Federal Aviation Administration (FAA), DOT.
Final special conditions; request for comments.
These special conditions are issued for Boeing Model 747-300 series airplanes modified by Honeywell Start Printed Page 8163International, Inc. These modified airplanes will have novel or unusual design features associated with the installation of new navigation management system that includes electronic flight instrument system (EFIS) displays. The EFIS displays will use 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 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.
The effective date of these special conditions is January 16, 2001. Comments must be received on or before March 1, 2001.
Comments on these special conditions may be mailed in duplicate to: Federal Aviation Administration, Transport Airplane Directorate, Attention: Rules Docket (ANM-114), Docket No. NM182, 1601 Lind Avenue SW., Renton, Washington 98055-4056; or delivered in duplicate to the Transport Airplane Directorate at that address. All comments must be marked: “Docket No. NM182.” Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4:00 p.m.Start Further Info
FOR FURTHER INFORMATION CONTACT:
For information concerning the certification program for the Boeing Model 747-300 series airplanes modified by Honeywell International, Inc., contact: Ross Landes, Standardization Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-145; fax (425) 227-1149.
For information on the general subject of HIRF, contact: Massoud Sadeghi, Federal Aviation Administration, Transport Airplane Directorate, Airplane and Flight Crew Interface Branch, ANM-111, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-2117; fax (425) 227-1320.End Further Info End Preamble Start 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.
Although these special conditions are being issued as final special conditions without prior public notice, interested persons are invited to submit such written data, views, or arguments as they may desire. Communications should identify the regulatory docket 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. 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. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to these special conditions must include a self-addressed, stamped postcard on which the following statement is made: “Comments to NM182.” The postcard will be date stamped and returned to the commenter.
On October 20, 2000, Honeywell International Inc., 15001 N.E. 36th Street, P.O. Box 97001, Redmond, Washington 98073-9701, applied for a Supplemental Type Certificate (STC) for the Boeing Model 747-300 series airplanes operated by South African Airways (SAA). Honeywell plans to install upgraded avionics equipment on these airplanes. This equipment includes an electronic flight instrument system (EFIS) that displays attitude and heading information, and is manufactured by Astronautics. The modified airplanes are scheduled for certification in January 2001.
The Astronautics EFIS provides a critical function that displays attitude and heading information. The EFIS must be designed and installed to ensure that its operation is not adversely affected by high intensity radiated fields (HIRF). These functions can be susceptible to disruption of both command and response signals as a result of electrical and magnetic interference caused by HIRF external to the airplane. This disruption of signals could result in loss of critical flight displays and annunciations, or could present misleading information to the pilot.
The subject Boeing Model 747-300 series airplanes are four-engine transport category airplanes with a wingspan of 195 ft. 8 in. (59.6 m) and an overall length of 231 ft. 10.2 in. (70.6 m). They are essentially identical to the earlier Model 747-200 series, but have a stretched upper deck. Their maximum takeoff weight is 833,000 lbs. (374,850 kg) and typical cruise speed at 35,000 feet is Mach 0.85/565 mph (910 km/h)
Type Certification Basis
Under the provisions of 14 CFR 21.101, Honeywell must show that the Boeing Model 747-300 series airplanes, as modified, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. A20WE, or the applicable regulations in effect on the date of application for the modification. 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. A20WE for the Boeing Model 747-300 series airplanes are as follows:
- 14 CFR parts 1, 21, 34 (fuel vent and exhaust emission requirements), and 36 (noise certification requirements).
- 14 CFR part 25, effective February 1, 1965.
- Amendments 25-1 through 25-8, plus 25-15, 25-17, 25-18, 25-20, and 25-39 (transmitted by FAA letter dated February 4, 1977).
- Amendment 25-36, re: RB211 engine oil filter system compliance with § 25.1019 and § 25.1305(c)(7).
- Amendment 25-46, § 25.803(d) (Transmitted by FAA letter to The Boeing Company, dated September 2, 1983. This is limited to all passenger configurations and 6/7 palet combi configurations.)
2. Special Conditions
- Special conditions summarized for record purposes as enclosed with FAA letter to The Boeing Company dated February 20, 1970.
- Special Conditions 4A, revised to apply to airplanes with the landing gear load evener system deleted (recorded as attachment to an FAA letter to The Boeing Company dated May 12, 1971).
- Special Conditions No. 25-61-NW-1 for occupancy not to exceed 32 passengers on the upper deck of airplanes with spiral staircase Start Printed Page 8164(transmitted to The Boeing Company by FAA letter dated February 26, 1975).
- Special Conditions No. 25-71-NW-3 for occupancy not to exceed 45 passengers on the upper deck of airplanes with straight segmented stairway (transmitted to The Boeing Company by FAA letter dated September 8, 1976).
