Is FAA going above and beyond with interference testing?

Unsubstantiated rumors are circulating that the US FAA may be going above and beyond normal electro magnetic interference (EMI) testing protocol when in-flight connectivity service providers seek supplemental type certification (STC) for their systems on aircraft, and that that is the reason why Honeywell Phase 3 Display Units blanked out during STC testing of Aircell’s Gogo in-flight Internet system on Boeing 737NG aircraft.

The reason for the alleged stepped-up protocol, according to scuttlebutt (i.e. not confirmed) is that regulators are concerned that terrorists would focus an intense amount of RF signals at the cockpit (think a heaping transmitter in the forward lavatory) and bring down an aircraft.

Today, at the ISTAT conference in Scottsdale, Arizona, I asked FAA administrator Randy Babbitt if the agency is quietly bolstering EMI testing standards. Babbitt says there is nothing quiet about FAA’s interest in ensuring appropriate testing is done. But he, like the FAA’s public relations office, does not volunteer specifics.

Wewill decline to comment on the specifics involved in certifying the AircellGogo system,” says a spokesman for the FAA.

The spokesman says that when the FAA  evaluates in-flight WiFi systems, “two of the areas we consider are interference with avionics systems necessary for continued safe flight and landing, and any vulnerability of airplane systems to intentional or accidental electronic emissions outside FCC standards.”

Specifically, when  conducting EMI tests, applicants are required to:

1) Perform an airplane ground test using a portable wireless transmitter emulator.  RTCA/DO-294B defines a test procedure with an emulator consisting of a signal generator, amplifier and transmitting antenna.
2) The emulator antenna should be placed at each location, including the flight deck, in the airplane cabin where the access point antennas are installed, and at locations where WLAN-equipped PEDs may be operated.

3) Monitor all aircraft systems with catastrophic, hazardous, and major failure conditions, and systems required by certification or operating regulations.

4) The test is performed at three separate channels in each general WLAN operating band that will be used in the airplane WLAN installation.

Some industry observers believe avionics should be able to withstand even the most stringent EMI testing. In this instance (involving Gogo), interference with Honeywell Phase 3 DUs “should be known well before Gogo is placed on a 737″, says a source, noting that such discovery should have been made in qual testing or, at least, later when the system was certified for the aircraft.

Boeing has launched a thorough review of part numbers to make sure no other avionics suffer the same issue as the Honeywell Phase 3 avionics.

However, notes an industry source, the very instance of interference between Wi-Fi and avionics is “bad news for the industry as a whole because there are a lot of people pushing for COTS [consumer off-the-shelf] technology to be brought into aircraft, and anything that carries a transmitter means that it’s emitting signals.”

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2 Responses to Is FAA going above and beyond with interference testing?

  1. BW March 16, 2011 at 9:47 am #

    The testing required by DO-294 is indeed different than the usual EMI test performed on the installed system (e.g. Gogo). In fact, it is usually performed prior to the installation. It considers a sort of worst case scenario involving portable devices “going rogue” and transmitting at maximum power.

    The RF levels used for this testing are substantial, and the size of the equipment (signal generators, amplifiers, antennae) required to achieve it would probably not fit in the largest of carry-ons – and would certainly make a trip to most aircraft lavatories interesting. So I’m not really buying the anti-terrorism angle.

    The diversity of wireless technologies means a new round of testing for each one. For instance, an aircraft with a wi-fi system would need new testing for operational approval of cellular devices, since new frequencies are being considered.

  2. Jack Stiekema March 21, 2011 at 1:49 am #

    There is an industry standard which equipment has to withstand, like 10V/m or even 100V/m.
    Running around with transmitters, amplifiers and antenna’s change the scientific and proven methods into panic behavior and make all needed official tests unimportant and susceptible to negligence.