U.S. Department of Transportation

Federal Aviation Administration

+-------+---------------------------------------+---------+------------+
| Sub   | ACTION: Policy Guidance for           | Date:   | Draft      |
| ject: | Certification of In-seat Power Supply |         |            |
|       | Systems on Title 14 Code of Federal   |         |            |
|       | Regulations, Part 25 Aircraft         |         |            |
+-------+---------------------------------------+---------+------------+
| From: | Manager, Transport Airplane           | Reply   | 01-111-165 |
|       | Directorate, ANM-100                  | to:     |            |
|       |                                       |         | Stephen    |
|       |                                       | Attn.   | Slotte     |
|       |                                       | of:     |            |
|       |                                       |         | ANM-111    |
|       |                                       |         |            |
|       |                                       |         | \(425\)    |
|       |                                       |         | 227-2315   |
+-------+---------------------------------------+---------+------------+
| To:   | SEE DISTRIBUTION                      | Reg     | 25.1301,   |
|       |                                       | ulatory | 25.1309,   |
+-------+---------------------------------------+---------+------------+
|       |                                       | Refe    | 2          |
|       |                                       | rences: | 5.1333(c), |
|       |                                       |         | 25.1351,   |
|       |                                       |         |            |
|       |                                       |         | 25.1       |
|       |                                       |         | 353(a)(b), |
|       |                                       |         |            |
|       |                                       |         | 25.1431,   |
|       |                                       |         | 25.1529    |
+-------+---------------------------------------+---------+------------+

The policy contained in this memorandum has been harmonized between the
FAA and a Joint Aviation Authority (JAA) and industry harmonization
working group. It should be applied to all transport airplane programs
for an acceptable method of compliance with 14 CFR part 25 for in-seat
power supply systems (ISPSS) installations.

**INTRODUCTION**

The following describes conditions that should be met for the approval
of ISPSS which connect aircraft electrical power to passenger provided
carry-on devices. This policy does not cover the approval of the use of
such portable electrical devices (PED's) or any interconnecting means
(adapters, cords etc.) used to power such equipment onboard an aircraft.
This guidance covers the approval of low voltage (nominal 15V DC) and
high voltage (nominal 110V AC, 60 Hz) systems. Nominal output voltages
differing from the typical voltage values specified above may also be
considered for approval using the guidelines specified in this policy.
For guidance on additional criteria to be met for the approval of the
high voltage ISPSS, refer to Paragraphs l), m), and n) of this policy.

This policy is based on the FAA memorandum on the same subject, dated
June 24, 1997, issued by the Transport Airplane Directorate. This policy
was modified from that in a JAA and FAA study group (DFSG#103) and
agreed to on October 5, 1999. Differences from the Draft JAA policy
include: references to FAA, CFR, AC (Advisory Circular) etc., rather
than JAA, JAR (Joint Aviation Requirements), AMJ (Advisory Material
Joint), etc.; the use of American English terminology and some minor
clarification and editorial modifications.

**ISPSS APPROVAL CONDITIONS**

a\. The ISPSS should be designed to provide circuit protection against
system overloads, smoke and fire hazards resulting from intentional or
unintentional system shorts, faults, etc., (e.g., including spilling
liquids in the sockets and children inserting thin metal objects into
the sockets. Ref. 14 CFR, Sections 25.869, 25.1353, 25.1357).

Output power should not be present at the ISPSS socket until the
portable electrical device (PED) connector is correctly mated with the
ISPSS socket.

The design of the ISPSS socket installation should be such as to prevent
the ingress of fluid into the

power sockets.

The hazard to the aircraft occupants of tripping over the PED lead wire
should be addressed in the design of the ISPSS connector and
installation.

If an automatic overheat protection feature is employed by the ISPSS,
then this feature should not be able to be reset in flight.

The ISPSS should be powered from a non-essential power supply (bus) of
the aircraft.

In addition, appropriate quantitative and/or qualitative failure
analyses of each installed ISPSS should be conducted such that any
likely failure condition would not reduce aircraft safety nor endanger
the occupants. The analysis should consider the effects of the
environment in which any ISPSS equipment is installed, the cooling
arrangements and the safety features employed to prevent a fire or
overheat condition from being inadvertently created.

b\. The ISPSS should be designed so that it may be de-powered at any
time. A clearly labeled and conspicuous means (on/off switch) of
de-powering the ISPSS should be provided as a minimum for the cabin
crew. Cabin configurations may allow for the provision of more than one
switch in the cabin. If multiple switches are used, the design should be
such as to prevent cabin crew confusion when de-powering the ISPSS.

