Boeing 737 HELIOS Crash Scene in Greece

Technova · #1 ● 01-21-2012, 03:24 PM

On August 14, 2005, a major aviation disaster occurred when Helios Airways Flight 522, a Boeing 737-300, crashed into a mountain north of Athens, Greece. All 121 passengers and crew aboard the flight, which was en route from Larnaca, Cyprus, to Prague via Athens, perished in the crash. This incident marked the deadliest aviation accident in Greek history and one of the worst involving a Boeing 737.

The tragedy unfolded after the aircraft lost cabin pressure shortly after takeoff. The loss of pressure led to hypoxia, incapacitating both the passengers and the crew. Investigators later revealed that the pressurization system had been left in the manual mode, a critical oversight that prevented the system from operating automatically.

As the aircraft flew on autopilot, it eventually ran out of fuel and crashed. Greek fighter jets had been scrambled to intercept the unresponsive Boeing 737, and the pilots reported seeing oxygen masks deployed inside the plane and the co-pilot slumped over the controls.

The investigation into the crash of Helios Flight 522 highlighted significant issues in the airline's safety culture and procedures. It brought attention to the importance of crew training and the need for rigorous safety checks. The Helios Airways tragedy led to reforms in aviation safety protocols, particularly in the areas of cabin pressurization and crew response to emergency situations.

DIRECT CAUSES:
1. Non-recognition that the cabin pressurization mode selector was in the MAN (manual) position during the performance of the:
a) Preflight procedure;
b) Before Start checklist; and
c) After Takeoff checklist.
2. Non-identification of the warnings and the reasons for the activation of the warnings (cabin altitude warning horn, passenger oxygen masks deployment
indication, Master Caution), and continuation of the climb.
3. Incapacitation of the flight crew due to hypoxia, resulting in continuation of the flight via the flight management computer and the autopilot, depletion of
the fuel and engine flameout, and impact of the aircraft with the ground.

LATENT CAUSES
1. The Operator’s deficiencies in organization, quality management and safety culture, documented diachronically as findings in numerous audits.
2. The Regulatory Authority’s diachronic inadequate execution of its oversight responsibilities to ensure the safety of operations of the airlines under its
supervision and its inadequate responses to findings of deficiencies documented in numerous audits.
3. Inadequate application of Crew Resource Management (CRM) principles by the flight crew.
4. Ineffectiveness and inadequacy of measures taken by the manufacturer in response to previous pressurization incidents in the particular type of aircraft,
both with regard to modifications to aircraft systems as well as to guidance to the crews.

CONTRIBUTING FACTORS TO THE ACCIDENT:
1. Omission of returning the pressurization mode selector to AUTO after un-scheduled maintenance on the aircraft.
2. Lack of specific procedures (on an international basis) for cabin crew procedures to address the situation of loss of pressurization, passenger oxygen
masks deployment, and continuation of the aircraft ascent (climb).
3. Ineffectiveness of international aviation authorities to enforce implementation of corrective action plans after relevant audits.