[Federal Register Volume 60, Number 105 (Thursday, June 1, 1995)]
[Proposed Rules]
[Pages 28550-28551]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-13400]



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


DEPARTMENT OF TRANSPORTATION
14 CFR Part 25

[Docket No. NM-109; Notice No. SC-95-3-NM]


Special Condition: Gulfstream Aerospace Corporation, Model 
Gulfstream V, High-Intensity Radiated Fields

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed special conditions.

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

SUMMARY: This notice proposes special conditions for the Gulfstream 
Model Gulfstream V airplane. This new airplane will utilize new 
avionics/electronic systems that provide critical data to the 
flightcrew. The applicable regulations do not contain adequate or 
appropriate safety standards for the protection of these systems from 
the effects of high-intensity radiated fields. These proposed 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: Comments must be received on or before July 17, 1995.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Office of the Assistant Chief Counsel, 
Attn: Rules Docket (ANM-7), Docket No. NM-109, 1601 Lind Avenue SW., 
Renton, Washington 98055-4056; or delivered in duplicate to the Office 
of the Assistant Chief Counsel at the above address. Comments must be 
marked: Docket No. NM-109. 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:
Standardized Branch, ANM-113, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW., Renton, Washington 98055-
4056.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting such written data, 
views, or arguments as they may desire. Communications should identify 
the regulatory docket or notice 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 
before further rulemaking action is taken on these proposals. The 
proposals contained in this notice may be changed in light of comments 
received. All comments submitted 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. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM-109.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On February 26, 1992, Gulfstream Aerospace Corporation, P.O. Box 
2206, Savannah, GA 31402-2206, applied for an amended type certificate 
in the transport airplane category for the Model Gulfstream V airplane. 
The Gulfstream V is a T-tail, low swept wing, business jet airplane 
powered by two Rolls-Royce BR710-48 turbofan engines mounted on pylons 
extending from the aft fuselage. Each engine will be capable of 
delivering 14,750 pounds trust. The flight controls will be powered and 
capable of manual reversion. The airplane has a seating capacity of up 
to nineteen passengers, and a maximum takeoff weight of 89,000 pounds.
Type Certification Basis

    Under the provisions of Sec. 21.17 of the FAR, Gulfstream must 
show, except as provided in Sec. 25.2, that the Model Gulfstream V 
meets the applicable provisions of part 25, effective February 1, 1965, 
as amended by Amendments 25-1 through 25-75. In addition, the proposed 
certification basis for the Model Gulfstream V includes part 34, 
effective September 10, 1990, plus any amendments in effect at the time 
of certification; and part 36, effective December 1, 1969, as amended 
by Amendment 36-1 through the amendment in effect at the time of 
certification. No exemptions are anticipated. The special conditions 
that may be developed as a result of this notice will form an 
additional part of the type certification basis. In addition, the 
certification basis may include other special conditions that are not 
relevant to these proposed special conditions.
    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 V because of a novel or 
unusual design feature, special conditions are prescribed under the 
provisions of Sec. 21.16 to establish a level of safety equivalent to 
that established in the regulations.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28 
and 11.29, and become part of the type certification basis in 
accordance with Sec. 21.17(a)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporated the same novel or 
unusual design feature, or should any other model already included on 
the same type certicate be modified to incorporate the same novel or 
unusual design feature, the special conditions would also apply to the 
other model under the provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The Model Gulfstream V incorporates new avionic/electronic 
installations, including a digital Electronic Flight Instrument System 
(EFIS), Air Data System, Attitude and Heading Reference System (AHRS), 
Navigation and Communication System, Autopilot System, and a Full 
Authority Digital Engine Control (FADEC) system that controls critical 
engine parameters. These systems may be vulnerable to high-intensity 
radiated fields external to the airplane.

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 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 equivalent to that 
intended by the regulations incorporated by reference, special 
conditions are proposed for the Gulfstream V which would require that 
new technology electrical and electronic systems, such as the EFIS, 
FADEC, AHRS, etc., be designed and installed to preclude component 
damage and interruption of [[Page 28551]] 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 digital avionics 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 paragraphs 1 or 2 below:
    1. A minimum threat of 100 volts per meter peak 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.

------------------------------------------------------------------------
                                                       Peak(V/   Average
                      Frequency                          M)       (V/M) 
------------------------------------------------------------------------
10 KHz-100 KHz......................................        50        50
100 KHz-500 KHz.....................................        60        60
500 KHz-2000 KHz....................................        70        70
2 MHz-30 MHz........................................       200       200
30 MHz-70 MHz.......................................        30        30
70 MHz-100 MHz......................................        30        30
100 MHz-200 MHz.....................................       150        33
200 MHz-400 MHz.....................................        70        70
400 MHz-700 MHz.....................................     4,020       935
700 MHz-1000 MHz....................................     1,700       170
1 GHz-2 GHz.........................................     5,000       990
2 GHz-4 GHz.........................................     6,680       840
4 GHz-6 GHz.........................................     6,850       310
6 GHz-8 GHz.........................................     3,600       670
8 GHz-12 GHz........................................     3,500     1,270
12 GHz-18 GHz.......................................     3,500       360
18 GHz-40 GHz.......................................     2,100       750
------------------------------------------------------------------------

    As discussed above, the proposed special conditions would be 
applicable initially to the Model Gulfstream V. Should Gulfstream apply 
at a later date for a change to the type certificate to include another 
model incorporating the same novel or unusual design feature, the 
special conditions would apply to that model as well, under the 
provisions of Sec. 21.101(a)(1).

Conclusion

    This action affects certain design features only on the Gulfstream 
V airplane. It is not a rule of general applicability and affects only 
the manufacturer who applied to the FAA for approval of these features 
on the airplane.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Federal Aviation Administration, 
Reporting and recordkeeping requirements.

    The authority citation for these proposed special conditions is as 
follows:

    Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355, 
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et 
seq.; E.O. 11514; and 49 U.S.C. 106(g).

The Proposed Special Condition

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the Gulfstream Model Gulfstream V series 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 this 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 May 17, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 95-13400 Filed 5-31-95; 8:45 am]
BILLING CODE 4910-13-M