An additional switch may also be provided in the flight deck. This
de-powering feature should allow for the immediate removal of power to
all seat outlets (because circuit breakers are not to be used as
switches, their use for this purpose is not acceptable). The ISPSS
should be deactivated during critical phases of flight such as take-off
and landing.

If flight deck indication of ISPSS status (system "on" or "off") is
deemed necessary, then the indication should be consistent with the
airplane manufacturer's design philosophy with regard to system status
indication.

The overall control of the system should be with the flight and/or cabin
crew. If the control is by a cabin switch only, then airplane flight
manual, operations manual and/or cabin crew operating procedures should
be provided. The ISPSS operating procedures should not conflict nor
cause confusion with any aspect of the normal and non-normal/emergency
airplane operating procedures, such as isolation of fire and smoke from
unknown origins.

Operational procedures should be in place in the operations manual which
should include, as a minimum but not restricted to, the following:

1\) Description of the system; 3

2\) Activation and deactivation of the ISPSS, system control switches
and passenger controls;

3\) Restrictions on use for each phase of flight;

4\) Use of compatible adapters and use of compatible equipment;

5\) Monitoring passenger use of system by Cabin Crew;

6\) Flight deck and cabin crew communication;

7\) Hazards, e.g., trip hazards, overheating of passenger devices
because of being covered by pillows, blankets, etc.;

8\) Information to passengers, such as, safety precautions and warning
that in-seat power may be disconnected at any time if necessary without
notice;

9\) Malfunction of system and individual units and corrective action.
Consideration should be given to automatic deactivation of the ISPSS in
the event of a rapid decompression of the aircraft cabin.

c\. Occupants should be protected against the hazards of electrical
shock. Applicants should submit substantiation of non-hazard to
passengers for all proposed voltages. Substantiation should include
system requirements which eliminate the risk of shock.

d\. Instructions for continued Airworthiness (ICAW) should be prepared
in accordance with the requirements of 14 CFR Section 25.1529. The ICAW
should include all necessary maintenance actions required to maintain
the ISPSS system so that the continued airworthiness of the airplane is
maintained. The ICAW should include maintenance actions necessary to
ensure the continuing effectiveness of ISPSS system features that
prevent electrical shock hazards to passengers (reference paragraph c)
and the features that prevent any radiated or conducted electromagnetic
interference (EMI) to critical or essential aircraft systems (ref.
paragraph g).

e\. To provide for a power connection from the aircraft ISPSS to a PED,
a special adapter should be required for all connected PED\'s to
operate. The special adapter will have the following characteristic: it
should have a mating connector that will plug into an ISPSS outlet on
the aircraft side that cannot be mistaken for, and is not compatible
with, a conventional alternating current (AC) outlet. The intent of this
paragraph is, in part, to control the PED's that are connected to the
power supply by the selection of a particular connector type if the
control of the PED's cannot be effected otherwise (e.g., by equipment
features or cabin crew procedures). Automotive sockets (cigarette
lighter style) would not be acceptable.

f\. ISPSS Power Limitations - Applicants for installation approval
should submit substantiation of proposed maximum power as being
non-hazardous to passengers. Regardless of the level of substantiation,
the maximum power available at each seat outlet should be limited to 100
watts.

An aircraft electrical load analysis should also be conducted that
substantiates the maximum loading that may be utilized from the ISPSS
(ref. 14 CFR Section 25.1351(a) (1)).

g\. Each ISPSS should be designed to prevent any radiated or conducted
EMI to critical or essential aircraft systems. If filters are used to
accomplish this, then the effect of static discharge should also be
addressed.

The applicant for installation approval should also ensure isolation of
all aircraft electrical system buses and electrical systems from any
unacceptable conducted EMI produced by connected PED's (ref. 14 CFR,
Sections 25.1353, 25.1431).

h\. An electromagnetic compatibility (EMC) evaluation of the ISPSS
should be accomplished for all foreseeable EMC worst case conditions.

It is recommended that simulated complex loads be used to check the
conducted and radiated EMI from the ISPSS itself, under the worst load
conditions.

In the absence of a more rational analysis, the following cases should
be considered:

\- One load: minimum, maximum power;

\- Several loads connected;

\- All loads connected: minimum, maximum power.

This should be followed by tests with the intended PED's connected to
check the conducted interference from the PED's (30-100 MHz). Known
worst case loads at worst case locations should be tested. Additional
testing, using computer modeling techniques can also be used.

i\. System testing should be accomplished in accordance with appropriate
chapters of RTCA DO-160D/EUROCAE ED-14D/ISO7137, and should include, as
a minimum, sections 4 through 9, 11, and 15 through 22. Testing for
conducted emissions should include 150 kHz to at least 30 MHz as
depicted in section 21 of document DO-160D. Additionally, the conducted
emissions portion of the testing should be continued up to 100 MHz
(levels as specified in section 21 of DO-160D) to ensure no radio
frequency (RF) coupling paths exist that may channel signals upstream of
the ISPSS.

j\. To guard against damage to ISPSS cable assemblies installed in the
seat itself, seat mounted wiring should have appropriate protection
means, such as protective conduits.

