Source: https://www.federalregister.gov/documents/2003/12/09/03-30448/special-conditions-boeing-model-707-300-airplanes-high-intensity-radiated-fields-hirf
Timestamp: 2018-02-20 15:55:30
Document Index: 48199833

Matched Legal Cases: ['§\u200921', 'art 34', 'art 36', '§\u200921', 'art 25', '§\u200921']

Federal Register :: Special Conditions: Boeing Model 707-300 Airplanes; High Intensity Radiated Fields (HIRF)
Special Conditions: Boeing Model 707-300 Airplanes; High Intensity Radiated Fields (HIRF)
A Rule by the Federal Aviation Administration on 12/09/2003
The effective date of these special conditions is December 1, 2003.
68501-68503 (3 pages)
Docket No. NM271, Special Conditions No. 25-254-SC
https://www.federalregister.gov/d/03-30448 https://www.federalregister.gov/d/03-30448
These special conditions are issued for Boeing Model 707-300 airplanes modified by AeroMech Incorporated. 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 dual Innovative Solutions and Support Air Data Display Units. 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 provided by the existing airworthiness standards.
Comments on these special conditions may be mailed in duplicate to: Federal Aviation Administration, Transport Airplane Directorate, Attention: Rules Docket (ANM-113), Docket No. NM271, 1601 Lind Avenue, SW., Renton, Washington, 98055-4056; or delivered in duplicate to the Transport Airplane Directorate at the above address. All comments must be marked: Docket No. NM271.
Greg Dunn, FAA, Airplane and Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, Washington, 98055-4056; telephone (425) 227-2799; facsimile (425) 227-1320.
We will file in the docket all comments we receive, as well as a report summarizing each substantive public contact with FAA personnel concerning these special conditions. The docket is available for public inspection before and after the comment closing date. If you wish to review the docket in person, go to the address in the ADDRESSES section of this preamble Start Printed Page 68502between 7:30 a.m., and 4 p.m., Monday through Friday, except Federal holidays.
On August 29, 2003, AeroMech Incorporated applied to the FAA, Fort Worth Special Certification Office, for a supplemental type certificate (STC) to modify certain Boeing Model 707-300 airplanes. These models are currently approved under Type Certificate No. 4A26. The Model 707-300 is a transport category airplane powered by four Pratt & Whitney turbojet engines. This airplane operates with three flightcrew and can hold up to 189 passengers. The modification incorporates the installation of dual Innovative Solutions and Support (IS&S) Air Data Display Units. The information presented is flight critical. The avionics/electronics and electrical systems installed in this airplane have the potential to be vulnerable to high-intensity radiated fields (HIRF) external to the airplane.
Under the provisions of 14 CFR 21.101, AeroMech Incorporated must show that the Boeing Model 707-300 airplanes, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. 4A26, 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 certification basis for the Model 707-300 airplanes includes Civil Air Regulations (CAR) 4b, as amended by Amendments 4b-1, 4b-2, and 4b-3; and additional requirements identified in the type certificate data sheet that are not relevant to these special conditions.
If the Administrator finds that the applicable airworthiness regulations (CAR 4b, as amended) do not contain adequate or appropriate safety standards for the Boeing Model 707-300 airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
In addition to the applicable airworthiness regulations and special conditions, the Boeing Model 707-300 airplanes 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 are initially applicable to the model for which they are issued. Should AeroMech Incorporated apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate 4A26 to incorporate the same or similar novel or unusual design feature, these special conditions would also apply to the other model under the provisions of § 21.101.
As noted earlier, Boeing Model 707-300 airplanes modified by AeroMech Incorporated will incorporate brand new avionics/electronics and electrical systems (IS&S Air Data Display Units) that will perform critical functions. These systems may be vulnerable to high-intensity radiated fields external to the airplane. The current airworthiness standards of part 25 do not contain adequate or appropriate safety standards for the protection of this equipment from the adverse effects of HIRF. Accordingly, this sytem is considered to be a novel or unusual design feature.
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 Boeing Model 707-300 airplanes modified by AeroMech Incorporated. These special conditions require that new avionics/electronics and electrical systems 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.
With the trend toward increased power levels from ground-based transmitters, and 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.
10 kHz-100 kHz 50
100 kHz-500 kHz 50
500 kHZ-2 MHz 50
2 MHz-30 MHz 100
30 MHz-70 MHz 50
70 MHz-100 MHz 50
100 MHz-200 MHz 100
200 MHz-400 MHz 100
400 MHz-700 MHz 700
700 MHz-1 GHz 700
1 GHz-2 GHz 2000
2 GHz-4 GHz 3000
4 GHz-6 GHz 3000
6 GHz-8 GHz 1000
8 GHz-12 GHz 3000
12 GHz-18 GHz 2000
18 GHz-40 GHz 600
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 Start Printed Page 68503Working Group of the Aviation Rulemaking Advisory Committee.
As discussed above, these special conditions are applicable to Boeing Model 707-300 series airplanes modified by AeroMech Incorporated. Should AeroMech Incorporated apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate 4A26 to incorporate the same or similar novel or unusual design feature, these special conditions would apply to that model as well as under the provisions of § 21.101.
This action affects only certain novel or unusual design features on the Boeing Model 707-300 airplanes modified by AeroMech Incorporated. 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.
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 707-300 airplanes modified by AeroMech Incorporated.
[FR Doc. 03-30448 Filed 12-8-03; 8:45 am]