Boeing conducts broad avionics review after Wi-Fi interference

Boeing’s investigation into why in-flight connectivity interfered with Honeywell’s Phase 3 Display Units (DU) during electro magnetic interference (EPI) testing is not merely limited to those particular Honeywell parts.

The US airframer, which has offered the Phase 3 DUs on aircraft since July 2009, is currently mired in the laborious process of determining whether any other airplane part numbers have the same issue, RWG can reveal.

There are three categories of systems being studied – critical, essential and nonessential required. Boeing is reviewing these systems to ensure they are not susceptible to Wi-Fi or cellular devices.

There are hundreds of systems that must be studied, and Boeing is using RTCA DO-307 – which covers Aircraft Design and Certification for Portable Electronic Device (PED) Tolerance – as guidance.

When a manufacturer goes through qual testing in the lab for RTCA DO-307 (as outlined in the FAA’s advisory circular AC-20-164), it accounts for both the frequency and energy field value at levels well beyond what a cell phone or Wi-Fi would produce if its near that equipment.

The value covers a range between 100 MHz to 8 GHz. To put that into perspective, Wi-Fi operates at 2.4 GHz or 5 GHz and cell phones operates as low as 460 MHz and as high as 2.17 GHz. So yes, the levels tested far exceed all normal scenarios, but for good reason. Who wants people with malicious intent (oh, say, terrorists) to take RF aim at the cockpit? Uh, nobody, except the terrorists.

If the equipment passes muster, it is considered to be T-PED (tranmissing portable electronic device) tolerant, and that’s what Boeing and others are working towards.

If through its review Boeing discovers additional anomalies, it will be forced to further delay linefitting its aircraft with in-flight connectivity systems, a move that would have the biggest impact on Panasonic Avionics and partner AeroMobile, which fought long and hard to achieve linefit status for the latter firm’s eXPhone in-flight mobile connectivity solution. (Side note: I find it rather fascinating that some people downplay such deferrals as ‘no big deal’. These are expensive systems, which are ordered well in advance of delivery. Let me assure you that it is in fact a ‘very big deal’ to the operators that have paid for these options.)

Already, the discovery during EMI testing for Aircell’s Gogo STC on Boeing 737NG aircraft that Phase 3 DUs are susceptible to “blanking” has resulted in Boeing’s decision to defer since last fall  eXPhone linefit installs on Boeing 777s. Carriers impacted by the deferral include 777 customers V Australia (which was supposed to take its fifth 777 with eXPhone), Air New Zealand, Emirates, and Turkish Airlines.

Lufthansa, incidentally, hopes to have both eXPhone and Panasonic’s in-flight high-speed Internet system eXConnect already installed when it takes delivery of its new Boeing 747-8s. 

Boeing’s deferral of linefit installs of in-flight connectivity systems is unfortunate, but necessary not simply because of the event involving Aircell’s STC, but because interference with Phase 3 DUs has also been simulated in testing with a large number of cells phones going off at the same time (a scenario that is also against all operating instructions and procedures).

Some 90 Emirates aircraft are installed with eXPhone – allowing passengers to make and receive voice calls and text messages – and the carrier has not ever experienced issues with interference with avionics. But Emirates does not allow cell phones to be switched on in the cockpit and it’s my understanding that EASA is content for Emirates to place a placard in the cockpit saying just that (just as 737NG operators with Gogo must do as a condition for installing Gogo).

If the interference problem detected with Honeywell Phase 3 DUs on Boeing aircraft is indeed limited to Phase 3 DUs, there is light at the end of the tunnel for eXPhone customers.

Depending upon who you talk to, a Service Bulletin from Boeing could drop as early as next month and the issue could be cleared up by June or as late as the fourth quarter. After all, Boeing is now building brand new equipment like the 777 with the more stringent requirements in place (based on lessons learned through STC). With a new aircraft, it’s far easier to ensure all systems are up to snuff.

At this juncture it would appear that the problems are being discovered on older aircraft with their many mods and STCs.

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