[Federal Register Volume 72, Number 1 (Wednesday, January 3, 2007)]
[Rules and Regulations]
[Pages 1-2]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-22436]



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 Rules and Regulations
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  Federal Register / Vol. 72, No. 1 / Wednesday, January 3, 2007 / 
Rules and Regulations  

[[Page 1]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM361; Special Conditions No. 25-341-SC]


Special Conditions: Boeing Model 757-200 Series Airplanes; High-
Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

-----------------------------------------------------------------------

SUMMARY: The FAA issues these special conditions for Boeing Model 757-
200 series airplanes modified by ABX Air, Inc. These modified airplanes 
will have novel or unusual design features when compared with the state 
of technology envisioned in the airworthiness standards for transport 
category airplanes. The modification consists of installing an 
Innovative Solutions and Support Flat Panel Display System that 
performs critical functions. The applicable airworthiness regulations 
do not contain adequate or appropriate safety standards for protecting 
these systems from effects of high-intensity radiated fields (HIRF). 
These special conditions contain the additional safety standards that 
the Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

DATES: The effective date of these special conditions is December 20, 
2006. We must receive your comments on or before February 2, 2007.

ADDRESSES: You may mail or deliver comments on these special conditions 
in duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-113), Docket No. NM361, 1601 
Lind Avenue SW., Renton, Washington 98057-3356. You must mark your 
comments Docket No. NM361.

FOR FURTHER INFORMATION CONTACT: Greg Dunn, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 227-2799; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment for these special conditions is impracticable because these 
procedures would significantly delay certification and delivery of the 
affected aircraft. In addition, the substance of these special 
conditions has been subject to the public comment process in several 
prior instances with no substantive comments received. We therefore 
find that good cause exists for making these special conditions 
effective upon issuance. However, we invite interested persons to take 
part in this rulemaking by submitting written comments. The most 
helpful comments reference a specific portion of the special 
conditions, explain the reason for any recommended change, and include 
supporting data. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
about these special conditions. You may inspect the docket before and 
after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this preamble 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions based on the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, include with your comments a pre-addressed, 
stamped postcard on which the docket number appears. We will stamp the 
date on the postcard and mail it back to you.

Background

    On August 9, 2006, ABX Air, Inc., 145 Hunter Drive, Wilmington, OH 
45177, applied for a supplemental type certificate (STC) to modify 
Boeing Model 757-200 series airplanes. The Boeing Model 757-200 series 
airplanes are large transport category airplanes powered by either 2 
Pratt & Whitney or 2 Rolls-Royce engines. They carry a maximum of 239 
passengers. The modification consists of installing the Innovative 
Solutions and Support (IS&S) Integrated Flat Panel Display System 
(IFPDS). The avionics/electronics and electrical systems installed in 
this airplane have a potential to be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplane.

Type Certification Basis

    Under provisions of 14 CFR 21.101, ABX Air, Inc. must show that the 
Boeing Model 757-200 series airplanes, as changed, continue to meet 
applicable provisions of the regulations incorporated by reference in 
Type Certificate No. A2NM, or the applicable regulations in effect on 
the date of application for the change. The regulations incorporated by 
reference in the type certificate are commonly referred to as the 
``original type certification basis.'' The certification basis for 
Boeing Model 757-200 series airplanes includes applicable sections of 
14 CFR part 25 as amended by Amendments 25-1 through 25-45 effective 
December 1, 1978. In addition, the certification basis includes certain 
special conditions, exemptions, equivalent levels of safety, or later 
amended sections of the applicable part 25 that are not relevant to 
these special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations (part 25, as amended) do not contain adequate or 
appropriate safety standards for the Boeing Model 757-200 series 
airplanes because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 757-200 series airplanes must comply with 
the fuel vent and exhaust emission requirements of 14 CFR part 34 and 
the

[[Page 2]]

noise certification requirements of 14 CFR part 36.
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38, and they become part of the type certification basis under 
the provisions of Sec.  21.101.

Novel or Unusual Design Features

    As noted earlier, the Boeing Model 757-200 series airplanes 
modified by ABX Air, Inc. will incorporate an integrated flat panel 
display system manufactured by IS&S that will perform critical 
functions. This system may be vulnerable to high-intensity radiated 
fields external to the airplane. Current airworthiness standards of 
part 25 do not contain adequate or appropriate safety standards for 
protecting this equipment from adverse effects of HIRF. So this system 
is considered to be a novel or unusual design feature.

