CEPT
ECC
CEPT/ECC/RA
Project Team RA6
Luxembourg, 6 - 10 February 2006
RA6(06)04xx
Electronic Communications Committee
Source: ICAO
Subject: Licensing and operation of GSM base stations on
board aircraft
This contribution contains comments of the International Civil Aviation Organization
(ICAO) on the text for a Draft ECC Decision on the harmonised use of airborne GSM
systems in the frequency bands 1710 – 1785 and 1805 – 1880 MHz. The comments
are marked as “ICAO Note”.
ELECTRONIC COMMUNICATIONS COMMITTEE
DRAFT
ECC Decision
of DD MMM 2006
on the harmonised use of airborne GSM systems
in the frequency bands
1710 – 1785 and 1805 – 1880 MHz
(ECC/DEC/(06)**)
EXPLANATORY MEMORANDUM
1
INTRODUCTION
There is increasing demand to use mobile communications from wherever you are
located, including the use of GSM mobile phones on board aircraft. However, to
ensure successful operation of systems which will facilitate this there is a need to
establish a basis for the free circulation and use of such equipment within Europe and
to provide access to the required spectrum.
ICAO Notes:
1)
The free circulation and use of radio equipment on board aircraft for the
purpose of public correspondence is not governed by the provisions of the ICAO
Convention. Such utilization needs to be regulated by the relevant national
authorities.
2)
The regulatory subject of the Draft Decision is ambiguous with respect to
which parts of GSM use on board aircraft are covered under this decision. It is not
totally clear whether it is the intention to cover the use of certain radio frequencies by
a GSM base station (radio frequency license) within the fuselage of an aircraft or to
provide a regulatory framework for the operation of a GSM base stations together
with passenger mobile phones. It needs to be recognized that all sources which may
radiate RF energy (e.g. base station and mobile phones) have the potential to produce
harmful interference to aircraft communication and navigation equipment.
3)
It is assumed that the Draft Decision covers the installation and operation of a
GSM base station on board an aircraft which is registered in a CEPT State. In
addition, the use of the base station is limited to the territory of CEPT States whose
territory is flown over. There are no intentions to use the GSM base station beyond
the boundaries of CEPT States.
2
BACKGROUND
It is a general aim of the Electronic Communications Committee (ECC) to facilitate
the free circulation and use of radio equipment. An objective of this Decision is to
extend the application of this general aim to include the air transportation domain.
ICAO Note:
In this paragraph it is not clear what the air transportation domain
includes. Certainly, it does not include messages for the safety and regularity of
flight; these are solely covered by the ICAO Convention and any additional national
regulation concerning the application of the relevant Annexes of the Chicago
Convention.
The system under consideration in this Decision, (i.e. the equipment necessary to
establish a GSM 1800 MHz pico-cell1system on board an aircraft, “the System”),
together with the spectrum used on board an aircraft, is intended to provide an
interface between the on board GSM handsets and the terrestrial networks providing
the full range of services normally provided on a GSM network. It is important to
ensure that the mobile phones on board the aircraft do not attempt to register with
terrestrial Base Transceiver Stations (“BTS”) and can only register with the on board
System. The link between the on board System and the terrestrial network does not
form part of this Decision. The link will operate in a different frequency range using
satellite links. These satellite links will be operated in accordance with relevant ECC
Decisions. The System will only be operated during certain phases of the flight and
will not be operated while the aircraft is on the ground or during take-off and landing.
ICAO Note:
Why is “the System” not operating during take-off and landing? As
stated above, a significant drawback is that this document covers only the GSM base
station on board an aircraft and not the passenger mobile phones. If for example the
flight crew switches off the base station, then the associated mobile phones loose
connectivity and try to re-connect at the same time to a base station. It should be
noted that when a mobile phone is unable to connect to a base station with its current
power settings, it may further increase its transmit power and as such may even
aggravate the problem of RF interference into avionics. The issue of enforcing a
switch off of the entire GSM operation on board aircraft (e.g. base station and all
mobile phones) during take-off and landing is unclear and may create difficulties for
flight operations.