- Modification of Special Conditions No. 25-71-NW-3 for occupancy not to exceed 110 passengers on the upper deck of airplanes with segmented stairway (transmitted to The Boeing Company by FAA letter dated August 3, 1981).
- Special Conditions No. 25-77-NW-4—modification of the autopilot system to approve the airplane for use of the system under category IIIb landing conditions (transmitted to The Boeing Company by FAA letter dated July 8, 1977).
- Special Condition No. 25-ANM-16 for installation of an overhead crew rest area, occupancy not to exceed 10 crewmembers. (The FAA-approved procedures required for compliance with paragraph 13 of the Special Condition are located in Boeing Document D926U303, Appendix D.)
3. Exemptions From 14 CFR Part 25
- Exemption No. 1013A, dated December 24, 1969.
- Exemption No. 1870D, dated April 3, 1991.
- Exemption No. 3035 dated September 9, 1980.
4. Compliance With the Following Optional Requirements
- § 25.801, “Ditching.”
- § 25.1419, “Ice protection.”
5. Equivalent Safety Findings With Respect to the Following Regulations
- § 25.773(b)(2)(i), amendments 25-1 through 25-67, “Pilot compartment view.”
- § 25.811(f), “Emergency exit marking.”
- § 25.812(k)(2), “Emergency lighting.”
- § 25.815, “Width of aisle.”
- § 25.1415(d) “Ditching equipment” [re: Emergency Locator Transmitter (ELT)].
If the Administrator finds that the applicable airworthiness regulations (i.e., 14 CFR part 25, as amended) do not contain adequate or appropriate safety standards for the Boeing Model 747-300 series airplanes modified by Honeywell because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
Special conditions, as appropriate, are issued in accordance with § 11.19, as required by § 11.38, and become part of the airplane's type certification basis in accordance with § 21.101(b)(2).
The special conditions approved in this new document will form an additional part of the type certification basis for these airplanes.
Special conditions are initially applicable to the model for which they are issued. Should Honeywell 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 § 21.101(a)(1).
Novel or Unusual Design Features
The Boeing Model 747-300 series airplanes modified by Honeywell will incorporate the Astronautics EFIS system, which performs critical functions. The EFIS system contains electronic equipment for which the current 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. This system may be vulnerable to HIRF external to the airplane. Accordingly, this system is considered to be a novel or unusual design feature.
There is no specific regulation that addresses the requirements for protection of 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 that is equivalent to that intended by the regulations incorporated by reference, special conditions are needed for the Boeing Model 747-300 airplanes modified by Honeywell to include the Astronautics EFIS system. These special conditions will require that this system, which performs 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, and the use of composite material in the airplane structure, 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 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, alternatively, 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.
2. A threat external to the airframe for both of the following field strengths for the frequency ranges indicated. Both peak and average field strength components from Table 1 are to be demonstrated.
|Frequency||Field Strength (volts per meter)|
|10 kHz-100 kHz||50||50|
|100 kHz-500 kHz||50||50|
|500 kHz-2 MHz||50||50|
|2 MHz-30 MHz||100||100|
|30 MHz-70 MHz||50||50|
|70 MHz-100 MHz||50||50|
|100 MHz-200 MHz||100||100|
|200 MHz-400 MHz||100||100|
|400 MHz-700 MHz||700||50|
|700 MHz-1 GHz||700||100|
|1 GHz-2 GHz||2000||200|
|2 GHz-4 GHz||3000||200|
|4 GHz-6 GHz||3000||200|
|6 GHz-8 GHz||1000||200|
|8 GHz-12 GHz||3000||300|
|12 GHz-18 GHz||2000||200|
|18 GHz-40 GHz||600||200|
|The field strengths are expressed in terms of peak of the root-mean-square (rms) over the complete modulation period.|
The threat levels identified in Table 1 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. Start Printed Page 8165
As discussed above, these special conditions are applicable to the Boeing Model 747-300 series airplanes modified by Honeywell International, Inc., to include the Astronautics EFIS system. Should Honeywell apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate A20WE to incorporate the same novel or unusual design features, these special conditions would apply to that model as well under the provisions of § 21.101(a)(1).
This action affects only certain novel or unusual design features on the Boeing Model 747-300 series airplanes modified by Honeywell International, Inc. 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.
As stated previously, the substance of the 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. 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.Start List of Subjects
List of Subjects in 14 CFR Part 25End List of Subjects
The authority citation for these special conditions is as follows:
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 Boeing Model 747-300 series airplanes modified by Honeywell International, Inc.
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.Start Signature
Issued in Renton, Washington, on January 16, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 01-2037 Filed 1-29-01; 8:45 am]
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