[Federal Register Volume 59, Number 201 (Wednesday, October 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-25897]


[[Page Unknown]]

[Federal Register: October 19, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 25

[Docket No. NM-99; Special Conditions No. 25-ANM-89]

 

Special Conditions: Fokker Model F28 Mark 0070 Airplanes, High 
Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for Fokker Model F28 Mark 
0070 airplanes manufactured by Fokker Aircraft B.V. of Schiphol the 
Netherlands. These airplanes are equipped with electrical and 
electronic systems (such as the digital electronic flight instrument 
system (EFIS)), which perform critical functions. 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 (HIRF). These special conditions provide the additional 
safety standards that the Administrator considers necessary to ensure 
that the critical functions performed by these systems are maintained 
when the airplane is exposed to HIRF.

DATES: The effective date of these special conditions is October 6, 
1994; Comments must be received on or before December 5, 1994.

ADDRESSES: Comments on these final special conditions; request for 
comments, may be mailed in triplicate to: Federal Aviation 
Administration, Transport Airplane Directorate (ANM-100), Docket No. 
NM-99, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; or 
delivered in triplicate to the Transport Standards Staff at the above 
address. Comments must be marked ``Docket No. NM-99.'' Comments may be 
inspected in the Rules Docket weekdays, except Federal holidays, 
between 7:30 a.m. and 4:00 p.m.

FOR FURTHER INFORMATION CONTACT:
Tim Dulin, FAA, Standardization Branch, ANM-113, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., 
Renton, Washington 98055-4056; telephone (206) 227-2141.

SUPPLEMENTARY INFORMATION: 

Comments 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 conditions number and be submitted in triplicate 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-99.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On September 17, 1993, Fokker Aircraft B.V. of Schiphol the 
Netherlands, applied for an amendment to Type Certificate A20EU to 
incorporate the Model F28 Mark 0070. This airplane is a derivative of 
the Fokker Model F28 Mark 0100, approved April 21, 1989. The changes 
include: removal of two plug sections forward and aft of the wing to 
decrease overall length by 182 inches; two cargo doors in lieu of 
three; modifications of the aft cargo door due to space constraints 
associated with the shorter fuselage; one pair of Type III overwing 
exists in lieu of two pair, and a new nose wheel tire chine. Both the 
Model F28 Mark 0070 and new production of the Model F28 Mark 0100 will 
incorporate a hydraulic stick pusher in lieu of a pneumatic stick 
pusher, new stabilizer control unit, and a new interior. The Model F28 
Mark 0070 will have a maximum seating capacity of 79 passengers.

Amended Type Certification Basis

    Under the provisions of Sec. 21.101 of the Federal Aviation 
Regulations (FAR), Fokker must show that the Model F28 Mark 0070 meets 
the applicable provisions of the regulations incorporated by reference 
in Type Certificate No. A20EU, or the applicable regulations in effect 
on the date of application for the Model F28 Mark 0070. The regulations 
incorporated by reference in the type certificate are commonly referred 
to as the ``original type certification basis.''
    The regulations incorporated by reference in Type Certificate No. 
A20EU for the Model F28 Mark 0070 are part 25 of the FAR, as amended by 
Amendment 25-1 through 25-60 with certain exceptions which are not 
relevant to these special conditions. In addition, Fokker has elected 
to show compliance with certain later requirements which are also not 
relevant to these special conditions. These special conditions will 
form an additional part of the certification basis.
    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 Fokker Model F28 Mark 0070 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 
at a later date 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).

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 needed for the Model F28 Mark 0070 that would require 
that the electrical and electronic systems which perform critical 
functions such as the EFIS be designed and installed to preclude 
component damage and interruption of function due to the effects of 
HIRF.

High-Intensity Radiated Fields (HIRF)

    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, such as the EFIS, 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 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 18GHz.
    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-2 MHz........................................       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-1 GHz........................................    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
------------------------------------------------------------------------

    The envelope given in paragraph 2 above is a revision to the 
envelope used in previously issued special conditions in other 
certification projects. It is based on new data and SAE AE4R 
subcommittee recommendations. This revised envelope includes data from 
Western Europe and the U.S.
    As discussed above, these special conditions are applicable to 
Fokker Model F28 Mark 0070 airplanes manufactured by Fokker Aircraft 
B.V. of the Netherlands. Should Fokker 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 unusual or novel design features 
on the Fokker Model F28 Mark 0070 airplanes. It is not a rule of 
general applicability and affects only the manufacturer who applied to 
the FAA for approval of these features on the airplane.
    The substance of the special conditions for these airplanes has 
been subjected 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 special conditions is as follows:

    Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355, 
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et 
seq.; E.O. 11514; and 49 U.S.C. 106(g).

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 Fokker Model F28 Mark 0070 
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 field external to the airplane.
    2. The following definition applies with respect to this special 
condition: Critical Function. 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 October 6, 1994.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-25897 Filed 10-18-94; 8:45 am]
BILLING CODE 4910-13-M