[Federal Register Volume 71, Number 146 (Monday, July 31, 2006)]
[Rules and Regulations]
[Pages 43031-43033]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-12139]



 ========================================================================
 Rules and Regulations
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains regulatory documents 
 having general applicability and legal effect, most of which are keyed 
 to and codified in the Code of Federal Regulations, which is published 
 under 50 titles pursuant to 44 U.S.C. 1510.
 
 The Code of Federal Regulations is sold by the Superintendent of Documents. 
 Prices of new books are listed in the first FEDERAL REGISTER issue of each 
 week.
 
 ========================================================================
 

  Federal Register / Vol. 71, No. 146 / Monday, July 31, 2006 / Rules 
and Regulations  

[[Page 43031]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM350, Special Conditions No. 25-320-SC]


Special Conditions: Gulfstream Aerospace Corporation Model G-1159 
Gulfstream II Airplanes; 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 the Gulfstream 
Aerospace Corporation Model G-1159 Gulfstream II airplanes modified by 
Gulfstream Aerospace Corporation, Dallas, Texas. 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 dual electronic attitude direction indicators (ADI) and 
dual horizontal situation indicators (HSI). 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 the Administrator considers necessary to 
establish a level of safety equivalent to that provided by the existing 
airworthiness standards.

DATES: The effective date of these special conditions is July 20, 2006. 
We must receive your comments by August 30, 2006.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM350, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. You may deliver two copies to the Transport 
Airplane Directorate at the address indicated above. You must mark your 
comments Docket No. NM350. You may inspect comments in the Rules Docket 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

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 98055-4056; telephone (425) 227-2799; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment is unnecessary as 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 on 
issuance; however, the FAA invites interested people to take part in 
this rulemaking by sending written comments, data, or views. 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 by the closing date for 
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 May 19, 2006, Gulfstream Aerospace Corporation, Dallas, Texas, 
applied for a supplemental type certificate (STC) to modify the Model 
G-1159 Gulfstream II airplanes. These airplanes are low-wing, 
pressurized transport category airplanes with two fuselage-mounted jet 
engines. They are capable of seating up to 19 passengers, with a crew 
of two pilots. The modification incorporates the installation of dual 
electronic ADI and dual HSI. These systems have a potential to be 
vulnerable to HIRF external to the airplane.

Type Certification Basis

    Under 14 CFR 21.101, Gulfstream Aerospace Corporation must show 
that the Model G-1159 Gulfstream II airplanes, as modified to include 
dual electronic ADI and dual HSI, continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate (TC) No. A12EA or the applicable regulations in effect on 
the date of application for the change. We commonly refer to the 
regulations incorporated by reference in the TC as the ``original type 
certification basis.'' The specific regulations are the Civil Aviation 
Regulations (CAR) 4b, as amended by Amendments 4b-1 through 4b-14.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., CAR 4b as amended) do not contain adequate or 
appropriate safety standards for the Model G-1159 Gulfstream II 
airplanes, because of a novel or unusual design feature, special 
conditions are prescribed under Sec.  21.16.
    Besides the applicable airworthiness regulations and special 
conditions, the Gulfstream Aerospace Corporation Model G-1159 
Gulfstream II airplanes, must comply with the fuel vent exhaust 
emission requirements of 14 CFR part 34. It must also comply with the 
noise certification requirement of 14 CFR part 36.
    We issue special conditions, as defined in 14 CFR part 11.19, under 
Sec.  11.38 and they become part of the type certification basis under 
Sec.  21.101.

[[Page 43032]]

    Special conditions are initially applicable to the model for which 
they are issued. Should Gulfstream Aerospace Corporation apply later 
for an STC to modify any other model included on TC No. A12EA to 
incorporate the same or similar novel or unusual design feature, these 
special conditions would also apply to the other model under Sec.  
21.101.

Novel or Unusual Design Features

    As noted earlier, the modified Model G-1159 Gulfstream II 
airplanes, modified by Gulfstream Aerospace Corporation, will 
incorporate dual electronic ADI and dual HSI that will perform critical 
functions. These systems may be vulnerable to HIRF 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 adverse affects of HIRF. Therefore, we consider these 
systems to be novel or unusual design features.

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 Model G-1159 Gulfstream II airplanes. 
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, and the advent of space and satellite communications 
coupled with electronic command and control of the airplane, the 
immunity of critical digital 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 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 field strengths 
identified in the following table 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
2GHz-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 the 
Model G-1159 Gulfstream II airplanes. Should Gulfstream Aerospace 
Corporation apply later for an STC on another model included on TC 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 the Model G-1159 Gulfstream II airplanes. 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 the special conditions for these airplanes has 
been subjected to the notice and comment procedure in several prior 
instances and has been derived without substantive change from those 
previously issued. 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 immediately. The FAA is requesting comments to allow 
interested people to put in 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.

0
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 the modified Gulfstream 
Aerospace Corporation Model G-1159 Gulfstream II airplanes:
    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.


[[Page 43033]]


    Issued in Renton, Washington, on July 20, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E6-12139 Filed 7-28-06; 8:45 am]
BILLING CODE 4910-13-P