Pilot’s Perspective: Mobile at 35,000 Feet

At one time, mobile phone usage was totally banned on board aircraft, but now, the path is set for airborne use of smartphones and other electronic devices.

Image: Getty

Do mobile phone signals really interfere with navigational flight instruments? The truth is, these signals can have a strong impact on the surroundings. A good example of this is where, if your mobile phone happens to be next to older unshielded radios and there is an incoming call, you can hear a squelchy noise. In that same order, there can be interferences on board a flight caused by strong mobile phone signals, and anything that affects the plane should not be taken lightly. This is especially vital in less than favourable flying conditions such as in bad weather, when a plane relies heavily on various electronic signals to stay locked onto the centre beam of the runway as it approaches for an automatic landing.


Cellular communications may disrupt cockpit equipment and electronic signals. Generally, aircraft electronics are shielded from any unintentional signal interference. Nevertheless, for safety reasons, even the slightest possibility of potential interference with aircraft instruments cannot be dismissed. Although it is impossible to say with absolute certainty that cellular communications have contributed to undesirable incidents, the data also makes it impossible to rule that out completely. Therefore, prohibitions on mobile phone usage in midair is the best course of action for regulatory bodies.


If ever the pilot has cause to suspect erroneous readings on the flight or engine instruments, one of the troubleshooting procedures requires a search to ascertain if any passengers are using a prohibited electronic device in the flight cabin. If a barred device is found to be in use and is switched off, the navigation system usually returns to normal.

This situation actually happened in an incident involving a Boeing 737. During an approach for landing, the pilot noticed that the cockpit instruments were showing an erroneous position for the airplane on; one moment, the flight was on course, and the next, it wasn’t! When the pilot finally sighted the runway, the aircraft was flying too high and was too far north to land. It was eventually discovered that a passenger was using her mobile phone at the time. When the device was switched off, the cockpit instruments returned to normal, and the aircraft landed safely.

Photo: ROKKI


In line with technology advancements and a growing digital-savvy population worldwide, in October 2013, FAA (Federal Aviation Administration) lifted the ban against the use of airborne electronic devices, allowing airlines to “… safely expand passenger use of Portable Electronic Devices (PED) during all phases of flight…”. However, airborne calls using mobile phones remain prohibited.

Since this change in policy, some airlines have installed technologies to permit mobile phones to be connected onboard. For instance, in March 2008, Emirates began allowing inflight voice calls on certain commercial airline flights. And as of August 2014, Qantas Airways permits mobile phones (and other portable electronic devices weighing less than 1kg) to be switched on for the entire flight, provided the devices are in flight mode.


Although use of mobile phones is still prohibited on board AirAsia aircraft, guests have access to cellular communications via the airline’s onboard ROKKI Wi-Fi service. AirAsia flights that offer this service have the universal ‘Wi-Fi Available’ icon prominently displayed on the inner side of the aircraft’s doors. Rest assured, the service was only implemented following approval from the relevant regulatory bodies, namely DCA (Department of Civil Aviation) and MCMC (Malaysian Communications and Multimedia Commission).

With ROKKI, AisAsia’s onboard Wi-Fi portal that features inflight entertainment and cellular connectivity, guests can use their Wi-Fi enabled smartphone or tablet to connect to instant messaging, social media and email, as well as access the airline’s inflight menu, travel guides and other exciting offerings. To get connected on ROKKI, a token is required, which can be purchased by cash from cabin crew or by credit card on the ROKKI portal itself. The onboard Wi-Fi service is only available at an altitude of 10,000ft and above. When the aircraft drops below 10,000ft, or if it is flying within the territories of India, China or Macao, the service automatically turns off.


Some airlines still restrict mobile phone usage for the entire flight. All Chinese airlines for instance, excluding Hong Kong and Macao airlines, strictly enforce this prohibition, and make no exception even if the phone is on flight mode.

Although there is no hard-core evidence to show that mobile phones interfere with flight equipment, it’s infinitely wiser to err on the side of caution. In this regard, airlines do need passengers to adhere to inflight protocol and safety measures. In the meantime, enjoy AirAsia’s ROKKI Wi-Fi in the knowledge that safety is assured as you surf, text and email at 35,000ft!

Captain Lim Khoy Hing is a former AirAsia Airbus A320 and AirAsia X A330/ A340 pilot who also used to fly the Boeing 777. He has logged a total of more than 25,500 flying hours and is now a Simulator Flight Instructor with AirAsia X. In his spare time, he shares his opinion on aviation issues with others. For more air travel and aviation stories, check out his website, ‘Just About Flying’ at

Captain Lim Khoy Hing’s second book Sky Tales (a follow-up to Life in the Skies which won third place in the Reader’s Choice Award at the Malaysia BookFest 2015) and the Mandarin version of Life in the Skies are now available for purchase on board all AirAsia and AirAsia X flights. Pre-book your copy at to enjoy these great collections written by a veteran aviator.

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