Regulatory considerations
for wireless aircraft
systems
April 17, 2007
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This presentation will give an overview of
regulatory considerations in
broadband wireless system design and
installation onboard commercial
aircraft. Alternative technologies may offer
solutions which deliver the
promise of an internet in the sky.
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Introduction
•Overview to the Wireless Interference Issues
•History of PEDs on Commercial Aircraft
•Past Regulatory Reviews & Findings
•Types of Potential Interference
•Theoretical & Practical
•Incident Reports & Experience
•Industry & Regulatory Activities
•Near-Term & Long-Term Outlook
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History of Wireless Interference Issues - Concern
Over PEDs on Aircraft Is Not New
1963 – RTCA SC-88, Report DO-119 - Dealt with
FM Radio Receivers Resulted in FAR 91.19
controlled use of PEDs. Recommended
prohibiting radios in flight
1988 – RTCA SC-156, Report DO-199 - Concluded
PED EMI Exists but Is Low - Recommended FAA
Advisory Circular for PEDs - Recommended FCC
change classification for PED RF output
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History of Wireless Interference Issues - Concern
Over PEDs on Aircraft Is Not New
1996 – RTCA-177, Report DO-233 - Improved
Aircraft Path Loss Factor Measurements Changed FAR 91.21 to Prohibit PED Use During
Critical Flight Phases
2003 – RTCA SC-202 - Deals with Wireless RF
LANs and Cell Phones (Intentional Tx)
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The U.S. Regulatory Situation
•Dual Regulatory Agencies - Cell Phone and Wireless
Devices on Aircraft are governed by FCC and FAA
Regulations
•The FCC and the FAA Are Coordinating their Activities in
Examining the Use of Wireless Devices Onboard Aircraft.
•The FCC and the FAA Are Seeking Technical Guidance in
the Regulatory Process from Various Organizations –
Notably NASA and RTCA
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Non-FAA Regulatory Developments in the U.S.
FCC Re-Examining Its Ban on Inflight Cell Phone Use
April 6, 2007 – the U.S. FCC is seeking public comment on
whether to permit the airborne operation of "off the shelf"
wireless handsets and other devices under the following
conditions:
a.) The device operates at its lowest power setting under
control of a "pico cell," which is a very small specialized
cellular base station installed onboard the aircraft; and
b.) The operation does not interfere with on-ground users.
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Non-FAA Regulatory Developments (Continued)
Good News for U.S. Passengers Demanding
Voice & Data Connectivity (Parity with European
Passengers)
Opposition by Pilot and Flight Attendant Unions
After FCC Comment Period, FCC Likely to Lift Cell Phone
Ban Under the Conditions:
a.) Only onboard pico-cell technology allowed
b.) Subject to FAA and Airline approval
Good News for AirCell, the U.S. ATG License Holder
•Voice Services Complement to Broadband Service
Offering
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Q: Why Is There A Concern?
A: The Potential for Interference In a Growing Variety
of PEDs Brought Onboard. Note the Range of
Devices for Which Interference Was Reported in a
9/2004 FAA Incident Report Summary Extracted From
NASA-ASRS.
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Q: What Systems Are Affected?
A: Many Different Systems Ranging From Non-Essential to Flight
Critical, Including Navigational, This FAA Chart Depicts
Interference Reports from 1995 to 2002.
30
25
20
15
10
5
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Audio system
Air data
Spoilers
Smoke Detector
NAV
ILS
IRU
Radar Altimeter
COMM
TCAS
FMS
Displays
Autopilot
CDI
LOC
0
VOR
Number of Reports
35
NASA ASRS PED Interference Reports 19952002
Reports per 1000 Airplanes
35.0
30.0
25.0
20.0
15.0
10.0
5.0
0.0
DC9/MD-80
B737
B727
CRJ-600
B757
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B767
F100
What Causes Interference to Avionics from PEDs and Wireless
Devices?
• Coupling of PED emissions with avionics antenna
or components acting as an Antenna.
•Antennas - Leakage Thru Windows, Doors, Seams
•Any Cable (including Seat-to-Seat Cabling)
•Power cables
•Power Supplies
•Poorly Shielded Circuit Board Components
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What Causes Interference to Avionics from PEDs and
Wireless Devices (Continued)?
•What Are the Factors Affecting Coupling?
