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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

CFR Citation: 14 CFR Part 25

Docket ID: [Docket No. NM192, Special Conditions No. 25-181-SC]

NOTICE: RULES

ACTION: Airworthiness standards:

DOCUMENT ACTION: Final special conditions; request for comments.

SUBJECT CATEGORY: Special Conditions: Raytheon Model Hawker 800XP Airplane; High- Intensity Radiated Fields

DATES: The effective date of these special conditions is July 6, 2001. Comments must be received on or before August 17, 2001.

DOCUMENT SUMMARY: These special conditions are issued for Raytheon Aircraft Company Model Hawker 800XP airplanes modified to incorporate the Collins Proline 21 avionics system. These modified airplanes will have novel and unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. The modification incorporates the installation of a four tube active matrix liquid crystal display Electronic Flight Information System (EFIS) with an Engine Indicating System (EIS), autopilot with integral mach trim capability, new air data computers, and new Attitude and Heading Reference System (AHRS) with solid state sensors. The applicable airworthiness standards do not contain adequate or appropriate safety standards for the protection of these systems from the effects of highintensity 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 provided by the existing airworthiness standards.

SUMMARY: Special conditions—; Raytheon Model Hawker 800XP airplanes,

SUPPLEMENTAL INFORMATION

The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay issuance of the approval design and thus delivery of the affected aircraft. In addition, the substance of these special conditions has been subject to the public comment process in several prior instances with no substantive comments received. 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 regulatory docket or special conditions 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 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. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to these special conditions must include a selfaddressed, stamped postcard on which the following statement is made: ``Comments to Docket No. NM192.'' The postcard will be date stamped and returned to the commenter.

Background

On August 4, 1998, Raytheon Aircraft Company, PO Box 85, Wichita, Kansas 672010085, applied for a supplemental type certificate to modify Raytheon Aircraft Company Model Hawker 800XP airplanes listed on Type Certificate No. A21EA. The Model Hawker 800XP is a twin engine transport airplane. It has an executive interior and is capable of carrying two flight crewmembers and up to fifteen passengers. This model is powered by two aft mounted Allied Signal TFE 7315BR engines. The modification incorporates the installation of the Rockwell Collins Proline 21 avionics system which includes a four tube active matrix liquid crystal display Electronic Flight Information System (EFIS) with an Engine Indicating System (EIS) that display critical flight parameters to the flightcrew. These systems can be susceptible to disruption to command and/or response signals as a result of electrical and magnetic interference. This disruption of signals could result in loss of all critical flight displays and annunciations or present misleading information to the pilot.

Type Certification Basis

Under the provisions of 14 CFR 21.101, Raytheon must show that the Raytheon Model Hawker 800XP airplanes, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. A3EU, 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 incorporated by reference in Type Certificate No. A21EA are as follows: the certification basis for the modified Raytheon Model Hawker 800XP airplane includes the British Civil Airworthiness Requirements (CAR) 10, and specific additional requirements of 14 CFR part 25, as listed in the Type Certificate Data Sheet (TCDS) No. A3EU.

If the Administrator finds that the applicable airworthiness regulations
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(i.e., part 25) do not contain adequate or appropriate safety standards for the Raytheon Model Hawker 800XP airplane 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 Raytheon Model Hawker 800XP airplane must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the noise certification requirements 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 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 Raytheon apply for approval for a supplemental type certificate 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).

Novel or Unusual Design Features

The Raytheon Model Hawker 800XP airplane will incorporate the following novel or unusual design features: the Rockwell Collins Proline 21 avionics system which includes a four tube active matrix liquid crystal display Electronic Flight Information System (EFIS) with an Engine Indicating System (EIS) that display critical flight parameters to the flightcrew. These systems can be susceptible to disruption to command and/or response signals as a result of electrical and magnetic interference. This disruption of signals could result in loss of all critical flight displays and annunciations or present misleading information to the pilot.

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 avionic/electronic and electrical 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 Raytheon Model Hawker 800XP as modified by Raytheon. These special conditions require that new avionic/ electronic and electrical systems, such as the AHRS and 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.

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 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 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 with either paragraph 1, or paragraph 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.

1. 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 meter) Frequency
Peak Average 10 kHz100kHz................................. 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 The field strengths are expressed in terms of peak of the rootmean square (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 Raytheon Model Hawker 800XP airplane modified
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by the Raytheon Aircraft Company. Should Raytheon apply at a later date for approval of a design change to modify any other model included on the same type certificate 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).

Conclusion

This action affects only certain novel or unusual design features on Raytheon Model Hawker 800XP airplane modified by the Raytheon Aircraft Company. 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 subjected to the notice and comment period 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 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 type certification basis for Raytheon Model Hawker 800XP airplanes modified by:

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 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 July 6, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 0117961 Filed 71701; 8:45 am] BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Mark Quam, FAA, Standardization Branch, ANM113, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 980554056; telephone (425) 2272145; facsimile (425) 2271149.