On 27 August 2016, debris from sudden uncontained failure of the left CFM56-7B engine of a Boeing 737-700 climbing through approximately FL 310 west southwest of Pensacola in day VMC penetrated the fuselage barrel and caused a rapid depressurisation. An emergency descent and a diversion to Pensacola followed without further event. The Investigation found that collateral damage had followed low-cycle fatigue cracking of a single fan blade due to a previously unrecognised weakness in the design of this on-condition component which, because it had not been detected during the engine certification process, meant its consequences “could not have been predicted”.