What happened
On 14 February 2011, an Emirates Boeing 777-300ER, registration A6-ECE, was operating a scheduled passenger service from Dubai International Airport to New York's John F. Kennedy International Airport. During the cruise phase of the flight, cabin crew members alerted the flight deck to a pungent odor in the aft section of the cabin, described as smelling like sulfur or rotten eggs, alongside a scent of burning rubber.
Due to the increasing intensity of the smell and the inability to identify its source, the captain made the decision to divert the aircraft to Stockholm Arlanda Airport. The aircraft landed at its maximum landing weight without further incident. Following maintenance procedures at the destination, the aircraft continued its subsequent flight operations.
The investigation
The GCAA AAIS, in coordination with the Swedish Accident Investigation Authority (SHK) and the NTSB, conducted a technical examination of the aircraft's environmental control systems. Investigators focused on the heat exchanger, the condenser/reheater, and the ozone converter.
Laboratory analysis using Fourier Transform Infrared (FTIR) Spectroscopy was performed on the ozone converter. This testing identified the presence of silicone oil, a substance used as an installation aid, though it was not considered a source of the odor. Inspections of the heat exchanger and condenser/reheater revealed no foreign contamination or mechanical defects that could have produced the sulfurous smell.
Findings
- The primary cause of the unpleasant odor could not be determined through the investigation.
- The aircraft was airworthy and maintained in accordance with all regulatory requirements.
- There were no injuries to passengers or crew.
- While the ozone converter was a suspected source because the odor subsided when the right pack was turned off, physical examinations of the unit did not reveal any identifiable cause for the sulfur-like scent.