What happened
On 4 October 2014, an Emirates Airbus A330-243, registration A6-EAQ, was preparing for departure from Karachi International Airport, Pakistan. During the pre-departure phase, the flight crew noticed a distinct odor in the cabin and cockpit, alongside a low-pressure indication for the yellow hydraulic system on the ECAM.
As the mist spread, it caused respiratory discomfort and eye irritation for the 82 people on board. In an attempt to manage the perceived smoke, a cabin crewmember attempted to use protective breathing equipment (PBE). However, upon activating the oxygen generator, the PBE caught fire, creating a localized flame that crewmembers had to suppress. Due to rapidly declining visibility in the cabin, the commander ordered an emergency evacuation while the aircraft was at its final pushback position.
The investigation
The GCAA AAIS investigation focused on the origin of the airborne mist and the failure of the emergency equipment. Investigators traced the mist back to a fractured hydraulic hose that supplies the rudder yellow system actuator. The leaking fluid had entered the auxiliary power unit (APU), where it was heated and atomized before being distributed through the aircraft's air conditioning system.
Findings
- The primary cause of the mist was a failure of a yellow hydraulic system rudder servo hose, likely due to fatigue failure of the metal braiding and subsequent fracture of the PTFE core.
- The activation of the PBE resulted in a fire, which was likely caused by manufacturing defects in the PBE oxygen-generating candle.
- The flight crew continued to run the APU during the initial phase of the incident because they could not identify the source of the mist, which could have potentially exacerbated the situation.
- During the evacuation, passengers were left near the aircraft without clear direction, and airside traffic continued to move through the area without interruption from air traffic control.
Safety action
Following the incident, Emirates replaced the problematic PBE units with a new gaseous system to avoid oxygen-candle ignition risks. The airline also replaced the subject hydraulic hoses across its fleet. The GCAA AAIS issued several recommendations to the airline, Airbus, and the Karachi Airport Authority regarding improved evacuation procedures, passenger management, and the refinement of smoke/fumes checklists.