A complete mystery surrounds the cause of the probable crash of Air France flight 447.

The first hint of what could have caused the crash came from Air France officials, who spoke of a “lightning strike”. According to Air France's chief executive, Pierre-Henry Gourgeon, the aircraft had sent "a succession of a dozen technical messages" saying that "several electrical systems had broken down", causing electrical and pressurization failures.

But lightning strikes are “commonplace” in today’s airline flights, said aviation expert Pierre Condon, a former editor of French aviation magazine Air & Cosmos.

By Gulliver CRAGG Experts say modern aircraft are designed to withstand lightning bolts.

Modern aluminium- or composite-bodied airplanes are designed to conduct lightning around the body of the plane, leaving the internal systems — and passengers — completely untouched.

At worst, Condon said, lightning can cause the plane to temporarily lose its way because of loss of certain navigational systems. “But that’s all,” he said.

There are other factors. The area in which the Airbus A330-200 disappeared is known meteorologically as the “Intertropical Convergence Zone”. The ITCZ is a moving region near the equator where winds from the northern and southern hemispheres clash violently in storms.

This weather phenomenon is also hindering the search for the missing plane.

By Owen FAIRCLOUGH The location of the plane's disappearance and a unique weather phenomenon are hindering the search effort.

A French crewman searching for the AF 447 said the area has “weather patterns that are dangerous for flying”.

“That means we've only been able to do a very basic search,” he continued.

Search operations are usually conducted very rigorously in mapped-out grid patterns.

Modern aircraft such as the Airbus A330-200 are designed with numerous fail-safes and complete, redundant back-up systems.

Condon explains that “there are complete back-up systems”, including a small ram-air propeller that descends and “runs a little generator giving a minimal current to control the plane and communicate”.

“There are also back up batteries and other systems”. The only way the plane could have crashed, he says, is if none of this worked. He speculates that a combination of events could have caused explosive decompression in the cabin, leading to serious “mechanical failure”.

Black box recovery

The only way to know what really happened to the plane is to find the aircraft’s so-called “black box”, which would contain critical data from the flight. The box, as Jean Louis Borloo, France's environment and transport minister says, “emits signals for thirty days”.

And the Atlantic Ocean has an average depth of 3600m – far deeper than most divers and submersibles can explore. Borloo continues to say that “the ocean bottom reaches three to six thousand metres with strong currents.”

US satellite technology might be needed to help recover the boxes, if it is at all possible. This morning, US President Barack Obama agreed to make all means available to help in the search.

Still, Condon doubts that the boxes will be recovered. “Unimportant debris will be found”. But the boxes might now be at the bottom of the ocean.