[Federal Register Volume 61, Number 158 (Wednesday, August 14, 1996)]
[Rules and Regulations]
[Pages 42144-42146]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-20756]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-130; Special Conditions No. 25-ANM-120]


Special Conditions: Cessna Model 550 (Serial Number 550-0801 and 
on); 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 Cessna Model 550 
airplane, serial number 550-0801 and on. These airplanes utilize new 
avionics/electronic systems, such as an Electronic Flight Instrument 
Systems (EFIS), which perform critical functions. The applicable 
regulations do not contain adequate or appropriate safety standards for 
the protection of this system 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 August 6, 
1996. Comments must be received on or before September 13, 1996.

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-130, 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-130. 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:
Mark Quam, FAA, Standardization Branch, ANM-113, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., 
Renton, Washington, 98055-4056; telephone (206) 227-2145; facsimile 
(206) 227-1149.

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 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-130.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On June 30, 1994, Cessna Aircraft Company, One Cessna Boulevard, 
Wichita, Kansas, applied for a type design change to the Model 550. The 
Model 550 airplanes are pressurized, executive transport type 
airplanes, powered by two fuselage-mounted turbofan engines and 
approved under Type Certificate No A22CE. As changed, these airplanes 
will differ from previously approved Model 550 airplanes, in part, by 
the installation of Pratt & Whitney Canada PW530A engines with thrust 
reversers; trailing link landing gear; an Electronic Flight Instrument 
System (EFIS); digital anti-skid system; structural, electrical, and 
hydraulic modifications to support the engine and landing gear change; 
and a weight increase. The applicant intends to introduce the changes 
in production beginning with serial number 550-0801.

Amended Type Certification Basis

    Under the provisions of Sec. 21.101 of 14 CFR part 21, Cessna 
Aircraft Company must show that the Model 550, as changed, continues to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate A22CE, 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 regulations, 
including those referenced in A22CE, that apply to the Model 550, 
serial number 550-0801 and on, are as follows:
    (1) Part 25 of the Federal Aviation Regulations effective February 
1, 1965, as amended by Amendments 25-1 through 25-17; with the 
following exceptions: Section 25.305, as amended by Amendments 25-1 
through 25-54. Section 25.1401, as amended by Amendments 25-1 through 
25-27. Section 25.1387, as amended by Amendments 25-1 through 25-30. 
Sections 25.1303(a)(2) and 25.1385(c), as amended by Amendments 25-1 
through 25-38.
    Sections 25.125, 25.251, 25.337, 25.493, 25.731, 25.733, 25.735, 
25.867, 25.869, 25.901, 25.903, 25.933, 25.934, 25.939, 25.943, 25.951, 
25.952, 25.1001, 25.1041, 25.1043, 25.1045, 25.1091, 25.1093, 25.1103, 
25.1121, 25.1123, 25.1143, 25.1163, 25.1165, 25.1181, 25.1183, 25.1185, 
25.1189, 25.1195, 25.1197, 25.1203, 25.1205 (revoked), 25.1207, 
25.1305, 25.1316, 25.1322, 25.1326, 25.1337, 25.1351, 25.1438, 25.1521, 
25.1549, and 25.1551, as amended by Amendments 25-1 through 25-82.
    (2) Part 36 of the Federal Aviation Regulations effective December 
1, 1969, plus any amendments in effect at the time of certification.

[[Page 42145]]

    (3) Part 34 of the Federal Aviation Regulations effective September 
10, 1990, plus any amendments in effect at the time of engine 
manufacture.
    (4) For Electronic Flight Instrument Systems only, compliance must 
be demonstrated for the additional regulations: Sections 25.1301, and 
25.1303(b), as amended by Amendments 25-1 through 25-38; 25.1309, 
25.132 (a), (b), (d) and (e), 25.1331, 25.1333, and 25.1335, as amended 
by Amendments 25-1 through 25-41.
    These special conditions form an additional part of the type 
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 Cessna Model 550, serial number 
550-0801 and on, 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 
14 CFR 11.49 after public notice, as required by Secs. 11.28 and 
11.29(b), 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 applicant apply for an amended type 
certificate to include a new model or to modify any other model 
included on the same type certificate to incorporate the same novel or 
unusual design feature, these special conditions would also apply to 
the other model under the provisions of Sec. 21.101(a)(1). Similarly, 
these special conditions would also apply to Model 550 airplanes with 
serial numbers earlier than 550-0801, if those airplanes are modified 
to incorporate the same novel or unusual design feature.

Novel or Unusual Design Features

    The Cessna Model 550, serial number 550-0801 and on, incorporates 
new avionics/electronic systems, such as an electronic flight 
instrument system (EFIS), that perform critical functions. 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, a special 
condition is needed for the Cessna Model 550, serial number 550-0801 
and on, as modified by Cessna Aircraft Company, which requires that new 
electrical and electronic systems, such as the EFIS, 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, 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 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-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-2GHz..........................................     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 are applicable to 
those Cessna Model 550 airplanes that utilize avionics/electronics 
systems which perform critical functions. Should Cessna apply at a 
later date for an amended type certificate to include a new model or to 
modify any other model included on type Certificate No. A22CE to 
incorporate 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). Although the manufacturer intends to introduce these 
changes in production beginning with serial number 550-0801, the 
special conditions would be equally applicable to earlier airplanes if 
those airplanes are modified to incorporate the same novel or unusual 
design features.

Conclusion

    This action affects only certain design features on Cessna Model 
550 airplanes, serial number 550-0801 and on. 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 the special conditions for this airplane has been 
subject 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 this special condition is as follows:

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

[[Page 42146]]

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 Cessna Model 550, when equipped 
with avionics/electronics systems which perform critical functions.
    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 condition, 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 August 6, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 96-20756 Filed 8-13-96; 8:45 am]
BILLING CODE 4910-13-M