1
Pico cells are cells, mainly used indoors and in this case within the aircraft hull.
There is a need for a harmonised approach to the System together with its harmonised
use to ensure the provision of an uninterrupted service whilst aircraft cross the borders
of various countries and to reduce the regulatory requirements placed on
administrations, GSM network operators and aircraft operators.
ICAO Note:
The measures indicated above to avoid interference to the GSM
ground networks are noted. These should be accompanied with similar measures to
prevent interference on board aircraft. The absence of such measures may cause
serious problems to aircraft operations.
It will frequently be the case that on any one flight an aircraft will travel through the
airspace of more than one country with the time spent in the airspace of any individual
country being of short duration. An agreed regulatory approach is required to ensure
that the GSM 1800 MHz spectrum utilised by the System can be used in any national
airspace that the aircraft is crossing.
Having regard to: (i)
the provisions of Article 18 of the ITU Radio Regulations;
(ii)
the provisions of Articles 1,30(a) and 33 of the Chicago Convention (1944);
(iii)
the provisions of the International Civil Aviation Organisation General
Assembly Resolution A29-19;
(iv)
the fact that the System will be controlled so as to ensure that there is no
harmful interference with any other system operating outside the aircraft
cabin; and
(v)
the ECC report [WGSE PT7 report on GSM-use on board aircraft]
ICAO Notes:

Re. (i) above:
Art. 18 of the Radio Regulations stipulates, inter alia, that:
“2)
For land mobile stations, including stations consisting only of one or
more receivers, a clause shall be included in the licence, specifically or by
reference, under which the operation of these stations shall be forbidden in
countries other than the country in which the licence is issued, except as may
be provided by special agreement between the governments of the countries
concerned.”
It is the responsibility of the administrations to obtain such an agreement with
regard to “the System”.

Re. (ii) above:
Article 30 of the ICAO Convention stipulates that:
“Aircraft radio equipment
a) Aircraft of each contracting State may, in or over the territory of other
contracting States, carry radio transmitting apparatus only if a license to
install and operate such apparatus has been issued by the appropriate
authorities of the State in which the aircraft is registered. The use of radio
transmitting apparatus in the territory of the contracting State whose territory
is flown over shall be in accordance with the regulations prescribed by that
State.
b) Radio transmitting apparatus may be used only by members of the flight
crew who are provided with a special license for the purpose, issued by the
appropriate authorities of the State in which the aircraft is registered.”
Art. 30 b needs also to be considered when regulating the use of radio
transmitting devices on board aircraft. See also Assembly Resolution A29-19
below.

Re. (iii) above:
The Assembly Resolution A-29-19 “Legal aspects of the global air-ground
communications” covers the use by unlicensed persons of radio transmitting
apparatus installed upon an aircraft where the use is for non-safety related
air-ground radio transmissions. This Resolution covers mainly in-seat
passenger telephone systems, where the transmitting device is installed on
board an aircraft and “operated” by a passenger when making a telephone
call. A GSM base stations which is assumed to be installed upon an aircraft, is
not directly operated by a passenger. Further investigation is necessary to
verify whether GSM mobile phones which are not installed upon an aircraft
and operated by “unlicensed persons” (passengers) are covered under this
Resolution.

Re. (iv)above:
The term “aircraft cabin” is not clear. What are the systems outside the
aircraft cabin? Is there a definition of what constitutes the “aircraft cabin“?
If it is the intention to protect radio and other equipment on board an aircraft,
what are the technical conditions for “the System” to “ensure that there is no
harmful interference with any other system operating outside the aircraft
cabin”. If this provision only refers to the protection of GSM ground networks
then this issue needs to be solved outside aviation.

Re. (v) above:
The ECC Report [WGSE PT7 report on GSM-use on board aircraft] is
believed to only address interference into the GSM system.
For the purposes of this Decision it is considered that the responsibility for the
authorisation of the spectrum utilised on board an aircraft as part of the System should
be that of the country of registration of the aircraft.
