Alexander had taken his first flying lesson in 1967 and had accrued 1,500 flying hours by the time of his death. Onassis' poor eyesight meant that he could not hold an air transport certificate, but could possess a commercial pilot certificate, allowing him to fly light planes and air taxis for emergency medical cases. Alexander died on January 23, 1973, at the age of 24 from injuries sustained the previous day when his personal
Piaggio P.136L-2 amphibious airplane, in which he was a passenger, crashed at
Hellinikon International Airport in Athens. Alexander was instructing a potential new pilot of the plane, Donald McCusker, at the time of the crash, in his role as President of
Olympic Aviation. Alexander and McCusker were accompanied by Donald McGregor, Onassis's regular pilot, who was recovering from an eye infection. A few seconds after takeoff from runway 33, the plane's right wing dropped and stayed down, and the plane crashed shortly after losing control in a flight lasting no more than 15 seconds. McCusker and the other pilot both suffered serious injuries in the crash. The trio had planned to practice amphibious landings between the
Saronic Gulf islands of
Aegina and
Poros after takeoff. The day after the crash, Alexander's father and stepmother arrived from New York at the hospital where Alexander was being treated. The couple were accompanied by an American neurosurgeon. Alexander's mother arrived from Switzerland with her husband, Stavros Niarchos. Alexander Onassis was buried next to the chapel on his father's private
Ionian island of
Skorpios. Reports into the crash by the
Greek Air Force and an independent investigator hired by Onassis, the Englishman Alan Hunter, concluded that it had occurred as a result of the reversing of the
aileron connecting cables during the installation of a new control column. This conclusion was disputed by McGregor, who believed that the
wake turbulence from an
Air France Boeing 727 that had taken off before them had caused the crash. Less than a month after Alexander's death, McCusker had
manslaughter proceedings initiated against him by the public prosecutor of Athens in connection with the crash. Six people were also charged over Onassis's death in January 1974, with their indictment indicating that faulty controls had been fitted to his plane. In December 1974, in a paid advertisement, Aristotle Onassis announced his offering of a
$1,000,000 reward (equivalent to $ million in ) for proof that his son's death had been as a result of "deliberate action" as opposed to the cause of negligence, the conclusion reached by the official inquiry. All charges relating to the crash were later dropped, and McCusker was awarded $800,000 in 1978 by
Olympic Airways, three years after Aristotle Onassis's death. Onassis had refused to believe that his son's death was an accident, believing it was due to the machinations of the United States
Central Intelligence Agency (CIA) and the leader of the
Greek military junta,
Georgios Papadopoulos. Alexander's death had a profound effect on his father, who never fully recovered from the loss of his son. Aristotle Onassis sought to sell Olympic Airways after his son's death, and died two years later in March 1975. Onassis was buried alongside his son on
Skorpios. ==Alexander S. Onassis Foundation==