[Federal Register Volume 72, Number 6 (Wednesday, January 10, 2007)]
[Rules and Regulations]
[Pages 1137-1139]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-197]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM363; Special Conditions No. 25-344-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: The FAA issues these special conditions for a Gulfstream 
Aerospace Corporation Model G-1159A airplane modified by AeroMech 
Incorporated. This modified airplane 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 Innovative Solutions and 
Support integrated air data display units (ADDU). These systems 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.

DATES: The effective date of these special conditions is December 29, 
2006. We must receive your comments on or before February 9, 2007.

ADDRESSES: You may mail or deliver comments on these special conditions 
in duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-113), Docket No. NM363, 1601 
Lind Avenue, SW., Renton, Washington 98057-3356. You must mark your 
comments Docket No. NM363.

FOR FURTHER INFORMATION CONTACT: Greg Dunn, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 227-2799; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment for these special conditions is impracticable because these 
procedures would significantly delay certification and 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. We therefore 
find that good cause exists for making these special conditions 
effective upon issuance. However, we invite interested persons to take 
part in this rulemaking by submitting written comments. The most 
helpful comments reference a specific portion of the special 
conditions, explain the reason for any recommended change, and include 
supporting data. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
about these special conditions. You may inspect the docket 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 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive on or before the closing 
date for

[[Page 1138]]

comments. We will consider comments filed late if it is possible to do 
so without incurring expense or delay. We may change these special 
conditions based on the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, include with your comments a pre-addressed, 
stamped postcard on which the docket number appears. We will stamp the 
date on the postcard and mail it back to you.

Background

    On September 29, 2006, AeroMech Incorporated, 1616 Hewitt Avenue, 
Suite 312, Everett, Washington 98201, applied for a supplemental type 
certificate (STC) to modify a Gulfstream Aerospace Corporation model G-
1159A airplane. The Gulfstream Aerospace Corporation Model G-1159A 
airplane is a small transport category airplane powered by two turbine 
engines. It operates with a 2-pilot crew and can seat up to 15 
passengers. The modification incorporates the installation of 
Innovative Solutions and Support integrated air data display units. 
These systems have a 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, AeroMech Incorporated must 
show that Gulfstream Aerospace Corporation Model G-1159A airplane, as 
changed, continues 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 specific regulations are 14 CFR part 25 as 
amended by Amendments 25-1 through 25-8, 25-10, 25-12, 25-16 through 
25-22, 25-24, 25-26, 25-27, 25-29 through 25-34, 25-37, 25-40 (as 
applicable to a new APU installation); Sec.  25.1309 as amended by 
Amendment 25-41, and Sec.  25.1329 (as applied to a new autopilot 
installation), Sec.  25.994 (crashworthiness fuel system components), 
and Sec.  25.581 (lightning protection), as amended by Amendment 25-23; 
and Special part 27, as amended by Amendment 27-2 (fuel venting 
emission). The special conditions contained in the FAA's letter to 
Grumman dated September 27, 1965, applicable to the Gulfstream Model G-
1159 airplane, are also applicable to the Gulfstream Model G-1159A 
airplane, except that reference to Civil Air Regulations 4b.450 in the 
``Cooling Systems'' special conditions is replaced by Sec.  25.1043, 
effective February 1, 1965. In addition, the special conditions 
pertaining to dynamic gust loads contained in the FAA AEA-212 letter 
dated July 22, 1980.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25, as amended) do not contain adequate or 
appropriate safety standards for the Gulfstream Aerospace Corporation 
Model G-1159A airplane because of a novel or unusual design feature, 
special conditions are prescribed under Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, Gulfstream Aerospace Corporation Model G-1159A 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.
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38, and they become part of the type certification basis under 
the provisions of Sec.  21.101.

Novel or Unusual Design Features

    As noted earlier, Gulfstream Aerospace Corporation G-1159A airplane 
modified by AeroMech Incorporated will incorporate Innovative Solutions 
and Support integrated air data display units that will perform 
critical functions. These systems may be vulnerable to high-intensity 
radiated fields external to the airplane. Current airworthiness 
standards of part 25 do not contain adequate or appropriate safety 
standards for protecting this equipment from adverse effects of HIRF. 
So 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 equivalent to that 
intended by the regulations incorporated by reference, special 
conditions are needed for the Gulfstream Aerospace Corporation G-1159A 
airplane 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 because of HIRF.

High-Intensity Radiated Fields (HIRF)

    High-power radio frequency transmitters for radio, radar, 
television, and satellite communications can adversely affect operation 
of airplane electric and electronic systems. Therefore, the immunity of 
critical avionics/electronics and electrical systems to HIRF must be 
established.
    Based on surveys and analysis of existing HIRF emitters, an 
adequate level of protection exists when airplane system immunity is 
demonstrated when exposed to the HIRF environments in 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. System elements and their associated wiring harnesses must be 
exposed to the environment without benefit of airframe shielding.
    b. Demonstration of this level of protection is established through 
system tests and analysis.
    2. An environment external to the airframe of the field strengths 
shown in the table below for the frequency ranges indicated. Immunity 
to both peak and average field strength components from the table must 
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 environmental levels identified above are the result of an FAA 
review of existing studies on the subject of HIRF and of the work of 
the Electromagnetic Effects Harmonization Working Group of the Aviation 
Rulemaking Advisory Committee.

Applicability

    These special conditions are applicable to a Gulfstream Aerospace

[[Page 1139]]

Corporation Model G-1159A airplane modified by AeroMech Incorporated. 
Should AeroMech Incorporated apply at a later date for a supplemental 
type certificate to modify any other similar model included on Type 
Certificate No. A12EA to incorporate the same or similar novel or 
unusual design feature, these special conditions would apply to that 
model as well under Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on a Gulfstream Aerospace Corporation Model G-1159A airplane 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.

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

    Therefore, under the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the supplemental type certification basis for the Gulfstream Aerospace 
Corporation Model G-1159A airplane modified by AeroMech Incorporated.
    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 December 29, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-197 Filed 1-9-07; 8:45 am]
BILLING CODE 4910-13-P