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Portable Electronic Devices

This is not a story about performance enhancing drugs nor is it about the newest animated character coming from the house of the mouse even though the topic contains names like Bluetooth and WiFi joined by a cast of celebrities including, iPod, iPad, and even iPaq. So just what is a PED and how does it impact life in our world?

The portable electronic device (PED) has evolved from a noteworthy event in 1948. Bell Laboratories publicly announced the creation of a gadget known as the “Transistor.” The intent was to enable amplification thus making bulky and fragile vacuum tubes obsolete. What followed in the next six years impacted how we listen to music and communicate through the airwaves. The “Transistor Radio” was arguably the first PED with a worldwide distribution. To those not “in tune” it was every bit as annoying in public as the modern cell phone.

Sophisticated electronics have become a reality for today’s aircraft technician. Even our tools have evolved. I find myself as dependent on the ability to connect a laptop to an aircraft as being able to figure out where best to plug in my multimeter. Understanding how to obtain and combine analog and digital information provides an effective means of solving difficult problems.

The use of a PED like most everything else found on an aircraft is regulated. In the United States, Federal Aviation Regulation (FAR) 91.21 provides guidance and lists approved equipment. It stipulates: no person may operate any portable electronic device on a civil aircraft when operated by an air carrier or any time the aircraft is operated under instrument flight rules (IFR). There are certain exceptions which include: portable voice recorders, hearing aids, heart pacemakers, electric shavers along with any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication systems.

Incident and accident reports

Recent incident and accident reports have revealed flight crews using PEDs, including laptop computers and mobile telephones, for activities unrelated to the duties and responsibilities required for a flight. In one widely publicized instance, two airline pilots were using their laptop computers during cruise and lost situational awareness, leading to a 150-mile fly-by of the destination. In another case a pilot was texting after the aircraft pushed back from the gate and missed relevant ground control communications. During an FAA check ride a crewmember’s mobile phone was overheard ringing during the takeoff roll.

It is a pilot’s responsibility to guard against distractions on the flight deck. Technology continues to advance and provides our industry with new tools to assist crews in accomplishing their jobs. For instance, electronic flight bags (EFB) (both installed and portable) and high-speed data transfer units are two of the more recent and increasingly common devices available. For the traveling public, PEDs are an established fact of life particularly in the highly mobile air transportation industry. While PEDs can be valuable tools in aviation operations, crewmembers cannot permit the potential distractions and should continue focusing on duties and responsibilities related to the flight. Regulations regarding sterile flight decks prohibit crewmembers from participating in activities not related to the safe operation of the aircraft.

Flight departments should create a safety culture that clearly establishes guidance, expectations, and requirements to control cockpit distractions, including use of PEDs.

Stay connected

The ability to stay connected while flying has created numerous challenges for those of us involved in keeping the systems functioning. Information specialists find it challenging enough maintaining the data stream to a group of computers in an office environment. Couple these challenges to those found in modern high-speed aircraft and most information technicians throw up their hands as the traditional multi-conductor data cable is not an option in this environment.

Radio waves originating from either space based or ground stations must be in range of the aircraft transceivers for a connection to be initiated and once completed the traditional monthly bill from the phone company won’t come close to covering the connection costs.

An aircraft cabin is a rather fragile environment and a majority of WiFi routers operating here are reduced wattage from those found in the home or office. This can, in fact, be limited by the airworthiness documentation approving the system.

Many factors can impact the successful use of PEDs in a wireless aircraft. The signal is based on a standard WiFi protocol known as the 802.11 standard and uses 2.4 gigahertz as the operating frequency. Not all WiFi compliant devices have the same sensitivity which means some types of PED demand more of the signal than others to function and can reduce the signal for other consumers. Also, the more users streaming data will cause a slow down of the network as the data stream flow can be compared to a pipe and once capacity is reached the stream backs up.

Bluetooth equipment has been confirmed to raise havoc on 802.11 networks as it shares the 2.4 gigahertz airwaves. As Bluetooth utilizes a different data protocol the signal can confuse the 802.11 system bringing data flow to a crawl or even cause a shutdown of equipment. Crews using remote Bluetooth GPS antennas with an IPad have been suspect in terminating cabin Internet activities.

It may be hard to perceive a microwave oven as a portable electronic device but in some instances they do find their way onto aircraft. Microwave energy can be another killer of WiFi and any installation should be tested to ensure an acceptable coexistence.

Interference and the FCC

Cell phones (and other intentional transmitters) differ from most PEDs in that they send signals strong enough to be received at a far distance. Since 1991, the Federal Communications Commission (FCC) has banned the inflight use of 800 MHz cell phones. This is primarily a result of potential interference with ground networks.

The ban requires that in addition to the FAA testing proving no interference with aircraft systems, an operator would also need to apply for an exemption to the FCC before it could allow cell phone use inflight. Even if the FCC ever rescinds its ban, FAA regulations would still apply, and any installed equipment would be subject to FAA certification. The air carrier would have to show that the use of a particular model phone won’t interfere with the navigation and communications systems of the particular type of aircraft on which it will be used.

Airlines often let passengers use newer-model cell phones in what’s called “airplane mode,” disabling the transmit function. This capability allows users to take advantage of other functions. FAA guidance does permit airline passengers to make cell phone calls once the aircraft has landed.

WiFi and frequency analyzers are readily available and can be found in many forms varying from expensive and complex testers to free applications for an Android. Interference can come from a variety of locations including other PEDS, aircraft wiring, and other electronic components. A sweep of an aircraft cabin using a frequency analyzer is a good first step in preventing issues with portable electronics.

The impact of a PED on an operating aircraft has not as yet been fully explored; but, it is still quite probable some impact will occur sooner or later. This may be due in part to frustration of the PED owner with the challenges of staying connected. I just hope the impact does not result from a throwing arm. AMT


Jim Sparks has been in aviation for 30 years and is a licensed A&P. He is the manager of aviation maintenance for a private company with a fleet including light single engine aircraft, helicopters, and several types of business jets. He can be reached at sparks-jim@sbcglobal.net.