[Federal Register Volume 69, Number 183 (Wednesday, September 22, 2004)]
[Rules and Regulations]
[Pages 56674-56676]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-21225]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM288; Special Conditions No. 25-271-SC]


Special Conditions: Lockheed Martin Corporation Model 1329-23A, -
23D, -23E, and 1329-25 Airplanes; High-Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for Lockheed Martin 
Corporation Model 1329-23A, -23D, -23E and 1329-25 airplanes modified 
by Garrett Aviation Services. These modified airplanes will have novel 
or unusual design features when compared to the state of technology 
envisioned in the airworthiness standards for transport category 
airplanes. The modification incorporates the installation of four 
Honeywell N1 Digital Electronic Engine Controls (DEEC) that perform 
critical functions. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for the protection of 
these systems from the 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 September 13, 
2004. Comments must be received on or before October 22, 2004.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM288, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; or delivered in duplicate 
to the Transport Directorate at the above address. All comments must be 
marked Docket No. NM288.

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 98055-4056; telephone (425) 227-2799; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment is impracticable because these procedures would significantly 
delay certification of the airplane and thus 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. The FAA therefore finds that 
good cause exists for making these special conditions effective upon 
issuance; however, the FAA invites interested persons to participate in 
this rulemaking by submitting written comments, data, or views. 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 
concerning these special conditions. The docket is available for public 
inspection 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

[[Page 56675]]

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 December 4, 2003, Garrett Aviation Services, 1200 North Airport 
Drive, Capital Airport Springfield, IL 62707, applied for a 
supplemental type certificate (STC) to modify Lockheed Martin 
Corporation Model 1329-23A, -23D, -23E and 1329-25 airplanes. These 
models are currently approved under Type Certificate No. 2A15. They are 
transport category airplanes. The Lockheed Martin Corporation Model 
1329-23A, -23D, -23E and 1329-25 airplanes are powered by four 
AiResearch TFE731-3-1F turbofan engines and have a maximum takeoff 
weight of 44,500 pounds. This airplane operates with a 2-pilot crew and 
can hold up to 10 passengers. The modification incorporates the 
installation of Honeywell N1 Digital Electronic Engine Controls (DEEC). 
The N1 Digital Electronic Engine Controls (DEEC) are a replacement for 
the existing analog electronic engine control (EEC) and also provide 
additional functional capability to the system. The digital avionics/
electronics and electrical systems installed under this project in 
these airplanes have the potential to be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplane.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Garrett Aviation Services 
must show that the Lockheed Martin Corporation Model 1329-23A, -23D, -
23E and 1329-25 airplanes, as changed, continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. 2A15, 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 the 
Lockheed Martin Corporation Model 1329-23A, -23D, -23E and 1329-25 
airplanes includes 14 CFR Part 25, dated February 1, 1964, as amended 
by Amendments 25-1 through 25-20, except for special conditions and 
exceptions noted in Type Certificate Data Sheet (TDCS) 2A15.
    If the Administrator finds that the applicable airworthiness 
regulations (that is, 14 CFR part 25, as amended) do not contain 
adequate or appropriate safety standards for the Lockheed Martin 
Corporation Model 1329-23A, -23D, -23E and 1329-25 airplanes because of 
novel or unusual design features, special conditions are prescribed 
under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Lockheed Martin Corporation Model 1329-23A, -23D, -23E 
and 1329-25 airplanes must comply with the fuel vent and exhaust 
emission requirements of 14 CFR part 34 and the noise certification 
requirements of 14 CFR part 36.
    Special conditions, as defined in 14 CFR 11.19, are issued in 
accordance with Sec.  11.38 and become part of the type certification 
basis in accordance with Sec.  21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should Garrett Aviation Services apply at a later date 
for a supplemental type certificate to modify any other model included 
on Type Certificate No. 2A15 to incorporate the same or similar novel 
or unusual design features, these special conditions would also apply 
to the other model under the provisions of 14 CFR 21.101.

