On 6 July 2018, soon after a Boeing 737-800 en-route to Fuerteventura had begun its cleared descent from FL370 to FL130, the controller changed the clearance limit to FL360 after noticing a previously overlooked potential loss of separation with traffic below at FL350. The attempt to level off as instructed resulted in a mismanaged manual intervention which led to an upset lasting about a minute during which a passenger carrying a small child fell and sustained serious injury. The significant delay in getting the injured passenger to hospital after landing led to systemic deficiencies in airport medical assistance being identified.