ICAO Note: It is understood that the “authorisation” mentioned above covers the
frequency assignment and licensing of GSM base stations installed on board aircraft
only. Such radio license is not made under any ICAO provision.
Airworthiness certification of the System is the separate responsibility of the civil
aviation authorities of the country of registration of the aircraft.
ICAO Note: Article 31 of the Chicago Convention requires that radio equipment on
board shall be covered by a certificate of airworthiness. The process of airworthiness
approval of radio equipment includes requiring the assurance of the correct
functioning of the equipment after its installation in the aircraft, which includes its
compatibility with other on board radio and electronic systems. Prior to its
installation it must have received approval under a national regulation (such as a
Technical Standard Order) issued by a responsible body.
3
REQUIREMENT FOR AN ECC DECISION
There is a need for an ECC Decision to allow for the harmonised use of the System in,
and to permit access to, the GSM 1800 MHz frequency band.
ECC Decision
of DD MMM 2006
on the harmonised use of airborne GSM systems
in the frequency bands
1710 – 1785 and 1805 – 1880 MHz
(ECC/DEC/(06)**)
ICAO Note: As stated before, the scope of the Draft Decision is unclear. “Allow the
use of the System” as stated in Decides 1, must be a joint effort of aviation and radio
regulatory authorities of a State. An ECC decision on that specific subject should be
limited to provisions governing the process of assigning frequencies to GSM base
stations when installed on board aircraft. The installation of such a base station need
to be covered by the certificate of airworthiness.
“ The European Conference of Postal and Telecommunications Administrations,
Considering
a) That the bands 1710 – 1785 and 1805 – 1880 MHz are allocated to the mobile
service on a co-primary basis in the ITU Radio Regulations;
b) That within Europe the bands 1710 – 1785 and 1805 -1880 MHz have been
designated for GSM usage;
c) That it is possible to enable the use of GSM handsets on board an aircraft
during flight by use of the equipment necessary to establish a GSM 1800 MHz
pico-cell system on board an aircraft (“the System”);
ICAO Note: Although the statement on its own is obviously true, it does not reference
to a “safe use” of mobile phones by passengers on board aircraft. ICAO is of the
opinion that this subject needs significant further work. Technical issues regarding
the protection of avionics from mobile phones are currently addressed, inter alia, by
RTCA Special Committee 202. A general statement that mobile phones can safely be
used on board aircraft is currently not supported.
d) That, provided the power levels and frequency bands used are suitably
controlled so that the mobile phones on board an aircraft in flight do not
attempt to register with terrestrial systems and can only register with the on
board System, it is possible to ensure that there is no harmful interference to
aircraft or any other systems operating outside the aircraft;
ICAO Note: In ICAO’s view it has not been demonstrated that harmful interference
will not be caused to aircraft systems (probably this Draft Decision refers to any
equipment on board the aircraft). Interesting to note that if a "pico-cell" interference
problem is identified on board an aircraft and the flight crew tries to solve the issue
by switching off the base station, then all mobile phones will loose connectivity and
try to re-connect at the same to a base station. When a mobile phone is unable to
connect to a base station with its current power settings, it may further increase its
transmit power to a maximum value and as such aggravate the problem.
e) That, as the System will confine the effect of the relevant GSM spectrum
within the aircraft, therefore it will facilitate the efficient use of spectrum;
ICAO Note: The effect on aviation use of spectrum for safety and regulatory purposes
has not been addressed.
f) That, without prejudice to the minimum height requirements set out in the
Annex, administrations may from time to time place additional altitude or
geographic restrictions on the operation of the System over their territory;
g) That for the purposes of this Decision the aircraft cabin space is considered to
be subject to the control of the country of aircraft registry and the System will
only be used within the aircraft;
h) That accordingly responsibility for the authorisation of the GSM spectrum
utilised on board an aircraft as part of such a System is that of the country of
registration of the aircraft, in accordance with that country’s licensing regime;
i) That the use of the relevant frequencies will be authorised by one
administration but those frequencies could also be used within the airspace of
other countries, subject to the regulation of those countries;
j) That the System and its associated components will be subject to airworthiness
certification by the aviation safety authorities;
ICAO Note: The transmitting function of a GSM mobile phone is not addressed even
though these devices may produce harmful interference to on board systems.
