Australia's Regional Express airline has confirmed reports that an iPhone 4 handset spontaneously combusted aboard one of its flights, sparking fears that Apple may once again be suffering from a bad batch of batteries.

Passengers aboard Regional Express flight ZL319 from Lismore to Sydney were shocked - although probably not half as much as the person to whom the iPhone in question belonged - when the cabin filled with "a significant amount of dense smoke, accompanied by a red glow."

The incident, which thankfully didn't result in any injury, sounds like a classic lithium fire - typically caused by a faulty charge circuit or badly manufactured battery.

"In accordance with company standard safety procedures, the Flight Attendant carried out
recovery actions immediately and the red glow was extinguished successfully," the airline reports in a release regarding the incident. "All passengers and crew on board were unharmed."

The handset in question has been passed to the Australian Transport Safety Bureau for analysis, with Apple's local techies likely to find themselves drafted in to find the root cause of the apparent combustion.

If the flaw does turn out to be the result of a batch of flawed batteries, it wouldn't be the first time: the company has recently recalled its first-generation iPod Nano devices over a similar issue.