Editor’s Note: Les Abend is a Boeing 777 captain for a major airline with 31 years of flying experience. He is a CNN aviation analyst and senior contributor to Flying magazine. The opinions expressed in this commentary are solely those of the author.
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Les Abend: Cockpit voice recorder from EgyptAir804 crash appears to indicate a pilot may have been putting out a fire
The significance of this? The plane may not have come down due to terrorism. Mechanical failure a possibility, he says
It appears that EgyptAir 804, which crashed into the Mediterranean Sea on May 19, killing all 66 people on board, may have suffered a significant smoke and fire event.
Although the transcript of the cockpit voice recorder, or CVR, has not been publicly revealed, EgyptAir sources have released information that indicates, from cockpit conversation, that one of the pilots may have been attempting to extinguish a fire or eliminate smoke.
In addition, according to earlier details from the Egyptian Accident Investigation Committee, recovered wreckage from the forward section of the A-320 shows evidence of “thick, black smoke” and heat damage.
Why is this significant? Simply stated, the crash of EgyptAir 804 may not have occurred as a result of terrorism. While investigators still don’t know exactly what caused the crash, both the CVR information and the wreckage evidence lend credence to the theory that a mechanical problem may have created a fire or overheat problem.
It would seem that the source of the event originated from the electronics bay or the cockpit.
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To recap: Before the crash, the messages transmitted to the Aircraft Communications Addressing and Reporting System Aircraft, or ACARS, a data link for sending messages between planes and ground facilities, indicated a fault warning for the copilot’s side window anti-ice heater, which always remains on throughout any flight.
The next two faults in the sequence involved sensors that detect a cockpit window being opened, an impossible task for an airplane pressurized at an altitude of 37,000 feet. And then a warning was sent indicating that smoke was detected both in the forward lavatory and the electronics bay. The electronics bay is just below the cockpit.
Finally, the last two messages transmitted a fault in the autopilot system and then a fault in a portion of the flight controls.
What does all the new evidence imply? Again, we don’t know all the facts yet, but it is possible that a mechanical malfunction within the A-320’s systems may have begun as an overheat situation and erupted into a fire inside the confines of the electronics bay.
The electronics bay is the brains of the airplane. The bay contains the flight management computers that direct almost every aspect of airplane operation: communications, flight control movement, environmental systems, and more.
Unlike the two cargo compartments, no fire suppressant system is designed into the electronics bay of the Airbus because fire retardant material releases particles that infiltrate the functionality of sensitive electronics and could cause havoc. Instead, a venting system is utilized that theoretically evacuates smoke.
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On a fly-by-wire airplane, controlled by a computer system, a fire could potentially disable the crew’s ability to adequately control the airplane. The pilot’s oxygen system, utilized in the event of a depressurization event, is also in the electronics bay. If fire or extreme heat compromised the hoses connected to the cockpit, pure oxygen has the potential to ignite rapidly and/or explode.
Based on the facts conveyed so far, we can speculate that the faults transmitted by ACARS occurred as a result of electronic circuitry nearest the source of the overheat/fire being affected first. And then at some point, everything in the electronics bay could have succumbed to the event. Forward lavatory smoke would certainly be indicative of a fire or overheat condition coming from below the floor where the electronics bay is located.
It is also plausible that the first fault indication, the copilot’s side window having an anti-ice heating issue, may have resulted in a catastrophic failure that involved a cracked interior pane caused by a fire in the heating element sandwiched in-between the glass. A pilot’s immediate reaction, other than to flinch, is to shut off the power to the offending window. And then, if a fire were evident, someone would have used the portable, cockpit Halon fire-extinguishing bottle.
Although cockpit window cracking can be an alarming and spectacular event, seldom is the situation serious enough to completely compromise the integrity of the offending window: There are two thick panes of glass. Something else would have to have occurred for the pilots to lose complete control of the airplane.
Is a terrorism-planted explosive device still a possibility? Sure. But this new information makes it less likely. Regardless, where there is smoke, there is high probability that there is fire.