On 29 October 2019, an Airbus A321 was descending towards its destination, Kaohsiung, when the First Officer suddenly lost consciousness without warning. The Captain declared a MAYDAY and with cabin crew assistance, he was secured clear of the flight controls and given oxygen which appeared beneficial. He was then removed to the passenger cabin where a doctor recommended continuing oxygen treatment. On arrival, he had fully regained consciousness. Medical examination and tests both on arrival and subsequently were unable to identify a cause although a context of cumulative fatigue was considered likely after three consecutive nights of inadequate sleep.

On 27 September 2017, a Boeing 777-200LRF Captain left the flight deck to retrieve their crew meal about 40 minutes after departing Abu Dhabi but whilst doing so he collapsed unconscious in the galley and despite assistance subsequently died. A MAYDAY was declared and a diversion to Kuwait successfully completed by the remaining pilot. The Investigation determined that the cause of death was cardiopulmonary system collapse due to a stenosis in the coronary artery. It was noted that the Captain’s medical condition had been partially concealed from detection because of his unapproved use of potentially significant self-medication.

On 21 January 2019, a Piper PA46-310P en-route north northwest of Guernsey was reported missing and subsequently confirmed to have broken up in flight during an uncontrolled descent. The Investigation found that neither the pilot nor the aircraft involved were able to be used for commercial passenger flight operations but also found that although the direct cause of loss of control was unproven, it was most likely the consequence of carbon monoxide poisoning originating from an exhaust system leak. The safety implications arising from operation of private flights for commercial passenger transport purposes contrary to regulatory requirements were also highlighted.

On 15 August 2016, the cognitive condition of an Airbus A320 Captain deteriorated en-route to Riga and he assigned all flight tasks to the First Officer. When his condition deteriorated further, an off duty company First Officer travelling as a passenger was invited to occupy the flight deck supernumerary crew seat to assist. Once descent had commenced, the Captain and assisting First Officer swapped seats and the flight was thereafter completed without any further significant event. The Investigation concluded that the Captain’s serious physical and mental exhaustion had been the result of the combined effect of chronic fatigue and stress.

On 15 August 2018, a Boeing 737-300SF crew concerned about a small residual pressure in a bleed air system isolated after a fault occurred en-route then sought and were given non-standard further troubleshooting guidance by company maintenance which, when followed, led directly and indirectly to additional problems including successive incapacitation of both pilots and a MAYDAY diversion. The Investigation found that the aircraft concerned was carrying a number of relevant individually minor undetected defects which meant the initial crew response was not completely effective and prompted a request for in-flight assistance which was unnecessary and led to the further outcomes.

On 17 November 2017, an Airbus A320 flight crew were both partially incapacitated by the effect of fumes described as acrid and stinging which they detected when following another smaller aircraft to the holding point at Geneva and then waiting in line behind it before taking off, the effect of which rapidly worsened en-route and necessitated a precautionary diversion to Marseilles. The very thorough subsequent Investigation was unable to determine the origin or nature of the fumes encountered but circumstantial evidence pointed tentatively towards ingestion of engine exhaust from the aircraft ahead in one or both A320 engines.

On 31 December 2017, a de Havilland DHC2 floatplane being manoeuvred at low level over Jerusalem Bay shortly after takeoff was observed to enter a steeply banked turn from which it appeared to depart controlled flight and impact the water surface below almost vertically. The Investigation concluded that the aircraft had stalled despite the exemplary proficiency record of the pilot and that in the absence of any other plausible explanation found that the loss of control was likely to have been the effect of an elevated exposure to carbon monoxide found during post mortem toxicology testing.

On 6 July 2011 the First Officer of a Ryanair Boeing 737-800 was suddenly incapacitated during a passenger flight from Pisa to Las Palmas. The Captain declared a medical emergency and identified the First Officer as the affected person before diverting uneventfully to Girona. The subsequent investigation focused particularly on the way the event was perceived as a specifically medical emergency rather than also being an operational emergency as well as on the operator procedures for the situation encountered.

On 13 April 2015, a Swearingen SA226 Metro II which had recently departed on a cargo flight was climbing normally when it suddenly entered an unexplained and steep descent a few minutes after takeoff. There were no communications from the pilots. It was later found to have impacted terrain after a rate of descent exceeding 30,000 fpm had created aerodynamic forces which caused structural disintegration to begin before impact. The Investigation could not determine why but concluded that “alcohol intoxication almost certainly played a role” and noted that indications that the Captain was a chronic alcoholic had not prompted any intervention.