andreas looked out the cockpit window at the two fighter jets. He pointed downward. The right engine of the aircraft had caught fire, and the plane was out of fuel. The Boeing 737 plunged straight down into a hill near Athens. All 115 passengers and six crew members perished. It is believed the passengers were still alive, only unconscious at the time of the crash.
The cause of the accident was determined to be that during maintenance of the aircraft, the ground engineer had switched the pressure control knob to manual mode and forgot to revert it back to automatic mode as usual.
The ground engineer selected manual pressure mode (MANUAL) instead of automatic pressure (AUTO). (Illustration: FAA)
Upon boarding, the pilots did not notice this. They mistakenly ignored the alarm indicating an error, causing the aircraft to remain unpressurized throughout the flight. Pressurization is a critical system; without it, the air inside would be too thin and lacking in oxygen, leading everyone to fall into a coma. Passengers seemingly were not informed to use oxygen masks in time.
The disaster from “Ghost Flight” 522 was attributed to a series of failures in maintenance, piloting, and air traffic control, when the air traffic controller was absent, leaving only the staff on duty that day. Helios Airways faced numerous lawsuits and declared bankruptcy in 2006, just one year after the accident.
This serves as a significant lesson for airlines in ensuring compliance with flight safety responsibility principles to avoid disasters like the story of Helios Airways.
