Serious incident to the Boeing 737-800 registered F-GZHM operated by Transavia on 13/02/2019 en route off the coast of Montenegro
Turbulences sévères en croisière
During a flight from Lyon to Tel Aviv, when the aeroplane was en route at FL 370 off the coast of Montenegro, the air traffic controller informed the crew that a previous aeroplane had reported severe turbulence between FL 380 and FL 400. This information was taken into account and transmitted to the purser. The pilots switched on the seatbelt signs less than a minute later. The cabin crew were checking that the passengers had their seatbelts fastened when the severe turbulence started. A few passengers, including some who had been asked by the cabin crew to fasten their seatbelts, did not have their seatbelts fastened at this point and were injured. The cabin crew stationed at the rear of the cabin did not have time to fasten their seatbelts and were also injured.
In the event of unforeseen severe turbulence, in particular clear air turbulence, the operating manual requires the crew to tell the cabin crew that due to turbulence, they must sit down and fasten their seatbelt. The crew were concentrated on controlling the aeroplane. Furthermore, the very short lapse of time between the illumination of the seatbelt signs followed by the passenger announcement and the occurrence of the severe turbulence did not allow the cabin crew to check all of the cabin and to fasten their seatbelts. It is common to have light turbulence and it was not possible for the cabin crew to know the magnitude of the turbulence to come and to assess the urgency of fastening their seatbelts.
These observations bring to light the intrinsic limitation of the procedures concerning unforeseen turbulence: the unpredictability both in terms of the time of the occurrence and strength of the turbulence means that these procedures cannot be applied in a timely or correct manner. The only way of limiting the risk of injury at this time is for passengers to comply with the instructions to keep their seatbelt fastened when they are seated.
