Apple iPhone suspected of interfering with airline equipment in 2011 incident

The compasses on the flight were behaving abnormally, sending the plane several miles off-course, according to a report published Wednesday by Bloomberg. But the systems apparently returned to normal after a flight attendant had a passenger in row 9 turn off their iPhone.

An unidentified co-pilot who spoke to NASA's Aviation Safety Reporting System suggested it was likely the iPhone caused interference with the plane's systems, as the timing of the phone being turned off coincided with when the navigational issues were resolved.

The incident is one of dozens of episodes where airline pilots, mechanics or other personnel believe that passenger electronics may have interfered with airplane systems. However, some major carriers such as Delta still support the relaxing of rules on use of personal electronics under 10,000 feet, noting that there is no way of verifying with certainty that those devices are actually the cause of any interference.

The Federal Aviation Administration has been leaning toward relaxing its current rules, which prohibit the use of most electronic devices — including Apple's iPhone, iPad and iPods — while the plane is under 10,000 feet. But proposed rule changes by the FAA have been held up by technicalities, and the desire to develop a concise, future-proof set of regulations.

The FAA has found itself under considerable pressure to relax the rules that require passengers to power down their devices prior to takeoffs and landings. It hopes to announce a rule change by the end of the year.

Apple's iOS devices include an "airplane mode" feature that turns off all of the wireless radios inside the hardware. But the term "airplane mode" can mean different things across different devices, making it more difficult for the FAA to adopt a standard that can apply to a range of devices.

Modern wireless interference are believed to be associated mostly with cellular radios. That's why airlines that use the iPad as an electronic flight bag do not use cellular-capable versions of Apple's touchscreen tablet.