B738, en-route, south southwest of Toulouse France, 2015

B738, en-route, south southwest of Toulouse France, 2015


On 25 February 2015, a Boeing 737-800 encountered severe clear air turbulence as it crossed the Pyrenees northbound at FL 380. Two of the four cabin crew sustained serious injuries and it was decided to divert to Bordeaux where the flight arrived 35 minutes later. The turbulence and its consequences were attributed to the flight’s lateral and vertical closeness to a correctly forecast opposite-direction jet stream core and specifically to allowing cabin service to commence despite being near the boundary associated with severe turbulence following a negative ATC response when asked whether other flights had reported severe turbulence.

Event Details
Event Type
Flight Conditions
Flight Details
Type of Flight
Public Transport (Passenger)
Flight Origin
Intended Destination
Actual Destination
Take-off Commenced
Flight Airborne
Flight Completed
Phase of Flight
SSW of Toulouse, France
En-route Diversion
Environmental Factors
CAT encounter
Turbulence Injury - Cabin Crew
Damage or injury
Non-aircraft damage
Non-occupant Casualties
Occupant Injuries
Few occupants
Off Airport Landing
Causal Factor Group(s)
Aircraft Operation
Safety Recommendation(s)
None Made
Investigation Type


On 25 February 2015, a Boeing 737-800 (EI-DAC) being operated by Ryanair on a scheduled international passenger flight from Reus to Brussels South Charleroi as FR 2829 suddenly encountered severe turbulence in the cruise at FL380 in night VMC close to an area forecast to be at risk of this. The resulting flight path upset was brief but significant and the turbulence only ceased following an immediately commenced descent to FL360. Cabin service was in progress and it was subsequently learned that two of the four cabin crew had sustained serious injuries. A diversion to Bordeaux was commenced and on arrival there the two injured cabin crew were taken to hospital. 


A Serious Incident Investigation was carried out by the French Civil Aviation Accident Investigation Agency, the BEA with relevant FDR and CVR data, crew statements and relevant recorded ATC and meteorological data available. The Captain was acting as PF for the sector but no information was published in respect of the total or aircraft type flying experience of either pilot.

What Happened and Why

During their pre-flight preparation, the prevailing meteorological situation was reviewed and the existence of a strong northerly jet stream core between FL 300 and FL 360 just to the east of the aircraft’s almost opposite-direction planned track was noted with clear skies forecast at all levels above FL 300 (see the Significant Weather Chart reproduced below). It was noted that the forecast shear rate for part of the initially planned route (crossing the Pyrenees and the initial part of the track thereafter) was 12 knots/1,000 feet. Since such a shear rate was indicative of severe turbulence, the crew decided to request a modification of their route so that they would fly a track which would take them approximately 3nm to the west of the boundary of the zone covered by the associated SIGMET and this request was approved.

The flight subsequently departed as expected into non-turbulent air and once above the usual FL100, the cabin crew were authorised to commence in flight service. Then, about 15 minutes after takeoff with the flight approaching its planned cruise altitude of FL 380 and still in smooth air and clear of cloud, ATC were asked if they had received any PIREP on turbulence and advised that there had been no such reports. Soon afterwards, as FL380 was reached with the flight still approximately 15 nm from the forecast boundary of the SIGMET turbulence area, a zone of severe turbulence was entered.

Over a period of 12 seconds, FDR data showed that a turbulence-generated loss of control involving the following variations occurred:

  • Vertical acceleration varied between -0.38 g and +1.52 g
  • Longitudinal acceleration varied between 0 g and 0.125 g
  • Pitch varied between +8.4° and -2.5° 
  • Angle of Attack varied between -9° and +10°
  • Bank Angle varied to both left and right up to 19° from level flight
  • Indicated airspeed ranged between 217 KCAS and 256 KCAS

Stick Shaker activation and overspeed warning annunciation occurred as the crew disconnected both the AP and A/TH and began a descent. On reaching FL360, flight path stability and control were restored and the AP and A/THR were re-engaged and ATC informed. 

The flight crew were then informed that although no passengers had been affected by the turbulence episode, two of the cabin crew had been injured and given the apparent relative seriousness of their injuries, it was decided to immediately commence a diversion to Bordeaux. On reaching there without further event, the two injured cabin crew were disembarked and hospitalised. 


The European SIG WX Chart Valid at the time of the Accident. [Reproduced from the Official Report]


The Accident confirmed the difficulty of accurately predicting zones of clear air turbulence with the consequence that any forecast boundaries of an air mass with an identified risk with or without a related SIGMET “must be considered as relatively imprecise”. It was considered that such an understanding would be conducive to a crew taking more appropriate action than in this case to avoid cabin crew and passengers being unnecessarily exposed to risk of injury due to CAT. The Accident also served to show that, whilst PIREPs can, as in this case, be useful if available, their absence absolutely does not guarantee an absence of risk.

Safety Action 

Ryanair as the aircraft operator supplemented the regulatory requirements with the introduction of a new electronic flight plan with a more user friendly format for the display of weather information including the use of colour and a functionality which allows the geographic coordinates to be inserted so that SIGMET adverse weather zones can be added to the electronic charts routinely used during pre-flight preparation.

The Final Report was initially published in the definitive French language version on 25 November 2021 and this was followed on 2 December 2021 by an English Language translation. 

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