Created Thursday, Nov 25th 2021 15:11Z, last updated Thursday, Dec 2nd 2021 15:17Z
A Ryanair Boeing 737-800, registration EI-DAC performing flight FR-2829 from Reus,SP (Spain) to Brussels Charleroi (Belgium) with 164 people on board, was climbing through FL375 over the Pyrenees about 30nm west of Andorra at about 19:47L (18:47Z) when the aircraft encountered severe turbulence causing serious injuries to two flight attendants. The aircraft descended to FL360 and subsequently diverted to Bordeaux (France) for a safe landing. The injured flight attendants were taken to a hospital.

Bordeaux Airport reported the aircraft encountered severe turbulence causing a broken ankle to one and a back injury to the other flight attendant. The broken ankle was caused by a trolley falling onto the flight attendant.

The airline reported the aircraft encountered "some turbulence", two flight attendants received minor injuries and were taken to a hospital.

On Mar 3rd 2015 the French BEA reported in their weekly bulletin, that two flight attendants received serious injuries when the aircraft encountered severe turbulence while levelling off at FL380. The occurrence was rated an accident, the BEA is investigating.

A replacement Boeing 737-800 registration EI-ESR continued the flight to Charleroi as flight FR-2289 and reached the destination with a total delay of 5 hours.

The occurrence aircraft departed Bordeaux for Barcelona,SP (Spain) about 5 hours after landing and remained on the ground in Barcelona for about 13 hours before resuming service.

On Nov 25th 2021 the BEA relased their final report in French only concluding the probable causes of the accident were:

Scenario

Prior to departure, during flight preparation, the crew requested a modified route due to the risk of strong turbulence along the planned route. The modified route went west of the area for which strong turbulence had been forecast. After departure shortly before reaching cruise altitude, the crew queried the air traffic controller for any pilot reports of turbulence and received the response that no turbulence was known along their modified route. When the aircraft came near the area, that SIGMET had identified as zone of severe turbulence, the aircraft entered turbulence the onset of which was so sudden and violent that two flight attendants received serious injuries while performing their duties.

Contributing factors:

The new trajectory as requested during flight preparation, the absence of turbulence during the climb, the absense of any report of turbulence along the modified route may have gradually led the crew to underestimate the risk. The captain thus permitted the cabin service to commence during the climb and its continuation until the aircraft experienced severe turbulence in the vicinity of an area that SIGMETs had identified as an area of risk.

Safety lessons

The accident confirms the difficulties of accurately predicting areas of turbulence in clear air. A risk identified by e.g. SIGMETs must be considered as a relatively imprecise indication. If operational constraints require nearing such areas of risk the crew must take appropriate precautions to avoid exposing cabin crew and passengers to the risk of injury. Pilot weather reports (PIREPs) are encouraged to share information with other pilots who may be exposed to the same hazardeous phenomemon in nearby area and time. The existance of a PIREP can increase the vigilence, the absense of PIREPs does not guarantee the absence of risk.

As the BEA has pledged to release English reports as soon as practicable, a summary of the analysis will be released at that point in time.

On Dec 2nd 2021 the BEA released their final report analysing:

Meteorological information

A strong high-pressure system off the coast of Portugal and a low-pressure system over Sicily were channelling a strong north jet stream(2) over France, the strongest jet core being east of the aeroplane¡¯s flight path, between FL 300 and FL 360.

The meteorological conditions estimated by M¨¦t¨¦o-France in the sector of the accident were: wind from 360¡ã at 100 kt at FL 340 and from 360¡ã at 90 kt at FL 380, clear sky above FL 300, temperature -58¡ãC at FL 340 and -64¡ãC at FL 380, severe turbulence.

The following meteorological information was available before the accident:

SIGMET FIR Bordeaux
LFBB SIGMET 6 VALID 251700/252000 LFPW
LFBB BORDEAUX FIR/UIR SEV TURB FCST WI N4330 E00245 - N4215 E00230 - N4245 W00100 - N4300 W00100 FL350/430 STNR NC=
LFBB SIGMET 7 VALID 252000/252300 LFPW
LFBB BORDEAUX FIR/UIR SEV TURB FCST S OF LINE N4315 E00230 ©\ N4245 W00100 FL350/440 STNR NC=

Preparation of flight and flight path followed

While preparing the flight, the crew asked for a track modification due, in particular, to the shear rate value. In the initial flight plan, the shear rate was 12 kt/1,000 ft for one of the sectors. With the new track, the crew would fly alongside the air mass concerned by SIGMET 6, at approximately three NM to the west.

The information collected during the investigation did not include information about the forecast shear rates on the new track.

The turbulence occurred at around 15 NM from the air mass concerned by SIGMET 6.

The crew indicated that, based on the weather information that they had at their disposal, they had not noted a particular risk of severe turbulence in the sector of the accident.

Detailed information concerning recorded data

From 18:48:57 and for 12 s, the analysis of the recorded data showed:
ˆ- Vertical accelerations between -0.38 g and +1.52 g.
-ˆ Longitudinal accelerations between 0 g and 0.125 g.
-ˆ Variations in pitch between +8.4¡ã (nose up) and -2.5¡ã (nose down).
-ˆ Variations in angle of attack between -9¡ã and +10¡ã.
-ˆ Variations in left and right bank, up to 19¡ã.
-ˆ Variations in the indicated airspeed between 217 kt and 256 kt(4).

Assessment of clear air turbulence risk level

In its 2020 Annual Safety Review, EASA indicated that the majority of the injuries (other than fatal) recorded in commercial air transport, in the large aeroplane category, for the 2009-2019 period were the result of in-flight turbulence (whatever the nature of this turbulence). However, according to the ERCS method, EASA assessed the risk associated with clear air turbulence as being low. EASA puts all the safety issues concerning commercial air transport by large aeroplanes into three safety level categories. In its risk map, EASA positions clear air turbulence in the second safety level category.

In 2020, the BEA published an investigation report into a serious incident resulting from clear air turbulence. This report underlined the absence of reliable means for forecasting and detecting clear air turbulence.

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