Yesterday, we posted on the NatSecDailyBrief about the ACARS-Inmarsat data reports on smoke detected aboard the ill-fated EgyptAir  MSFlight 804.  We noted comments by a commercial pilot on an Aviation Herald article speculating  that there could have been an internal explosion in the nose of aircraft possibly affecting the avionics and fly by wire computer system. That might have caused the downing.

Watch this U.K. Telegraph of Debris recovered from MSFlight 804.

Note what the U.K. Telegraph reported in its blog on the downing  of  MSFlight 804:

Data from the final moments before EgyptAir flight MS804 crashed into the Mediterranean suggest an “internal explosion” tore through the right side of the aircraft, a pilot said last night.

Investigators trying to determine whether the A320 was brought down by terrorism or a technical fault are poring over a series of warnings indicating smoke filled the cabin shortly before it disappeared from radar.

French authorities confirmed that smoke detectors went off aboard the flight a few minutes before it crashed but said it was not clear what caused the smoke or fire.

A commercial pilot with a major European airline told The Telegraph that other parts of the data log suggested that windows in the right side of the cockpit were blown out by an explosion inside the aircraft.

“It looks like the right front and side window were blown out, most probably from inside out,” said the pilot, who flies an A330 similar to the crashed A320 and spoke on condition of anonymity.

[…]

Until investigators find the aircraft’s black boxes, which are still missing in the Mediterranean, the ACARS offers the best sense on what was happening aboard.

Three different warnings showed there were faults in the windows next to the co-pilot, suggesting they could have been blasted outwards by an onboard bomb. That does not mean the explosion came from the cockpit but indicates the right side of the plane was more badly damaged than the left.

The pilot suggested the smoke detectors may have been triggered not fire but by fog which filled the cabin as it lost air pressure in the moments after the explosion.

[…]

According to the Wall Street Journal, people “familiar with the matter” say that the alerts could be an indication of a problem with the flight control system.

While not ruling out a bomb, Bob Mann, a US aviation expert, says the latest data indicate a number of possibilities. “The data could indicate rapid decompression or smoke and a progressive loss of flight control systems.

Note how difficult the French security investigations are looking into the backgrounds of the more than 85,000 workers at the Paris airports and the short interval of conducting the security  sweep on Flight 804:

Although no terrorist group has claimed responsibility, French detectives are examining a pool of around 85,000 people with “red badge” security clearance that gives them access to restricted areas of Charles de Gaulle airport.

The task is complicated by the fact that many work for sub-contractors and turnover is high. Screenings are often limited to checking an employee has no criminal convictions and does not appear on a terror watch list.

Last December around 70 red badges were withdrawn from staff at Charles de Gaulle who were found to have praised the attacks in Paris, prayed at mosques linked to radicalism or showing signs of growing religiosity like refusing to shake hands with women.

A French trade union also warned that short stopovers like that made by Flight 804, which was on the ground a little over an hour, gave little time for security staff to carry out thorough security checks.

Then there were the New York Times reports about graffiti daubed on the aircraft in Cairo back in 2013 saying, “We will bring this plane down”:

It has emerged that the crashed aircraft had once been daubed with graffiti by vandals who wrote: “We will bring this plane down”.

The New York Times reported that the vandalism was done two years ago and was a protest against Abdel Fattah El-Sisi, the Egyptian president who seized power in a coup, rather than a jihadist threat.

The airline went on to fire a number of staff with alleged Muslim Brotherhood sympathies in 2013 as part of a general purge of suspected Islamists after the military takeover.

And in the weeks following the Paris attacks in November, French police said Arabic graffiti such as “Allahu Akbar” (God is great) were found daubed on EasyJet and Vueling planes at Charles de Gaulle airport in Paris and at Lyon airport.

It also emerges that EgyptAir was exempted from a trial of the new French security system for vetting passengers:

Charles de Gaulle airport will begin testing a passenger screening tool known as the passenger name record (PNR) next week. The system, already in use in Britain, identifies passengers whose profiles indicate a potential risk. It cross-references names, addresses and means of payment with police crime and terrorism files.

However, EgyptAir will not be among the eight airlines that will take part in the trial, which the interior minister, Bernard Cazeneuve, says is long overdue.

The system is to become fully operational by the end of the year in France, which has received nearly £14 million in EU aid to finance its introduction.  It can detect passengers who have travelled to countries such as Syria and Yemen, with their return dates.

The evidence keeps piling up that supports the  comments of ex-CIA director Ambassador Woolsey and  investigations by the Lisa Benson Show National Task Force for America that international airports, including those in the US,  are not secure.  That is particularly acute given the difficulty of profiling airport workers with security access to aircraft on the tarmac and now we learn vetting passengers from terrorist hot spots.

EDITORS NOTE: This column originally appeared in NatSecDailyBrief.