Source: https://www.federalregister.gov/documents/2007/12/28/E7-25143/special-condition-bell-helicopter-textron-canada-limited-model-429-helicopters-high-intensity
Timestamp: 2017-11-19 07:38:18
Document Index: 34605469

Matched Legal Cases: ['art 27', 'art 29', 'art 27', 'art 29', 'art 27', 'art 36', 'art 36', '§\u2009611', '§\u200911', '§\u200911', '§\u200921', '§\u200921']

Federal Register :: Special Condition: Bell Helicopter Textron Canada Limited Model 429 Helicopters, High Intensity Radiated Fields
The effective date of this special condition is December 11, 2007. Comments must be received on or before February 11, 2008.
73579-73582 (4 pages)
Docket No. SW017
Special Condition No. 27-017-SC
https://www.federalregister.gov/d/E7-25143 https://www.federalregister.gov/d/E7-25143
Send comments on this special condition in duplicate to: Federal Aviation Administration, Rotorcraft Directorate, Attention: Rules Docket (ASW-111) Docket No. SW017, Fort Worth, Texas 76193-0111, or deliver them in duplicate to the Rotorcraft Directorate at 2601 Meacham Blvd., Fort Worth, Texas 76137. Comments must be marked: Docket No. SW017. You may inspect comments in the Docket that is maintained in Room 448 in the Rotorcraft Directorate offices at 2601 Meacham Blvd., Fort Worth, Texas, on weekdays, except Federal holidays, between 8:30 a.m. and 4 p.m.
Carroll Wright, Electrical Flight Systems Start Printed Page 73580Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards, 2601 Meacham Blvd., Fort Worth, Texas 76193-0110; telephone (817) 222-5120, FAX (817) 222-5961.
You are invited to submit written data, views, or arguments. Your communications should include the regulatory docket or special condition number and be sent in duplicate to the address stated above. We will consider all communications received on or before the closing date and may change the special condition in light of the comments received. Interested persons may examine the Docket. We will file a report summarizing each substantive public contact with FAA personnel concerning this special condition in the docket. If you wish us to acknowledge receipt of your comments, you must include a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. SW017.” We will date stamp the postcard and mail it to you.
On September 13, 2004, Bell Helicopter submitted an application for a Type Certificate for the Model 429 helicopter. The Model 429 helicopter is a new design based on the existing drive train of the Bell Model 427 helicopter and a new fuselage. The Model 429 is a twin-engine, 4-bladed main and tail rotor helicopter with a maximum gross weight of 7,000 pounds, capable of carrying up to nine passengers plus a pilot. The helicopter will be designed for dual and single pilot instrument flight rules (IFR) and Category A operations.
Under the provisions of 14 CFR 21.17, Bell Helicopter must show that the Model 429 helicopter meets the applicable provisions of the regulations as listed below:
14 CFR part 27, Amendment 27-0 through Amendment 27-40 dated May 9, 2001.
Sections of 14 CFR part 29, Amendment 29-14 dated September 1, 1977, as listed in 14 CFR part 27 Appendix B for instrument flight rules (IFR).
Sections of 14 CFR part 29 Amendment 29-0 through Amendment 29-47 dated May 9, 2001, as listed in 14 CFR part 27 Appendix C for Category A.
14 CFR part 36 Appendix H, Amendment 36-25, including FAA stage 3 noise limits for helicopters.
In addition to the applicable airworthiness regulations and special conditions, Bell Helicopter Model 429 helicopters must comply with the noise certification requirements of 14 CFR part 36; and the FAA must issue a finding of regulatory adequacy pursuant to § 611 of Public Law 92-574, the “Noise Control Act of 1972.”
Special conditions, as appropriate, are defined in § 11.19, and issued by following the procedures in § 11.38, and become part of the type certification basis in accordance with § 21.17(a)(2).
The Bell Helicopter Model 429 helicopter will incorporate the following novel or unusual design features: Electrical, electronic, or combination of electrical electronic (electrical/electronic) systems that perform critical control functions or provide critical displays, such as electronic flight instruments that will be providing displays critical to the continued safe flight and landing of the helicopter during operation in Instrument Meteorological Conditions (IMC), and Full Authority Digital Engine Control (FADEC) that will be performing engine control functions that are critical to the continued safe flight and landing of the helicopter during visual flight rules (VFR) and IFR operations.
