[Federal Register Volume 66, Number 216 (Wednesday, November 7, 2001)]
[Rules and Regulations]
[Pages 56195-56197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-27987]



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  Federal Register / Vol. 66, No. 216 / Wednesday, November 7, 2001 / 
Rules and Regulations  

[[Page 56195]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM201; Special Conditions No. 25-190-SC]


Special Conditions: Gulfstream Aerospace Corporation Model G-
1159B; High-Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued for Gulfstream Aerospace 
Corporation Model G-1159B airplanes modified by ElectroSonics. 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 Dual Airdata Computer 
System that performs 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.

DATES: The effective date of these special conditions is October 24, 
2001. Comments must be received on or before December 7, 2001.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-113), Docket No. NM201, 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. NM201. Comments may be 
inspected in the Rules Docket weekdays, except Federal holidays, 
between 7:30 a.m. and 4:00 p.m.

FOR FURTHER INFORMATION CONTACT: Meghan Gordon, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(425) 227-2138; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that good cause exists for making these 
special conditions effective upon issuance; however, 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. 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 self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. NM201.'' The postcard will be date stamped and returned 
to the commenter.

Background

    On April 4, 2001, ElectroSonics, 4391 International Gateway, 
Columbus, Ohio, applied for a Supplemental Type Certificate (STC) to 
modify Gulfstream Aerospace Corporation Model G-1159B airplanes. The 
Gulfstream Aerospace Corporation Model G-1159B is a small transport 
category airplane. These airplanes are powered by two Rolls Royce Spey 
RB (163-25) 511-8 engines, with a maximum takeoff weight of 69,700 
pounds. This airplane operates with a 2-pilot crew and can hold up to 
19 passengers. The modification incorporates the installation of a 
Honeywell Dual Airdata Computer System. The Honeywell Dual Airdata 
Computer System is a replacement for the existing Analog Flight 
Instrumentation, while also providing additional functional capability 
and redundancy in the system. 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.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, ElectroSonics must show that 
the Gulfstream Aerospace Corporation Model G-1159B 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 in the certification basis for 
the Gulfstream Aerospace Corporation G-1159B airplanes include:
     Civil Air Regulations (CAR) 4b, dated December 31, 1953, 
including Amendments 4b-1 thru 4b-14.
     Special Regulation SR450A.
     Special Conditions in ``Attachment A'' of FAA letter to 
Grumman dated September 27, 1965.
     14 CFR (Code of Federal Regulations) 25.1325 ( effective 
February 1, 1965).
     Section 25.175 (effective March 1, 1965), in lieu of CAR 
4b.155(b).
     Section 36.7(d)(3)(ii).
     CAR 4b.450, cooling systems.
     Part 25, dated February 1, 1965, as amended by Amendments 
No. 25-2 through 25-8, 25-10, 25-12, 25-16 thru 25-22, 25-24, and 25-
26.
    If the Administrator finds that the applicable airworthiness 
regulations (part 25, as amended) do not contain adequate or 
appropriate safety standards for the Gulfstream Aerospace Corporation 
Model G-1159B airplanes modified by ElectroSonics, because of a novel 
or unusual design feature, special

[[Page 56196]]

conditions are prescribed under the provisions of 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, these Gulfstream Aerospace Corporation Model G-1159B 
airplanes must comply with the fuel vent and exhaust emission 
requirements of part 34 and the noise certification requirements of 
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 ElectroSonics apply at a later date 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

    As noted earlier, the Gulfstream Aerospace Corporation Model G-
1159B airplanes modified by ElectroSonics will incorporate the 
Honeywell Dual Airdata Computer System that will perform critical 
functions. This system 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 system is 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 ground-based radio transmitters and the growing use 
of sensitive avionics/electronics 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 that is equivalent to 
that intended by the regulations incorporated by reference, special 
conditions are needed for the Gulfstream Aerospace Corporation Model G-
1159B airplanes modified by ElectroSonics. 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.

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, 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 in accordance with either paragraph 1 or 2 below:
    1. A minimum threat of 100 volts rms (root-mean-square) 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 meter)
                   Frequency                   -------------------------
                                                    Peak       Average
------------------------------------------------------------------------
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 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 
Gulfstream Aerospace Corporation Model G-1159B airplanes modified by 
ElectroSonics. Should ElectroSonics apply at a later date 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 apply to that model as well 
under the provisions of Sec. 21.101(a)(1).

[[Page 56197]]

Conclusion

    This action affects only certain novel or unusual design features 
on Gulfstream Aerospace Corporation Model G-1159B airplanes modified by 
ElectroSonics. 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 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. 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 supplemental type certification basis for Gulfstream Aerospace 
Corporation Model G-1159B airplanes modified by ElectroSonics.
    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.

    Issued in Renton, Washington, on October 24, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-27987 Filed 11-6-01; 8:45 am]
BILLING CODE 4910-13-P