The shocking event today of the Fly Dubai Boeing that plummeted 17,000 feet before being recovered and landing safely, reveals a series of fortunate coincidences that prevented a worse tragedy. Although information is still very limited, it seems that one of the two pilots attacked the other with a knife, intending to either crash or hijack the aircraft.
By chance there was a positioning crew on board as passengers and once the cockpit was accessed and the attacker subdued, they were able to take control and land the aircraft safely, albeit with some degree of structural damage to the tail of the plane. In all normal circumstances it is impossible to get access to the flight deck since the 2001 attacks in New York. There are various ways that the cockpit is secured and we cannot discuss them here but thankfully either the pilot under attack or the on board crew had access, which saved the day.
In 2015 a German Wings Airbus was deliberately crashed by the co-pilot when he locked the captain out and nobody was able to get back onto the flight deck to save the airliner and its passengers. This is a potential price we pay for security measures designed to stop bad actors booked as passengers from hijacking an aircraft.
It is an extraordinary set of coincidences have come together today to create a different outcome than the one that somebody intended. Investigators will also need to ascertain how a weapon was on the aircraft in he first instance. Crew are subjected to the same security inspection as passengers.