The Bell Helicopter Model 429 helicopter, at the time of application, was identified as incorporating one and possibly more electrical/electronic systems, such as electronic flight instruments and FADEC. After the design is finalized, Bell Helicopter will provide the FAA with a preliminary hazard analysis that will identify any other critical functions, required for safe flight and landing, that are performed by the electrical/electronic systems.
Furthermore, the electromagnetic environment has undergone a transformation not envisioned by the current application of 14 CFR 27.1309(a). Higher energy levels radiate from operational transmitters currently used for radar, radio, and television. Also, the number of transmitters has increased significantly.
The combined effects of the technological advances in helicopter design and the changing environment have resulted in an increased level of vulnerability of the electrical/electronic systems required for the continued safe flight and landing of the helicopter. Effective measures to protect these helicopters against the adverse effects of exposure to HIRF will be provided by the design and installation of these systems. The following primary factors contributed to the current conditions: (1) Increased use of sensitive electronics that perform critical functions; (2) reduced electromagnetic shielding afforded helicopter systems by advanced technology airframe materials; (3) adverse service experience of military aircraft using these technologies; and (4) an increase in the number and power of radio frequency Start Printed Page 73581emitters and the expected increase in the future.
On July 30, 2007, we issued a final HIRL rule (72 FR 44016, August 6, 2007). This rule provides standards to protect aircraft electrical and electronic systems from HIRFs. It was effective September 5, 2007. However, that rule included provisions that provide relief from the new testing requirements for equipment previously certificated under HIRF special conditions issued in accordance with 14 CFR 21.16. To obtain this relief the applicant must be able to show that—
(3) The data used to demonstrate compliance with the HIRF special conditions is provided.
The Bell 429 installations are eligible for this relief provided in 14 CFR 29.1317(d) of the final HIRF rule. However, to meet their HIRF requirements they must comply with this Special Condition, which is based on similar, historical HIRF protections requirements.
The applicant may also demonstrate, by a laboratory test, that the electrical/electronic systems that perform critical control functions or provide critical displays can withstand a peak electromagnetic field strength in a frequency range of 10 kHz to 18 GHz. If a laboratory test is used to show compliance with the defined HIRF environment, no credit will be given for signal attenuation due to installation. A level of 100 volts per meter (v/m) is appropriate for critical display systems. A level of 200 v/m is appropriate for critical control functions. Laboratory test levels are defined according to RTCA/DO-160D Section 20 Category W (100 v/m and 150 mA) and Category Y (200 v/m and 300 mA). As defined in DO-160D Section 20, the test levels are defined as the peak of the root means squared (rms) envelope. As a minimum, the modulations required for RTCA/DO-160D Section 20 Categories W and Y will be used. Other modulations should be selected as the signal most likely to disrupt the operation of the system under test, based on its design characteristics. For example, flight control systems may be susceptible to 3 Hz square wave modulation while the video signals for electronic display systems may be susceptible to 400 Hz sinusoidal modulation. If the worst-case modulation is unknown or cannot be determined, default modulations may be used. Suggested default values are a 1 kHz sine wave with 80 percent depth of modulation in the frequency range from 10 kHz to 400 MHz, and 1 kHz square wave with greater than 90 percent depth of modulation from 400 MHz to 18 GHz. For frequencies where the unmodulated signal would cause deviations from normal operation, several different modulating signals with various waveforms and frequencies should be applied.
Table 2.—Rotorcraft Critical Display Functions Field Strength Volts/Meter
As previously discussed, this special condition is applicable to the Bell Helicopter Model 429 helicopter. Should Bell Helicopter apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, the special condition would apply to that model as well under the provisions of § 21.101.
The substance of this special condition has been subjected to the notice and comment period previously and is written without substantive change from those previously issued. It is unlikely that prior public comment would result in a significant change from the substance contained in this special condition. For this reason, we have determined that prior public notice and comment are unnecessary, and good cause exists for adopting this special condition 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.
Accordingly, pursuant to the authority delegated to me by the Administrator, the following special condition is issued as part of the type certification basis for Bell Helicopter Model 429 helicopters.
1. Each system that performs critical functions must be designed and installed to ensure that the operation and operational capabilities of these critical functions are not adversely affected when the helicopter is exposed to high intensity radiated fields external to the helicopter.
2. For the purpose of this special condition, critical functions are defined as those functions, whose failure would contribute to, or cause, an unsafe condition that would prevent the continued safe flight and landing of the aircraft.
Issued in Fort Worth, Texas, on December 11, 2007.
[FR Doc. E7-25143 Filed 12-27-07; 8:45 am]