Novel or Unusual Design Features

    The Lockheed Martin Corporation Model 1329-23A, -23D, -23E and 
1329-25 airplanes modified by Garrett Aviation Services will 
incorporate Honeywell N1 Digital Electronic Engine Controls (DEEC) that 
will perform critical functions. These systems have the potential to be 
vulnerable to high-intensity radiated fields (HIRF) external to the 
airplane. The current airworthiness standards of part 25 do not contain 
adequate or appropriate safety standards for the protection of this 
equipment from the adverse effects of HIRF. Accordingly, these systems 
are considered to be novel or unusual design features.

Discussion

    There is no specific regulation that addresses protection 
requirements for electrical and electronic systems from HIRF. Increased 
power levels from ground-based radio 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 Lockheed Martin Corporation Model 1329-
23A, -23D, -23E and 1329-25 airplanes modified by Garrett Aviation 
Services. 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 due to both the direct and indirect effects of HIRF.

High-Intensity Radiated Fields (HIRF)

    With the trend toward increased power levels from ground-based 
transmitters and the advent of space and satellite communications, 
coupled with electronic command and control of the airplane, the 
immunity of critical avionics/electronics and electrical systems to 
HIRF must be established.
    It is not possible to precisely define the HIRF to which the 
airplane will be exposed in service. There is also uncertainty 
concerning the effectiveness of airframe shielding for HIRF. 
Furthermore, coupling of electromagnetic energy to cockpit-installed 
equipment through the cockpit window apertures is undefined. Based on 
surveys and analysis of existing HIRF emitters, an adequate level of 
protection exists when compliance with the HIRF protection special 
condition is shown with either paragraph 1, or 2 below:
    1. A minimum threat of 100 volts rms (root-mean-square) per meter 
electric field strength from 10 KHz to 18 GHz.
    a. The threat must be applied to the system elements and their 
associated wiring harnesses without the benefit of airframe shielding.
    b. Demonstration of this level of protection is established through 
system tests and analysis.
    2. A threat external to the airframe of the field strengths 
identified in the table below for the frequency ranges indicated. Both 
peak and average field strength components from the table are to be 
demonstrated.

------------------------------------------------------------------------
                                                  Field strength (volts
                                                       per meter)
                   Frequency                   -------------------------
                                                    Peak       Average
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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

[[Page 56676]]

 
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
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 The field strengths are expressed in terms of peak of the root-mean-
  square (rms) over the complete modulation period.

    The threat levels identified above are the result of an FAA review 
of existing studies on the subject of HIRF, in light of the ongoing 
work of the Electromagnetic Effects Harmonization Working Group of the 
Aviation Rulemaking Advisory Committee.

Applicability

    As discussed above, these special conditions are applicable to 
Lockheed Martin Corporation Model 1329-23A, -23D, -23E and 1329-25 
airplanes modified by Garret Aviation Services. Should Garrett Aviation 
Services apply at a later date for a supplemental type certificate to 
modify any other model included on Type Certificate No. 2A15 to 
incorporate the same or similar novel or unusual design features, these 
special conditions would apply to that model as well under the 
provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on the Lockheed Martin Corporation Model 1329-23A, -23D, -23E and 1329-
25 airplanes modified by Garrett Aviation Services. 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.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances and has been 
derived without substantive change from those previously issued. 
Because a delay would significantly affect the certification of the 
airplane, which is imminent, the FAA has determined that prior public 
notice and comment are unnecessary and impracticable, and good cause 
exists for adopting these special conditions upon issuance. The FAA is 
requesting comments to allow interested persons to submit views that 
may not have been submitted in response to the prior opportunities for 
comment described above.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and record keeping 
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

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the supplemental type certification basis for the Lockheed Martin 
Corporation Model 1329-23A, -23D, -23E and 1329-25 airplanes modified 
by Garrett Aviation Services.
    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 the continued safe flight 
and landing of the airplane.

    Issued in Renton, Washington, on September 13, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-21225 Filed 9-21-04; 8:45 am]
BILLING CODE 4910-13-P