ISPSS wiring and wire bundles should be appropriately routed and secured
and should be physically separated from other aircraft wiring and wire
bundles.

k\. Indication should be provided to enable the cabin crew to detect
which outlets are

in use.

**ADDITIONAL CRITERIA FOR THE INSTALLATION OF 110V,**

**60 HZ AC SYSTEMS**

The following criteria in this appendix should be considered in addition
to the material presented in the main body of this policy for approval
of 110 volt 60 Hz AC ISPSS:

l\. The power outlets should be labeled with the output voltage and
frequency (110V AC, 60 Hz) and suitable safety instructions should be
provided for the passenger detailing the PED's permitted to be used.
These instructions should also include the use of the system, its
limitations, hazards, and the control of airline supplied equipment.

m\. Suitable means of protection, such as differential protection and/or
galvanic isolation (isolation transformer), should be provided to
minimize the risk of passenger shock. This is to guard against
inadvertent contact with live parts of the system.

If differential protection is utilized, it should have the following
characteristics:

Maximum fault current should be limited to 30 mA. Activation time in the
event of a differential fault should be less than or equal to 30 mSec.
In the event of differential protection circuit failure, output power
should be automatically shut down at the outlet.

The fault protection system should include features for monitoring the
health of the fault detection circuits. If a fault is detected, the
power to the outlet should be automatically removed. Any automatic reset
feature should not be permitted.

n\. The ISPSS should be automatically deactivated in the event of a
rapid decompression of the aircraft

**NOTES**

[Note 1]{.underline}: It is not expected that the PED's perform to the
category \'H\' level of radiated emissions (ref. DO-160D Section 21).
However, the power supply system should filter undesirable conducted
emissions generated by the PED\'s or by the ISPSS itself and prevent the
propagation of any unwanted RF into other aircraft systems. (see
paragraph g. above).

[Note 2]{.underline}: The burden of establishing the suitability of use
of PED's on a particular aircraft model will remain with the aircraft
operator as provided for by 14 CFR Section 91.21, *Portable electronic
devices*.

[Note 3]{.underline}: The use of PED's should be prohibited during
critical flight phases such as take-off and landing, as described for
the ISPSS under paragraph b above.

[Note 4]{.underline}: If the ISPSS system includes seat-mounted
equipment, the applicant is accountable for the certification of the
entire ISPSS system, including the seat mounted equipment. As a
reminder, in general, the seat TSO's (Technical Standard Orders) do not
contain electrical requirements. Therefore, electrical aspects of the
ISPSS components are not addressed under the TSO. In addition, many TSO
holders disclaim the basic production and certification of the ISPSS
parts. Therefore, it should not be assumed that electrical components
have been addressed, in any way, under the TSO. Further information
regarding seat mounted ISPSS equipment can be found in the AIR-100
policy memorandum Policy and Guidance on the Approval of Electrical
Components on Aircraft Seating Systems, dated October 27, 1998, or later
revisions.

[Note 5]{.underline}: Operators should provide suitable safety
instructions for the passengers detailing the PED's permitted to be
used. These instructions should also include the use of the system, its
limitations, hazards and the operation of airline supplied equipment.

The general policy stated in this document is not intended to establish
a binding norm; it does not constitute a new regulation and the FAA
would not apply or rely upon it as a regulation. Although the FAA
retains the discretion not to follow the policy in this document, an
Aircraft Certification Office proposing a deviation from this policy
should only do so with the concurrence of the Transport

Standards Staff, ANM-113. Applicants should expect that the
certificating officials will consider this information when making
finding of compliance relevant to new certificate actions. Also, as with
all advisory material, this statement of policy identifies one means,
but not the only means, of compliance.

DISTRIBUTION:

Director, Aircraft Certification Services, AIR-1

Director, Flight Standards Service, AFS-1

Managers, All Directorates

Managers, All Aircraft Certification Offices

Managers, All Manufacturing Inspection Offices

Managers, All Flight Standards District Offices

Managers, All Aircraft Evaluation Groups

Manager, Aircraft Engineering Division, AIR-100

Manager, Transport Standards Staff, ANM-100

Manager, Standardization Branch, ANM-113

Manager, International Branch, ANM-116