All sorts of strange things can happen when a plane takes off. Maybe it’s happened to you: an ink pen bursts from the pressure changes and gets ink all over your stuff; an empty water bottle expands on the way up, then goes back to normal on the way down; you fall asleep at cruising altitude and wake up just before landing to find that your ears haven’t popped during the entire descent (trust me, that’s not fun); or maybe your iPhone cracks, glows red, and starts to smoke.

Okay, maybe that last one is pretty rare. But it has actually happened. Back in November passengers on an flight from Lismore to Sydney, Australia were dismayed to find that an iPhone carried by one of their number had begun to glow red and emit dense smoke. The rear panel of the phone even cracked – and lost part of the glass.

At the time, it wasn’t clear what had caused the problem. The iPhone is hardly a perfect device and certainly has its fair share of flaws and glitches, but you can usually trust them not to spontaneously combust in your pocket. Well, ZDNet is reporting that the cause of the malfunction has been revealed. After the incident, the phone was sent to the Australian Transport Safety Bureau for examination. It seems that not long before the incident, the phone’s owner had gotten the iPhone’s screen replaced by an unauthorized third-party. When the replacement was done, a screw from the bottom of the phone, near the dock connector, was not sufficiently tightened. That screw managed to work its way all the way up to the top of the phone and punch through the casing surrounding the battery.

As you might expect, poking something metal through the housing of a battery is not a good thing. In this case it caused a short circuit that in turn cause the phone’s battery to drastically overheat, producing the red glow and the smoke. In the photo you can see an x-ray image of battery compartment and the offending screw.

So it looks like the moral of the story is that if you want repair work done on your iPhone, you’re probably better off to just pony up and have Apple do it. Otherwise your phone could catch fire, apparently.