By: Richard Wescott: http://www.bbc.com/news/world-middle-east-36349096

I’ve just spoken to a man who has been a pilot for forty-six years, flew the Airbus A320 for six years and has spent the past eleven years investigating fires on planes. Captain John Cox, a fellow at the Royal Aeronautical Society, told me the Egyptair facts are “confusing”. IF the timings we have are right (they are still not officially confirmed), there were 3 minutes of smoke and heat warnings, followed by 4 minutes of powered flight without warnings, followed by a 2 minute fall. “For a fire, that’s a very short period of time. For an explosive event (like a bomb) that’s a very long period of time”, he says. “It’s got me and many other experts scratching their heads. There is an answer, but it’s not clear yet”. John has some sobering statistics. Every year, there are around 900 to 1,200 smoke related incidents on aircraft in the U.S. If you double that number you’ll get a rough, global figure. The vast majority end perfectly safely, but fires have brought down planes. “It’s shockingly regular…and along with drones, it’s the only part of aviation that’s getting more dangerous”. John puts the rise down to two things. An increase in the number of flights. And a huge rise in people taking lithium batteries on board. One estimate says that an airliner carrying 100 people could have 500 lithium batteries in the cabin. In cameras, laptops, tablet computers, phones, e-readers etc. He says crushed batteries are increasingly problematic. “Maybe someone falls asleep. Their tablet computer or phone slips down the side of the chair. They move the seat and accidentally crush the battery.” Potentially, that could start a fire. To be clear, if you buy lithium batteries from a respectable company, they are thoroughly tested and safe, with a one in ten million failure rate. But John says there could be 3.5 billion batteries taken on aircraft throughout a year. It only takes one to go wrong, and they pack a hell of a punch. Look at my report from 2014. And then there are the “grey market” batteries and chargers some people buy on the cheap. They may well not have been safety tested at all. Modern aircraft have smoke detectors, but the only automatic extinguishers are in the cargo bay. Otherwise, it’s down to crew members using a hand-held fire extinguisher. There’s one in the bin of each toilet, for example. A recent paper, co-written by John, says experience shows that many fires start in “inaccessible locations”. Places that crew may not be able to reach. He also made the point that the US regulator, the FAA recently said you can never eradicate all sources of ignition on an aircraft. John used to fly the A320 and says it’s a wonderful aircraft. He’s never heard of a major fire in the front right part of the plane. And it’s been flying in various forms since the late 1980s. Many airlines also now train their staff in how to cope with a lithium battery fire. I want to stress this again. We DO NOT KNOW what caused the Egyptair airliner to come down. It could be an accident. It could be more sinister. But fires on aircraft are an issue and John is calling on the industry to do more to tackle it.