[Federal Register Volume 62, Number 69 (Thursday, April 10, 1997)]
[Rules and Regulations]
[Pages 17531-17532]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-9244]



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Rules and Regulations
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Federal Register / Vol. 62, No. 69 / Thursday, April 10, 1997 / Rules 
and Regulations

[[Page 17531]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-140; Special Conditions No. 25-ANM-125]


Special Conditions: Lockheed Martin Aerospace Corp. Model L382J 
Airplane, High-Intensity Radiated Fields

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Lockheed Martin 
Aerospace Corp. Model L382J airplane. This model airplane will utilize 
new avionics/electronic systems, Mil Std 1553 data buses and dual head-
up displays that provide critical data to the flightcrew. The 
applicable regulations do not contain adequate or appropriate safety 
standards for the protection of these systems from the effects of high-
intensity radiated fields. 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 April 2, 1997. 
Comments must be received on or before May 27, 1997.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Office of the Assistant 
Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-140, 1601 Lind 
Avenue SW., Renton, Washington 98055-4056; or delivered in duplicate to 
the Office of the Assistant Chief Counsel at the above address. 
Comments must be marked: Docket No. NM-140. Comments may be inspected 
in the Rules Docket weekdays, except Federal holidays, between 7:30 
a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Mike Zielinski, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(206) 227-2279.

SUPPLEMENTARY INFORMATION:

Comment Invited

    The FAA has determined that good cause exists for making these 
special conditions effective upon issuance; however, interested persons 
are invited to submit such written data, views, or arguments as they 
may desire. Communications should identify the regulatory docket and 
special condition number and be submitted in duplicate to the address 
specified above. All communications received on or before the closing 
date for comments will be considered by the Administrator. These 
special conditions may be changed in light of the comments received. 
All comments submitted will be available in the Rules Docket for 
examination by interested persons, both before and after the closing 
date for comments. A report summarizing each substantive public contact 
with FAA personnel concerning this rulemaking will be filed in the 
docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this request must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM-140.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On August 2, 1992, Lockheed Martin Aerospace Corp. applied for an 
amendment to their Type Certificate No. A1SO to include their new Model 
L382J. The Model L382J is a derivative of the L382B/E/G currently 
approved under Type Certificate No. A1SO, and features a new engine 
(with approximately the same rated horsepower, but heavily flat-rated) 
and propeller, both of which are controlled by a full authority digital 
engine control. Additionally, the flight deck is substantially modified 
by the installation of four liquid crystal flight displays, dual head-
up displays, and Mil Std 1553 data buses. The flight engineer position 
is deleted, requiring automation of some functions as well as redesign 
of the front and overhead panels. Some structure has been modified but 
the aerodynamics of the airplane are essentially unchanged. The latest 
Part 25 requirement will be used for all significantly modified 
portions of the Model 382J (as compared to the present L382), and, for 
the unmodified portions of the airplane, the applicable certification 
standard will be the Part 25 rules that were effective on February 1, 
1965.

Type Certification Basis

    Under the provisions of Sec. 21.101, Lockheed Martin Aerospace 
Corp. must show that the Model L382J airplanes meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A1SO or the applicable regulations in effect on the 
date of application for the changes to the Model L382. In addition, the 
certification basis includes certain special conditions and later 
amended sections of Part 25 that are not relevant to these proposed 
special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., Part 25, as amended) do not contain adequate or 
appropriate safety standards for the L382J because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec. 21.16 to establish a level of safety equivalent to 
that established in the regulations.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28 
and 11.29, and become part of the type certification basis in 
accordance with Sec. 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design feature, the special conditions would also apply to the 
other model under the provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The Model L382J incorporates new avionic/electronic installations, 
including a digital Electronic Flight

[[Page 17532]]

Instrument System (EFIS), Mil Std 1553 data buses and dual head-up 
displays that provide critical data to the flightcrew and a Full 
Authority Digital Engine Control (FADEC) system that controls critical 
engine parameters. These systems may be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplane.

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 electrical and electronic 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 issued for the L382J which require that new technology 
electrical and electronic systems, such as the EFIS, FADEC, HUD, etc., 
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

    With the trend toward increased power levels from ground based 
transmitters, plus the advent of space and satellite communications, 
coupled with electronic command and control of the airplane, the 
immunity of critical digital avionics 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 paragraphs 1 or 2 below:
    1. A minimum threat of 100 volts per meter peak 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 following field 
strengths for the frequency ranges indicated.

------------------------------------------------------------------------
                                                      Peak  (V/  Average
                      Frequency                          M)       (V/M) 
------------------------------------------------------------------------
10 KHz-100 KHz......................................        50        50
100 KHz-500 KHz.....................................        60        60
500 KHz-2000 KHz....................................        70        70
2 MHz-30 MHz........................................       200       200
30 MHz-100 MHz......................................        30        30
100 MHz-200 MHz.....................................       150        33
200 MHz-400 MHz.....................................        70        70
400 MHz-700 MHz.....................................     4,020       935
700 MHz-1000 MHz....................................     1,700       170
1 GHz-2 GHz.........................................     5,000       990
2 GHz-4 GHz.........................................     6,680       840
4 GHz-6 GHz.........................................     6,850       310
6 GHz-8 GHz.........................................     3,600       670
8 GHz-12 GHz........................................     3,500     1,270
12 GHz-18 GHz.......................................     3,500       360
18 GHz-40 GHz.......................................     2,100       750
------------------------------------------------------------------------

    As discussed above, these special conditions would be applicable 
initially to the Model L382J. Should Lockheed Martin Aerospace Corp. 
apply at a later date for a change to the type certificate to include 
another model incorporating the same novel or unusual design feature, 
these special conditions would apply to that model as well, under the 
provisions of Sec. 21.101(a)(1).

Conclusion

    This action affects only certain design features on the Lockheed 
Martin Aerospace Corporation Model L382J airplanes. 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 for this airplane has 
been submitted to the notice and comment procedure in several prior 
instances and has been derived without substantive change from those 
previously issued. It is unlikely that prior public comment would 
result in a significant change from the substance contained herein. For 
this reason, and 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 immediately. Therefore, these special conditions are being 
made effective 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 recordkeeping 
requirements.

    The authority citation for these proposed 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 type certification basis for the Lockheed Martin Aerospace Corp. 
Model L382J airplanes.
    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 this 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 April 2, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 97-9244 Filed 4-9-97; 8:45 am]
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