Whatever triggered a meltdown of the Airbus’s flight controls could also have brought instant death in the cockpit.
Among the many questions raised by the EgyptAir Flight 804 tragedy, the most perplexing concerns one thing that did not happen: Why was there no Mayday distress call from the pilots?
Experts are struggling to interpret and explain the seven brief bursts of data sent via satellite from the airplane that describe a cascade of mechanical failures ending with the loss of primary controls. Some kind of explosion involving smoke and fire at the front of the cabin is indicated but not in enough detail to give an understanding of the cause.
Like most modern jets the Airbus A320 is “fly-by-wire,” meaning that none of its controls is operated by direct physical input from the pilots as in the days of “seat of the pants” aviation. Normally all control passes through the flight management system and is dependent on computers. Even when the autopilot is disengaged and the airplane is flown “manually” bypassing the computers, the control surfaces are activated electronically.
(On Airbus airplanes the pilots use sidesticks similar to those on a video game to send commands while Boeing retains the traditional “yoke” centered in front of the pilots replicating the joystick of older generations—although the system is still “fly-by-wire.”)
Whatever happened to the Airbus within a very few minutes, it essentially fried the computers and command system and rendered the controls inoperable, something never seen before in a modern jet.
Normally in a fire and smoke emergency the pilots would have time to don smoke masks with microphones in them, and would be able to send a Mayday, and describe the problem. The Egyptian pilots clearly were never able to do this, suggesting the possibility that they were either disabled or killed at the onset of whatever overcame the airplane so rapidly.
What did actually happen in that cockpit cannot be known until the main parts of the airplane, together with its flight data recorders, are found. That is likely to be a prolonged and extremely arduous operation.
The debris so far recovered is poignant in its connection to passengers—an unused life vest, pieces of luggage, part of a seat—but is far too fragmentary to offer any clues to what happened.
It also offers no guidance to where the actual crash site is. The light debris was carried rapidly on currents away from where it must have first appeared.
Unless substantial pieces of the Airbus A320 are found still on the surface—and there is so far no sign of that—the bulk of the wreckage that holds the key to what destroyed the airplane will be lying as far as 10,000 feet down on the seabed.
A French vessel equipped for undersea searches and wreck retrieval has left the port of Toulon and should arrive in the area by Monday (the French have long been leaders in underwater exploration), and the Egyptians are deploying a submarine used for undersea geological surveys for oil.
Just how formidable is the search going to be? As it happens, there is a way of demonstrating the many challenges involved because of an eerie coincidence.
On December 28, 2014 an identical jet, an Airbus A320 flown by AirAsia, fell from 37,000 feet—the height at which the Egyptian jet was cruising—into the Karimata Strait, in the Java Sea, with the loss of 162 lives. (The pilots had pulled a circuit breaker not meant to be touched in flight and disengaged the autopilot, and then lost control.)
The AirAsia jet had not been structurally compromised in its dive and did not break up until it hit the water. Although we now know that the EgyptAir jet’s controls were fatally disabled there is no indication that it broke up in the air.
The dynamics of the way both airplanes dived toward the ocean were similar but exactly how they hit the water would not necessarily be the same. In any event, the heaviest parts, including the main fuselage, would instantly sink and they happen to be the most essential for investigators to reach.
And
so, even though the site was quickly found and accessible, recovery was
still prolonged and difficult. It was another two weeks before the
largest part of the wreck, most of the fuselage with one wing still
attached, was discovered, followed soon afterward by both the flight
data recorder and the cockpit voice recorder.
Finding the EgyptAir jet is a task of an altogether greater magnitude. This is not the Mediterranean of tourist brochures: warm, limpid and inviting. The great depth means the intense darkness of the abyss and the presence of a lot of turbulence—right now, for example, the weather has deteriorated and there are rough seas.
This all makes it unlikely that signals from the locator beacon on the airplane’s flight data recorder will be easily detected. As I have earlier reported, this device is grossly inadequate for conditions like these, and with a battery life of only 30 days there is a pressing deadline to find it.
http://www.thedailybeast.com/articles/2016/05/23/were-egyptair-flight-804-pilots-killed-before-they-could-send-a-mayday.html
The plane reported a series of escalating alarms and failures before it crashed, which began with smoke in a bathroom.
Shortly before EgyptAir Flight 804 began its plunge
toward the Mediterranean Sea, the unit that monitors the airplane’s
critical systems reported a rapid series of alarms indicating smoke in a
lavatory and a breakdown of the flight control system.
This is according to a report in Aviation Herald, a specialist aviation website, and confirmed by French civil aviation investigators in The Washington Post.
The Herald says that it has information from three independent sources that seven emergency alerts were reported by the Airbus’s Aircraft Communications and Reporting System, ACARS, before all communications from the airplane stopped.
The sequence begins with the detection of problems with windows in the cockpit and with smoke in a lavatory.
A minute later, Greek air traffic control said it had tried to contact the plane’s pilots but they did not respond.
The most serious and instantly consequential warning indicates that there was a failure of the avionics that immediately affected the flight controls. This included the autopilot when it would have been flying the airplane at cruise altitude and almost immediately the problem spread to computers operating two critical control surfaces, the elevators at the tail and spoilers that control the airplane’s rate of descent.
The result of these failures would almost certainly mean that the pilots had no opportunity to regain control.
At the same time that the transponder and ACARS system quit sending information, Greek civil radar lost track of the plane.
It cannot be known whether this apparent fire was the result of a bomb or an accident unless and until physical evidence in the form of airplane debris and passengers bodies are collected.
It is significant that the Airbus’s ACARS reporting system is the only live link between the airplane and the ground that gives specific indications of an emergency. The messages are sent in bursts via satellite to the airline’s maintenance base—under normal conditions to indicate a problem that could need attention once the airplane lands.
It was ACARS that provided the first and eventually essential clues to a loss of control of Air France Flight 447 over the south Atlantic in 2009. In the absence of real-time live tracking of airplanes, a scandalous state of affairs, ACARS becomes vital to investigators in a situation like the crash of the EgyptAir 320 where the remains of the airplane can be beyond reach for weeks or even years.
http://www.thedailybeast.com/articles/2016/05/20/bomb-or-fire-appears-to-have-doomed-egyptair-flight-804.html
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