[Federal Register Volume 60, Number 167 (Tuesday, August 29, 1995)]
[Rules and Regulations]
[Pages 44748-44749]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-21333]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-109; Special Conditions No. 25-NM-105]


Special Condition: Gulfstream Aerospace Corporation, Model 
Gulfstream V, High-Intensity Radiated Fields

agency: Federal Aviation Administration, DOT.

action: Final special conditions.

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summary: These special conditions are for the Gulfstream Model 
Gulfstream V airplane. This new airplane will utilize new avionics/
electronic systems 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.

effective date: September 28, 1995.

for further information contact: Gerald Lakin, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056, (206) 
227-1187.

SUPPLEMENTARY INFORMATION:

Background

    On February 26, 1992, Gulfstream Aerospace Corporation, P.O. Box 
2206, Savannah, GA 31402-2206, applied for an amended type certificate 
in the transport airplane category for the Model Gulfstream V airplane. 
The Gulfstream V is a T-tail, low swept wing, business jet airplane 
powered by two Rolls-Royce BR710-48 turbofan engines mounted on pylons 
extending from the aft fuselage. Each engine will be capable of 
delivering 14,750 pounds thrust. The flight controls will be powered 
and capable of manual reversion. The airplane has a seating capacity of 
up to nineteen passengers, and a maximum takeoff weight of 89,000 
pounds.

Type Certification Basis

    Under the provisions of Sec. 21.101 of the FAR, Gulfstream must 
show, except as provided in Sec. 25.2, that the Model Gulfstream V 
meets the applicable provisions of part 25, effective February 1, 1965, 
as amended by Amendments 25-1 through 25-81. In addition, the proposed 
certification basis for the Model Gulfstream V includes part 34, 
effective September 10, 1990, plus any amendments in effect at the time 
of certification; and part 36, effective December 1, 1969, as amended 
by Amendment 36-1 through the amendment in effect at the time of 
certification. No exemptions are anticipated. These special conditions 
form an additional part of the type certification basis. In addition, 
the certification basis may include other special conditions that are 
not relevant to these special conditions.

[[Page 44749]]

    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 Gulfstream V 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 Gulfstream V incorporates new avionic/electronic 
installations, including a digital Electronic Flight Instrument System 
(EFIS), Air Data System, Attitude and Heading Reference System (AHRS), 
Navigation and Communication System, Autopilot System, 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 Gulfstream V which require that new 
technology electrical and electronic systems, such as the EFIS, FADEC, 
AHRS, 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 paragraph 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 Gulfstream V. Should Gulfstream 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).

Discussion of Comments

    Notice of Proposed Special Conditions No. SC 95-3-NM for the 
Gulfstream Aerospace Corporation, Model Gulfstream V, was published in 
the Federal Register on June 1, 1995 (60 FR 28550). One comment was 
received. The commenter states that the presently proposed 
certification basis for the Gulfstream V is part 25 of the FAR as 
amended by Amendments 25-1 through 25-81 instead of through 25-75 as 
stated in the notice. The FAA agrees with the commenter and has 
incorporated the change in this document.

Conclusion

    This action affects certain design features only on the Gulfstream 
V airplane. 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.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Federal Aviation Administration, 
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, the following special conditions are issued as part of 
the type certification basis for the Gulfstream Aerospace Corporation 
Model Gulfstream V 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 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 August 18, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 95-21333 Filed 8-28-95; 8:45 am]
BILLING CODE 4910-13-M