French investigators unsure of Air France 447 speed as plane hits storm over Atlantic

Various arguments have been presented as to why Air France 447 was lost at sea. These include structural breakup, computer failure, sabotage, electrical failure, and an electrical fire. What has not been put forth as a possible explanation is unstoppable blinding smoke in the cockpit. I’m not suggesting that smoke in the cockpit is the answer. I’m only advocating that it is a possibility, one not previously offered, and no less plausible an hypothesis than any other. Let’s look at what is known.

Air France received a bomb threat several days before the crash on a different flight at a different airport. The aircraft was inspected but no bomb was found.

At 11 PM local time, the pilot sent a message that the he was flying though strong cumulonimbus thunderstorms. Other reports stated that the vertical speeds were as high as 100 miles per hour. Air France also said that the aircraft’s automatic reporting equipment reported a short circuit.

Ten minutes later, a series of automatic messages indicated that the autopilot had disengaged, stabilizing controls were damaged, and flight systems deteriorated.

At 11:13 p.m. the system that monitors speed, altitude and direction failed. The main flight computer and wing spoilers failed.

11:14 p.m. The final message indicates a loss of cabin pressure and complete system failure.

According to the DailyMail Online, the Spanish newspaper El Mundo reported that a transatlantic airline pilot reported seeing a flash of white light at the same time the Air France flight disappeared. “ ‘Suddenly we saw in the distance a strong, intense flash of white light that took a downward, vertical trajectory and disappeared in six seconds,’ ”

Sabotage, as with an on board bomb, does not always lead to destruction of the aircraft. In the case of Swissair 330, a bomb exploded on board. The aircraft remained flyable. The pilot attempted to land but could not see due to the smoke in the cockpit. His final sentences were that he could not see to land. His last words were “good-by everybody.” Similar events happened on at least two other aircraft, an Air Cubaña DC-8 and an Air Kuwaiti 737.

Short circuits inevitably lead to wire fires. In aircraft fires the aphorism, “where there’s smoke there’s fire” can as easily be re-stated as, “where there’s fire, there’s smoke.” Wire fires are notorious for generating copious amounts of smoke.

On average, there is one unscheduled or emergency landing in North America daily. Most aircraft land without incident. But In July 2007, a NASCAR corporate twin-engine aircraft crashed. It experienced a short circuit. The wire insulation burned and that led to a cry of “smoke in the cockpit.” The aircraft crashed two minutes later. A short circuit lead to the fire and smoke in the crash of Swissair 111. It’s crash, like the crash of ValuJet 592 that preceded it, began with the cry “smoke in the cockpit.” These three examples and many others can be found in a 16-page report listing aircraft in which smoke was a cause or a factor in aircraft incidents and accidents. (See: http://www.smokeinthecockpit.com/references/List-of-Some-Smoke-Related-Accidents.pdf )

Electrical failures can lead to blinding smoke in the cockpit. Contrary to a common perception, pilots cannot see when unstoppable blinding smoke enters the cockpit. Air France 447 signaled that it was loosing cabin pressure. When smoke invades the cockpit, the Federal Aviation Administration recommends that pilots depressurize the aircraft to force the smoke out. If the smoke were a one-time event, this procedure would likely work. However, when the smoke is continuous, depressurization cannot help. The pressure on the outside and inside of the cabin would be equalized. Continuous smoke would build up, blinding the pilots.

Let me reiterate. I am not stating that continuous blinding smoke brought down Air France flight 447. I am saying that continuous unstoppable blinding smoke in the cockpit is an equally worthy hypothesis to consider. For those interested in more information on the subject, you might want to read Air Safety Week’s overview of the unsafe condition of smoke in the cockpit: http://www.smokeinthecockpit.com/references/Air-Safety-Week-Smoke.pdf

You can also read a recent (May 21st) U.S. House of Representative amendment to the FAA Reauthorization Bill (http://www.smokeinthecockpit.com/references/GAO-Amendment.pdf) that requires the Government Accountability Office (GAO) to study the unsafe condition of unstoppable blinding smoke in the cockpit. For an in-depth article on unstoppable blinding smoke in the cockpit, see —
http://www.smokeinthecockpit.com/references/Blinding-Smoke.pdf

James P. Stevenson
Former Assistant Managing Editor
Air Safety Week