In February 2011, six people including two pilots, died when the Manx2 Belfast to Cork flight crashed while making its approach to land in the Irish city.Just before 10am on Tuesday 10 February and in foggy conditions, the aircraft, while making its third approach to the airport, hit the runway before flipping and landing on its roof.Four of those that died were from Northern Ireland.They were Brendan McAleese, Pat Cullinan, Michael Evans and Richard Noble.On Tuesday, the Air Accident Investigation Unit (AAIU) published its findings into the cause of the crash.It described its investigation of the incident as one of the most challenging in its 20 year history.The AAIU said working with the Spanish operator, the Isle of Man based ticket seller and the Spanish owners of the aircraft added to the complexities of their investigation.Its main finding was that control of the aircraft was lost as it approached the airfield and that the tiredness and fatigue of the flight crew members played a significant role.It also said the difficult weather conditions played a role in the incident and raised concerns over the crew's training.Report into Cork air crash of Feb 2011 blames crew tiredness and inadequate training of main pilot along with other factors— Jamie Delargy (@Jamie_utv) January 28, 2014As part of the report, investigators said significant factors included:Visibility was below the required level for a safe landing.The pilots continued to descend without acquiring an adequate visual reference.There was an uncoordinated operation of the flight and engine controls.Engine power was reduced to below normal levels during the approach.There was inadequate command training and checking as well as inappropriate pairing of flight crew members.There was inadequate oversight of the remote operation and the State of the operator.The report said: "Systemic deficiencies at the operational, organisational and regulatory levels were also identified by the investigation."Such deficiencies included pilot training, scheduling of flight crews, maintenance and inadequate oversight of the operation by the operator and the state of registration."A total of 11 recommendations have been made in the report to prevent a similar crash happening again.They include flight time limitations, the role of the ticket seller and improvement in safety oversight.As well as training, staff appointment and civil aviation oversight recommendations, the report also advises implementing guidelines in regard to the number of landing approaches a plane can make in certain weather conditions.The report said: "The AAIU recognises that this is a difficult time for those families who lost loved ones and the surviving passengers who suffered injuries in this tragic accident. Our deepest sympathies to all concerned."The AAIU wishes to acknowledge the patience and understanding shown by all affected families while the unit fulfilled its legal obligation to complete a detailed and independent safety investigation."The most cursory review of the report clearly indicates that there are significant issues to be addressed in the wider aviation industry, as well as issues directly related to the accident.Captain Evan Cullen, IALPAThe Irish Airline Pilots' Association (IALPA) branch of trade union Impact has welcomed the recommendations.IALPA president, Captain Evan Cullen, said: "Our thoughts and sympathies are with the bereaved families of the flight crew and passengers at what will be a very difficult time for them as they revisit the tragic circumstances of their profound loss."The report clearly indicates that regulatory, technical and human factors were centrally involved in this tragic accident."It is clear to IALPA that the voices of professional pilots operating on the front line of aviation need to be heard and listened to at every level of the industry, to ensure we minimise the possibility of such an accident happening again" he said.Captain Cullen said that many of the conclusions in the report clearly indicated that minimum standards were operated at "every level" of the commercial operation of the flight.He said IALPA welcomed the recommendation calling for rigorous improvements in the regulatory regime."If these recommendations are fully implemented, they will help to reduce the commercial practices that rely entirely on the use of minimum standards, and help to ensure that such a tragedy can be avoided in the future."We will review this report in detail and provide a more comprehensive response on behalf of our professional pilot community."Cork Airport, managing director, Niall MacCarthy praised the emergency services for their response on the day.He said: "This is another difficult day for the families and friends of the six men who lost their lives in the accident, and our thoughts are with them and those who were injured."I wish to commend the emergency services for their response to the incident, and in particular the members of the Airport Fire Service who were first on the scene."The AAIU's report contained no recommendations in relation to the operation of Cork Airport.The airline which operated the service is no longer in business. Manx2 says the report makes it clear it wasn't at fault over the crash.