k) That the link between the System and its terrestrial gateway does not form part
of this Decision.
l) That, despite measures to ensure interference free operation referred to in
considering d), e), and f), it may remain necessary for administrations to assist
each other with the resolution of reports of interference;
ICAO Note: Where considering d) seem to be the only place where interference to on
board equipment is mentioned, ICAO’s concern is to secure that NO interference will
be caused to essential on board navigation and communication equipment. The
likelihood of interference, as mentioned in l) above is un-acceptable.
m) That the System only provides an airborne electronic communication service,
to mobile devices inside the aircraft.
ICAO Note: Is this “in the aircraft” or” in the cabin”?
n) [That the equipment shall comply with the R&TTE Directive and its article
3(2), which may be demonstrated by compliance with any relevant harmonised
standard or equivalent technical specifications];
ICAO Note: What are these relevant standards or equivalent technical specifications?
o) That this Decision shall not impede EEA member countries from fulfilling
their obligations according to Community laws;
DECIDES
1. That administrations shall allow the use of the System within the frequency
bands 1710 – 1785 and 1805 – 1880 MHz provided that the system operator is
either authorised to use the required spectrum or has been exempted from the
need to be so, in each case by the country of registration of the aircraft and in
accordance with the restrictions referred to in considering (f) and the
requirements set out in the Annex;
ICAO Note:
Decides 1 goes behind the mandate of the ECC. The use the System on
board aircraft needs also approval from aviation authorities of the State of registry
(e.g. certificate of airworthiness). It is suggested that this Draft Decision governs only
the assignment process of frequencies from the bands 1710 – 1785 and 1805 – 1880
MHz to airborne GSM base stations.
2. That operators of the System shall not claim protection from nor shall the
System cause harmful interference to any other system;
ICAO Note: It needs to be recognized that all sources which may radiate RF energy
(e.g. GSM base station and mobile phones) have the potential to produce harmful
interference to aircraft communication and navigation equipment.
3. That this Decision only applies if the System and its associated components
has the appropriate airworthiness certification from the relevant aviation safety
authority;
4. That the System shall comply with the technical and operational requirements
set out in the Annex.
5. That this Decision enters into force on [dd mmm yyyy];
6. That CEPT administrations shall communicate the national measures
implementing this Decision to the ECC Chairman and the Office when the
Decision is nationally implemented.
Note:
Please check the Office web site (www.ero.dk) for the up to date position on
the implementation of this and other ECC Decisions.
ICAO Note: This Decision needs significant further work. Technical issues regarding
the protection of avionics from mobile phone use on board aircraft are currently
addressed, inter alia, by RTCA Special Committee 202. It is suggested that this Draft
Decision governs only the assignment process of frequencies from the bands 1710 –
1785 and 1805 – 1880 MHz to airborne GSM base stations. The use of the System
together with the passenger mobile phones on board aircraft needs to be regulated by
aviation authorities of the State of registry.
This draft Decision is a further step which may result in raising the interference levels
for aeronautical safety communication and navigation.
Annex
Questions:
1. What are the assumptions made as to what constitutes harmful
interference to the terrestrial networks?
2. What are the limiting factors or combination of limiting factors and
values necessary to avoid harmful interference to the terrestrial
networks (assuming a minimum height of 3000 meters)? e.g.:
 The maximum radiated power level of the NCU depending on
the frequency and altitude?
 The maximum radiated power level of aircraft base station
operating in the GSM 1800 band.
 The maximum radiated power level of the aircraft mobile station
operating in the GSM 1800 band.
3. What are the exact frequency bands and systems controlled by the
NCU?
4. What is the minimum average attenuation due to the aircraft required,
in order for the system to work at 3000 meters with and without an
NCU, without causing harmful interference to the terrestrial networks?
5. What is the minimum height , assuming no attenuation due to the
aircraft and with and without NCU, for the system to work without
causing harmful interference to the terrestrial networks?