WIRELESS ABOARD,
WHY ALL THE FUSS?
Douglas J. Hughes, Full Member
International Society of Air Safety
Investigators
© 2011 Douglas J. Hughes
DOUGLAS J. HUGHES
Doug Hughes was an Electromagnetic Environmental
Effects (E3) professional his entire 42-year career, starting
at McDonnell Aircraft in St. Louis after graduation from
the Missouri School of Mines and Metallurgy (Rolla) in
1963 with a degree in Electrical Engineering. He moved to
IIT Research Institute in Annapolis in 1968 to work on the
DoD ECAC support contract. His graduate
Communications Theory degree is from The George
Washington University. He retired in 2005 and moved to
Ann Arbor to be near family.
Mr. Hughes' experience includes database and analysis
model development, sponsor-funded project analysis and
test support, cosite analysis, equipment spectrum
certification, management, and serving as a technical
advisor. He is a full member of the International Society of
Air Safety Investigators (ISASI) with 31 studies or
investigations. All involved aircraft E3, including the
Forrestal fire, two RTCA studies of portable electronics
aboard, the USAF IFO 21 CT-43A accident in Croatia, RQ-4A
AV-2 GLOBAL HAWK, and TWA 800. He continues ISASI
activity in retirement by participating in the Unmanned
Aircraft Systems Working Group. Lessons learned from
the RTCA and a few other safety investigations will be
described this evening.
PRESENTATION OUTLINE
• Wireless Aboard Aircraft
– Commercial
– General Aviation
IF TIME AND INTEREST ALLOWS
• Aircraft Electromagnetic Environmental
Effects (E3)
• Example Accident/Safety Investigations
Involving E3
RECENT ABC NEWS COVERAGE
Right click photo to open hyperlink
WIRELESS-ABOARD ISSUES
• Economic
• FAR 91.21
• Public Accustomed to Constant Access to
Information – Web and Telephone
• Electronics Development
– Personal Electronics – Rapid
– Avionics – Slow
– Aircraft – Generational, but Economic Based
• Human Factors
ISSUES - CONTINUED
• Network Access
– Extensive
– National Differences - Regulatory
– Over Ocean
• One or More Devices Radiating on Every
Commercial Flight
• Technical
– Cellular Telephone Signal Formats
– Delay Equalization
– Pico Cellular Controller For Use Aboard
• General Aviation
• Electromagnetic Interference (EMI)
MANY STUDIES OVER THE YEARS
• Over Twenty Different Formal Studies
• EMI Issues Addressed by NASA/Langley, US
Department of Defense, FAA, Aircraft
Manufacturers, Universities, etc.
• Consensus Groups
– RTCA based in the USA with international
participation
– European Organization for Civil Aviation
Equipment (EUROCAE) with USA participation
THE RTCA SPECIAL COMMITTEES
• SC-88
– Radiating Oscillators in FM radios vs VOR receivers
– DO-119 of April 12, 1963
• SC-156
– Notebook PCs – Wayne Greene of BYTE Magazine
– DO-199 of September 16, 1988
• SC-177
– Cellular Telephones – Episode One
– DO-233 of August 18, 1999
• SC-202
– Cellular Telephones - Episode Two and WiFi
– DO-294C and DO-307 of December 16, 2008
AIR CREW REPORTS
• NASA’s Air Safety Reporting System
(ASRS) contains hundreds of crew
reports of EMI from passenger portable
electronic devices (PEDs).
• Both commercial and general aviation
crews report EMI.
• Military crews have also reported EMI
from PEDs aboard.
• The crew unions (ALPA, APA, AFA, etc.)
are concerned about aircraft safety wrt
PEDs.
AIRCRAFT MANUFACTURER CONCERNS
THE PROBLEM WITH PEDs
MAXIMUM VALUES
Measured PEDs
L e v e l, d B u V /m
WB Switching Power Supplies
95
NB Local Oscillators
and Video Display Sweeps
and Clocks
85
75
65
55
45
35
25
1E-2
1E-1
1E0
1E1
1E2
Frequency, MHz
1E3
1E4
FRONT- AND BACK-DOOR EMI
(See Figure 5-2 of RTCA DO-294)
Front-Door Coupling
• PED Undesired Emissions Coupled Through Fuselage Windows
and Door Seams to Radio, Navigation, and Radar Antennas
• 75 MHz: Marker Beacons
•
•
•
•
•
•
•
•
•
•
108-136 MHz: ILS Localizer, VDT, VOR, VHF Comm, VDL
329-335 MHz: ILS Glide Slope
962-1215 MHz: DME (Military TACAN)
982 MHz: ADS-B UAT
1030, 1090 MHz: ATC & TCAS
1530-1610 MHz: Satellite Comm
1575.42 MHz: GPS
4200-4400 MHz: Radar Altimeter
5030-5090 MHz: Microwave Landing System
5350-5470, 9300-9500, 15500-15700 MHz: Weather Radar
Back-Door Coupling
• PED Desired Emissions Coupled to Avionics Boxes
• PED Desired Emissions Coupled to Avionics Wiring
PEDs COUPLING ABOARD
Wire bundles run everywhere
behind the fiberglass panels.
Windows become apertures
above 100 MHz.
There are also wire bundles
beneath passengers’ feet
and above their heads.
PROGRESS TO DATE
• FCC Notice Of Proposed Rule Making – Ban on
Cellular Telephone Use in USA Continuing
• Cellular Telephone and WiFi Use Allowed On A
Few Foreign Carriers
• WiFi Allowed For US Carriers After FAA
Approval Via AC 91.21-1B
• A/A and Other Carriers Flying A Few Pico CellEquipped Aircraft – Service Supplied by
GoGo/AirCell
• More To Come Depending On Positive Market
GOGO LOWER USA 48 COVERAGE
From: http://www.gogoinflight.com/jahia/Jahia/site/gogo/customerCare/coveragemap
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