What happened
On 8 November 2013, a Ryanair Boeing 737-800, registration EI-DPF, was performing a scheduled international flight from Tangiers Airport, Morocco, to Niederrhein Airport, Germany. Shortly after takeoff, while climbing through approximately 8,500 feet, the flight crew received an emergency call from the cabin crew reporting smoke appearing above the overhead compartments in the passenger cabin.
The flight crew immediately halted the climb, stabilized the aircraft at 11,000 feet, and declared an emergency. The aircraft diverted to Seville Airport, Spain, arriving approximately 23 minutes after the initial report. Upon landing, the captain stopped the aircraft on an exit taxiway to allow for an inspection by firefighters. Although no fire or heat source was detected, the captain elected to disembark the 175 passengers and 6 crew members via the taxiway as a precaution. No injuries were reported.
The investigation
The CIAIAC investigation focused on the source of the smoke and the cabin environment. Investigators examined the aircraft's air distribution system and found that three flex hoses connecting the sidewall riser ducts to the overhead distribution duct had become detached.
Technical analysis revealed that the joints had been secured using fire-retardant adhesive tape that had lost its adhesive properties. Furthermore, the investigation found that the maintenance installation of the straps and tape was performed in the reverse order of what was specified in the maintenance manual. The investigation also noted that the manufacturer had since updated the production configuration to eliminate the use of tape in certain areas.
Findings
- The smoke was identified as a thick, white, odorless, and cold substance.
- The primary cause was the deterioration of the adhesive on the fire-retardant tape used to secure duct connections.
- As the joints became loose, escaping air from the distribution system stirred up accumulated dust within the overhead panels, creating the visible smoke effect.
- The maintenance installation of the straps and tape did not follow the correct sequence prescribed by the manual.
- The aircraft's maintenance manual lacked clear illustrations regarding the correct installation configuration for these specific ducts.