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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

CFR Citation: 14 CFR Part 25

Docket ID: [Docket No. NM202; Special Conditions No. 25-191-SC]

NOTICE: RULES

ACTION: Airworthiness standards:

DOCUMENT ACTION: Final special conditions; request for comments.

SUBJECT CATEGORY: Special Conditions: Gulfstream G-1159, G-1159A, G-1159B Series Airplanes; High-Intensity Radiated Fields (HIRF)

DATES: The effective date of these special conditions is November 6, 2001.

Comments must be received on or before December 17, 2001.

DOCUMENT SUMMARY: These special conditions are issued for Gulfstream G-1159, G- 1159A, G1159B series airplanes modified by Garrett Aviation Services. These modified airplanes will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. The modification incorporates the installation of a Honeywell Epic Control Display System for Retrofit (CDSR). The system consists of dual Electronic Primary Flight Display Systems, which replace the existing Primary Flight Display System. The Electronic Primary Flight Display Systems will utilize electrical and electronic systems 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 highintensityradiated 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.

SUMMARY: Gulfstream G-1159, G-1159A, G-1159B series airplanes,

SUPPLEMENTAL INFORMATION

The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay certification of the airplane and thus delivery of the affected aircraft. The FAA therefore finds that good cause exists for making these special conditions effective upon issuance.

Comments Invited

Interested persons are invited to submit such written data, views, or arguments as they may desire. Communications should identify the rules docket number and be submitted in duplicate to the address specified above. The Administrator will consider all communications received on or before the closing date for comments. The special conditions may be changed in light of the comments received. All comments received 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 these special conditions must include with those comments a selfaddressed, stamped postcard on which the following statement is made: ``Comments to Docket No. NM202.'' The postcard will be date stamped and returned to the commenter. Background

On January 9, 2001, Garrett Aviation Services, 1200 North Airport Drive, Capital Airport, Springfield, Illinois 62707, applied for a Supplemental Type Certificate (STC) for the Gulfstream G1159, G1159A, G1159B series airplanes. The Gulfstream G1159, G1159A, G1159B series airplanes are small transport category airplanes powered by two turbofan engines with a maximum takeoff weight of 69,700 pounds. The aircraft operate with a two pilot crew and can carry up to 19 passengers. The modified airplanes incorporate the installation of a Honeywell Epic Control Display System for Retrofit (CDSR). The system consists of dual Electronic Primary Flight Display systems that replace the existing Primary Flight Display systems. The Honeywell Epic DCSR has the potential to be vulnerable to highintensity 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 Gulfstream G1159, G1159A, G1159B series airplanes, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. A12EA, 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 included in the certification basis for the Gulfstream G1159, G1159A, G1159B series airplanes include 14 CFR part 25, as amended by Amendment 251 through Amendment 2541 except for special conditions and exceptions noted in Type Certificate Data Sheet (TCDS) A12EA.

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 G1159, G1159A, G 1159B series airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of Sec. 21.16.

In addition to the applicable airworthiness regulations and special conditions, the Gulfstream G1159, G1159A, G1159B series airplanes must comply with the fuel vent and exhaust emission requirement of 14 CFR part 34 and the noise certification requirement of 14 CFR part 36.

Special conditions, as defined in Sec. 11.19, are issued in accordance with Sec. 11.38 and become part of the airplane's 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 a supplemental type certificate to modify any other model included on the same type certificate to incorporate the same novel or unusual design features, these special conditions would also apply to the other model under the provisions of Sec. 21.101(a)(1).
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Novel or Unusual Design Features

The Gulfstream G1159, G1159A, G1159B series airplanes will incorporate dual Electronic Primary Flight Display Systems that will perform critical functions. The existing airworthiness standards (14 CFR part 25) do not contain adequate or appropriate safety standards that address protecting this equipment from the adverse effects of HIRF. These instruments may be vulnerable to HIRF external to the airplane. Accordingly, these instruments are considered to be a novel or unusual design feature

Discussion

There is no specific regulation that addresses protection requirements for electrical and electronic systems from HIRF. Increased power levels from groundbased radio transmitters and the growing use of sensitive avionics/electronics 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 that is equivalent to that intended by the regulations incorporated by reference, special conditions are needed for the Gulfstream G1159, G1159A, G1159B series airplanes modified to incorporate dual Electronic Primary Flight Display Systems. These special conditions will require that these instruments, which 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.

HighIntensity Radiated Fields (HIRF)

With the trend toward increased power levels from groundbased transmitters, plus 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 cockpitinstalled 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 in accordance with either paragraph 1 or 2 below:

1. A minimum threat of 100 volts rms 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 following field strengths for the frequency ranges indicated. Both peak and average field strength components from the Table are to be demonstrated. Field strength (volts per Frequency meter)
Peak Average 10 kHz100 kHz........................................ 50 50 100 kHz500 kHz....................................... 50 50 500 kHz2 MHz......................................... 50 50 2 MHz30 MHz.......................................... 100 100 30 MHz70 MHz......................................... 50 50 70 MHz100 MHz........................................ 50 50 100 MHz200 MHz....................................... 100 100 200 MHz400 MHz....................................... 100 100 400 MHz700 MHz....................................... 700 50 700 MHz1 GHz......................................... 700 100 1 GHz2 GHz........................................... 2000 200 2 GHz4 GHz........................................... 3000 200 4 GHz6 GHz........................................... 3000 200 6 GHz8 GHz........................................... 1000 200 8 GHz12 GHz.......................................... 3000 300 12 GHz18 GHz......................................... 2000 200 18 GHz40 GHz......................................... 600 200 Note.The field strengths are expressed in terms of peak of the root meansquare (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 the Gulfstream G1159, G1159A, G1159B series airplanes modified by Garrett Aviation Services to incorporate dual Electronic Primary Flight Display Systems. Should Garrett Aviation Services apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. A12EA to incorporate the same novel or unusual design features, 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 novel or unusual design features on the Gulfstream G1159, G1159A, G1159B series 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 airplanes.

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 recordkeeping 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 Gulfstream G1159, G 1159A, G1159B series airplanes modified by Garrett Aviation Services.

1. Protection from Unwanted Effects of HighIntensity 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 highintensity 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.

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Issued in Renton, Washington, on November 6, 2001. Jeff Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 0128676 Filed 111501; 8:45 am] BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Connie Beane, FAA, Standardization Branch, ANM113, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 980554056; telephone (425) 2272976; facsimile (425) 2271320.