Discussion

    As previously stated, there is no specific regulation that 
addresses protection for electrical and electronic systems from HIRF. 
Increased power levels from radio frequency transmitters and the 
growing use of sensitive avionics/electronics and electrical systems to 
command and control airplanes have made it necessary to provide 
adequate protection.
    To ensure that a level of safety is achieved equivalent to that 
intended by the regulations incorporated by reference, special 
conditions are needed for the Boeing Model 757-200 series airplanes 
modified by ABX Air, Inc. These special conditions require that new 
avionics/electronics and electrical systems that perform critical 
functions be designed and installed to preclude component damage and 
interruption of function because of HIRF.

High-Intensity Radiated Fields (HIRF)

    High-power radio frequency transmitters for radio, radar, 
television, and satellite communications can adversely affect operation 
of airplane electric and electronic systems. Therefore, the immunity of 
critical avionics/electronics and electrical systems to HIRF must be 
established.
    Based on surveys and an analysis of existing HIRF emitters, an 
adequate level of protection exists if airplane system immunity is 
demonstrated when exposed to the HIRF environments in either paragraph 
1 or 2 below:
    1. A minimum environment of 100 volts rms (root-mean-square) per 
meter electric field strength from 10 KHz to 18 GHz.
    a. System elements and their associated wiring harnesses must be 
exposed to the environment without benefit of airframe shielding.
    b. Demonstration of this level of protection is established through 
system tests and analysis.
    2. An environment external to the airframe of the field strengths 
shown in the table below for the frequency ranges indicated. Immunity 
to both peak and average field strength components from the table must 
be demonstrated.

------------------------------------------------------------------------
                                                         Field strength
                                                       (volts per meter)
                      Frequency                       ------------------
                                                         Peak    Average
------------------------------------------------------------------------
10 kHz-100 kHz.......................................       50        50
100 kHz-500 kHz......................................       50        50
500 kHz-2 MHz........................................       50        50
2 MHz-30 MHz.........................................      100       100
30 MHz-70 MHz........................................       50        50
70 MHz-100 MHz.......................................       50        50
100 MHz-200 MHz......................................      100       100
200 MHz-400 MHz......................................      100       100
400 MHz-700 MHz......................................      700        50
700 MHz-1 GHz........................................      700       100
1 GHz-2 GHz..........................................     2000       200
2 GHz-4 GHz..........................................     3000       200
4 GHz-6 GHz..........................................     3000       200
6 GHz-8 GHz..........................................     1000       200
8 GHz-12 GHz.........................................     3000       300
12 GHz-18 GHz........................................     2000       200
18 GHz-40 GHz........................................      600       200
------------------------------------------------------------------------
The field strengths are expressed in terms of peak of the root-mean-
  square (rms) over the complete modulation period.

    The environment levels identified above are the result of an FAA 
review of existing studies on the subject of HIRF and of the work of 
the Electromagnetic Effects Harmonization Working Group of the Aviation 
Rulemaking Advisory Committee.

Applicability

    These special conditions are applicable to Boeing Model 757-200 
series airplanes modified by ABX Air, Inc. Should ABX Air, Inc. apply 
at a later date for a supplemental type certificate to modify any other 
model included on Type Certificate No. A2NM to incorporate the same or 
similar novel or unusual design feature, these special conditions would 
apply to that model as well under provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on Boeing Model 757-200 series airplanes modified by ABX Air, Inc. It 
is not a rule of general applicability and affects only the applicant 
who applied to the FAA for approval of these features on the airplane.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.
    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

    Therefore, under the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the supplemental type certification basis for the Boeing Model 757-200 
series airplanes modified by ABX Air, Inc.
    1. Protection from Unwanted Effects of High-Intensity Radiated 
Fields (HIRF). Each electrical and electronic system that performs 
critical functions must be designed and installed to ensure that the 
operation and operational capability of these systems to perform 
critical functions are not adversely affected when the airplane is 
exposed to high-intensity radiated fields.
    2. For the purpose of these special conditions, the following 
definition applies:
    Critical Functions: Functions whose failure would contribute to or 
cause a failure condition that would prevent continued safe flight and 
landing of the airplane.

    Issued in Renton, Washington, on December 20, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-22436 Filed 12-29-06; 8:45 am]
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