•Frequency of Emissions
• Fundamental Frequencies (including Harmonic
Frequencies)
• Spurious Frequencies
•Power of Emissions
•Sensitivity of Avionics Device (Shielding Issue)
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Front-Door Coupling
Aircraft Radio Receiver Antenna

Portable electronic
device RF
emissions
Radio receiver
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Emissions
radiated by
portable
electronic
devices can
radiate to aircraft
antennas
through:
− Windows
− Cargo and
passenger
door seams
− Hatches
Back-Door Coupling

RF emissions from
portable electronic
device
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Emissions
radiated by
portable
electronic
devices can
couple directly
to aircraft
wiring and
avionics
NASA Studies on Cell Phones, PEDs & UWB Devices
Multiple Studies Performed – Bluetooth, 802.11, GSM,
CDMA, GMRS and FRS Radios
Cell Phones – Some Small (But Not Zero) Interference
Detected. On/Off Triggered Highest Spurious Emissions
Laptops & PDAs – Emissions Generally Benign But Some
Exceedances of DO160D Category M Emission Limits
For TCAS and DME Bands
GMRS and FRS Radios – Very Noisy – Exceeded Laptops
By As Much As 30dB
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Cabin Wireless LAN (CWLAN) Certification
The FAA Has Issued Several STCs for CWLAN
Systems for:
•Gulfstream & Dassault Falcon 2000
•Bombardier Global Express
•B777-200/300 & B747-400
•A330 & A340
•B757
•B737
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Ground Test & Flight Test Methodologies
•Conduct EMI Assessment to Determine if EMI
Flight Test Is Required. If Required (Likely)
•Perform a front-door and back-door transmission
test to Validate intentional system transmission
levels.
•Identify Average and Maximum Number of PEDs
in Use on Aircraft and Associated Operational and
Failure Mode Power Levels.
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Ground Test & Flight Test Methodologies
(Continued)
•All Frequency Bands Used by the CWLAN
System Need to Be Evaluated
•Aircraft Location Tests Required from various
locations in the cabin where PED usage is
expected (galley, passenger aisles, etc.).
• Verify CWLAN System and PED equipment
meets the current edition of RTCA/DO-160E
section 21, Category M, emission levels.
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What Should an Airline or System/Component
Manufacturer Do to Prevent Wireless Interference?
5 Step Approach
•
•
•
•
•
Ensure That All System Components Pass DO-160E,
Category M
Have Experienced Electrical or Systems DER Review
The Aircraft Installation Plan for Potential EMI Issues
Make Sure Aircraft Wiring Diagram and Electrical
Load Analysis are Up-To-Date (Verify Current AC
Configuration)
Consider Existing Aircraft Antennae Wire Routing
Careful Consideration for Component Installation
Location for Potential EMI Issue with Antennas
or Avionics.
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Summary
The FAA Recognizes There Is A Small Risk to
Sensitive Radio systems from PEDs.
Intentional Transmitters May Interfere With
Some Aircraft Systems That Are Not Qualified to
HIRF Requirements.
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Special Thanks To:
Rolfe Goedecke- Airbus Industrie
Kiko Brenneisen- FAA DER & DAR, Aero Certification
Roger Modeen, FAA DER, Boeing (retired)
Kreg Doerr – Aero Certification
Rich Salter – Lumexis, WAEA TC
Ioan Leuca, Ph.D. – formerly Connexion By Boeing
Bill Straus, Ph.D. – NASA/DOT
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References
“In-Flight Radio Frequency Spectrum Measurements of Commercial Aircraft
Cabins,” DOT/FAA/AR-06/41 Office of Aviation Research and Development
Washington, DC 20591, Bill Straus, Ph.D. and M. Granger Morgan, Ph.D.
“Recent Developments in Aircraft Wireless Networks,” Obi Orjih, Washington
University, May 9, 2006
“Ultrawideband Electromagnetic Interference To Aircraft Radios,” Ely, Jay (NASA);
Fuller (Eagle Wings Inc.); Shaver, Timothy (United Airlines)
“Electromagnetic Interference Assessment of CDMA and GSM Wireless Phones To
Aircraft Navigation Radios,” Ely, Jay (NASA), Nguyen, Truong (NASA), Koppen,
Sandra (Lockheed Martin), Salud, Theresa (Lockheed Martin)
“Guidance on Allowing Transmitting Portable Electronic Devices (T-PEDs) on
Aircraft,” RTCA DO-294, December 13, 2006
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