Initial evidence provided at air traffic controller stations and at the assumed crash site in the Eastern Mediterranean has proved inconclusive. Let’s consider what hypotheses the aircraft's black box, if found, may seek to confirm or invalidate.
In terms of the mechanical failure theory, data from MS804’s Aircraft Communications Addressing and Reporting System (ACARS) detected that smoke alarms had been triggered minutes before signal with the aircraft was lost approximately 16km within Egyptian airspace.
Disputed accounts also suggest that the aircraft made irregular movements during the course of its flight path in Greek airspace. However, no technical faults were found on the aircraft prior to its departure and it remains unclear as to whether any distress signal was emitted by the airliner over the course of its flight path.
At the suspected crash site in the Eastern Mediterranean, rescue and recovery personnel have allegedly collected debris, personal belongings and up to 20 bags of human remains which were found floating in open waters.
The fragmentation of the debris and human remains led some civil aviation experts to suggest that an explosion may have occurred aboard the aircraft – a claim which remains disputed but which neither affirms nor refutes the mechanical/technical fault hypotheses.
In terms of an explanation involving terrorism, it is worth highlighting that there have been no immediate claims of responsibility for the downing of MS804.
This is somewhat anomalous for transnational terrorist groups such as the Islamic State (IS) and al-Qaeda, who generally release communiqués claiming attacks, particularly those of a high-profile nature, within days, if not hours, of high-profile attacks.
This was highlighted following the October 2015 downing of Metrojet flight 9268, en route from Sharm el-Sheikh (Egypt) to Saint Petersburg (Russia), which was claimed by semi-official IS social media accounts hours after the crash was confirmed.
But this does not preclude the downing of MS804 as potentially being an act of terror. Domestic or transnational terrorist organisations may have withheld their claim of responsibility to conceal the method in which the aircraft was downed, with the intention of repeating further such attacks. Such a modus operandi would not be uncharacteristic within the Islamist extremist fraternity.
In its post-mortem of the Egyptian airliner’s crash, global intelligence firm Stratfor references the 1994 downing of Philippine Airlines Flight 434 by an improvised explosive device (IED) comprised of components concealed in items such as modified shoe heels and a digital watch.
The bomb attack, which killed one person and wounded 10 others, was not immediately claimed by its orchestrator, senior al-Qaeda operative Ramzi Yousef.
This was due to the fact that Youssef was to use the same means of smuggling and detonating IEDs aboard a further 11 Trans-Pacific flights operating between Asia and the United States; these attacks were to form part of the infamous Bojinka plot.
However, this hypothesis is somewhat problematic given that IS claimed responsibility for Metrojet 9286 without disclosing the purported IED used in the attack. It was only with the release of 12th edition of its English propaganda magazine Dabiq, in which the group disclosed that it downed Metrojet 9286 via an IED which has since become known as the Schweppes bomb.
A second, and perhaps more plausible, terrorism theory is that a lone actor may have been responsible for the attack and the propaganda machinery of terrorist networks are yet to receive confirmation of an act of violence committed on their behalf.
So-called lone wolf or self-radicalised actors have previously attempted to target commercial aviation interests in acts of terrorism. This was perhaps best exemplified by the 2001 attempted bombing of American Airlines Flight 63, en route from Paris to Miami, by self-proclaimed al-Qaeda operative Richard Reid.
However, the ability to smuggle, detonate and successfully down an aircraft mid-air would require a highly skilled and sophisticated actor which significantly decreases the possibility that the downing of EgyptAir MS804 was the work of an independent operator.
Indeed, even when such attacks are planned and orchestrated by highly sophisticated terrorist organisations – as was noted by the underwear bomber plot linked to al-Qaeda in the Arabian Peninsula (AQAP) – the end result is most certainly not guaranteed.
Until there is conclusive evidence, both a technical malfunction and an act of terrorism remain equally possible causes of the downing of MS804. Precedent suggests that investigations to provide a definitive answer are likely to take months, if not years, to complete.
In the interim, the global aviation sector will continue to serve as a high value target for terrorist organisations with plots aimed at executing a successful attack probably being devised with a greater degree of urgency.