EGYPTAIR: Absence of distress beacon suggests terrorism
The fate of EgyptAir flight MS804, and the 66 souls on board, is still unknown. Any number of events could explain the loss of the Airbus A320 over the Mediterranean on a scheduled flight from Paris Charles de Gaulle to Cairo.
But as with the Metrojet A321, which crashed in the Sinai Desert last October on a flight from Sharm El Sheikh to St Petersburg, the apparent absence of any distress signal means that the possibility of terrorism will loom large in investigators' minds.
Within aviation, the key issue that keeps airport and airline bosses awake at night is security - and, in particular, "insider threat". At an airport such as Charles de Gaulle, tens of thousands of employees have access "airside". While checks for staff are generally as rigorous as for passengers, an insider who understands the movement of goods to airside locations is regarded as a potential threat.
It is thought that the Metrojet crash, in which 224 people died, was caused by a bomb placed on board the plane while it was on the ground at Sharm El Sheikh. Shortly after the crash, the Foreign Office banned UK airlines from flying to the airport in Egypt's premier resort because of concerns about the quality of security checks. That prohibition remains in place, and the absence of British holidaymakers through the winter has caused immense damage to the nation's tourist economy.
The work to discover what cause the loss of MS804 will be painstaking, and is likely to involve literally piecing together the wreckage. If investigators conclude that an explosive device was placed - or carried - on board, the next question is where that act of terrorism took place.
The aircraft had flown in from Cairo on Tuesday afternoon. Checks of the cabin and the holds are routinely made, but at this stage the possibility that something was placed on board in the Egyptian capital cannot be ruled out. If that were the case, confidence in the nation's airports would be wrecked - and the damage to Egypt's ailing economy would be immense.
Conversely, if it were thought that an insider at Paris CDG was responsible, travellers' faith in global aviation would be shaken. The French capital's main airport is the busiest in Continental Europe, and an extremely important hub.
While the search and recovery operation gets under way, airports and airlines will be looking intently at their operations - and who gets access to them.
After the Metrojet tragedy in October, the aviation security expert Philip Baum noted that many airport employees are "low-paid, transient workers," and said: "Identifying 'bad eggs' is no easy task, especially in an environment which is driven by speed, customer service and on-time performance."