At 0749 Eastern Standard Time on 17 April 2012, a Boeing Company 737-7Q8 aircraft,  egistered VH-VBL (VBL), departed Melbourne, Victoria, on a scheduled passenger service to Sydney, New South Wales.

The captain reported a burning smell in the cockpit on takeoff that dissipated at the top of climb. Shortly afterwards, the cabin supervisor advised the PIC of a very unusual smell in the front and rear of the passenger cabin.

The cabin supervisor and one other cabin crew member reportedly suffered minor side effects from the fumes. Another cabin crew member was unable to continue with his duties. As there was an extra cabin crew member on the flight, the supervisor assessed that his inability to continue with his duties did not pose a risk to flight safety.

After landing and following a review of the maintenance log, a company engineer advised that the fumes may have been the result of a recent engine wash.

No passengers reported feeling unwell during or following the flight, though some passengers in the front of the cabin were coughing during the flight. The captain at no time felt unwell and the first officer did not smell anything unusual throughout the flight.

Two of the cabin crew members were later deemed by a doctor to be unfit for work. 

The incident highlights the potential for crew incapacitation from exposure to fumes and that clear and unambiguous communication between the flight and cabin crew should be maintained during any unusual event.

Aviation Short Investigation Bulletin - Issue 12