By Graham K. Rogers

Back in March I wrote in a Cassandra column about an iPhone 5 that had reportedly spontaneously combusted. The report by Exponent has been sent to the NBTC and, as I predicted back in March, there was much more to this than was apparent back then. Instead of a defective product from Apple, this appears to have been caused by another unauthorised repair.

The user was making a phone call (about 30 seconds), felt heat and saw smoke. He threw it to the floor and it exploded. It is not clear if the exploding was due to the impact or the heat event so I had a closer look at the photographs on the site and watched the link to the uncritical MCOT report which is now on YouTube.

As I wrote then, the main area of heat appears to be round the home button, which is beside the Lightning port. The bottom of the lithium-ion battery is just above this, as can be seen from teardown images on iFixit. The report does not tell us if the phone was being charged at the time or if there were any other circumstances. Spontaneous combustion happens in rare circumstances (haystacks in rural England, for example) so the idea of instant heat being generated in 30 seconds, that leads to combustion, suggests to me that there may be something else involved.

The MCOT clip has some more visible information. The iPhone appears to have a screen protector and there have been problems with some of the cheaper ones. There is also a similar plastic screen on the back of the phone. However, the glass has been pushed away from the body of the iPhone which can happen when a battery expands (usually over some time), although the main area of expansion is at the bottom where the battery does not extend. There are no obvious heat marks round the Lightning port.

One other thing we do not know is what version of iOS was being used or what apps were installed. I would like clarification concerning this, especially as many Thai users jailbreak their phones as a matter of course and then install apps that have not been checked by Apple.

Whatever the answers, I wrote then, it is important that Apple examine the phone. If there is a battery problem (or any other problem for that matter) with the phone, they need to have it fixed and any changes to customer installations made as soon as possible. If there are other causes, such as that unauthorised repair that an Australian have made to his iPhone that caused it to catch fire, then that too we need to know. As it is, a suggestion hangs in the air that the phone is not safe: that needs confirming one way or another.

The phone was retrieved by the NBTC and, at Apple's suggestion, was sent to Exponent, an independent testing service. As the Bangkok Post now reports, the explosion "was caused by a small screw found stuck under the device's battery tray." In addition, the presence of "the screw was a mystery, since it was not one of the iPhone 5's orginal parts. It penetrated into the phone's battery and caused a short circuit, leading to the explosion."

The most damning part of the report however, is in the words, the investigation "also found pentagram screws on the phone's outer case were not in their original positions. Investigators concluded the back cover of the device had already been opened or removed by a third party, using tools not approved and required by the Apple warranty."

As I predicted back in March, there was much more to this than met the eye and the event was similar (almost identical) to one in which an iPhone on an Australian plane similarly self-combusted.

One would expect that the owner who made the complaint to the police, Suwicha Uasomsaksakul, will be further questioned about the phone as well as AIS from whom he claimed to have bought it. We also hope that the reporters at MCOT will be hard at work preparing a retraction of the original sensationalism, or at least an update.

Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand where he is also Assistant Dean. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs.