[Federal Register Volume 60, Number 157 (Tuesday, August 15, 1995)]
[Rules and Regulations]
[Pages 42029-42031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20151]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-116; Special Condition No. 25-ANM-104]


Special Condition: Israel Aircraft Industries (IAI), Model Astra 
SPX, High-Intensity Radiated Fields

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special condition; request for comments.

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SUMMARY: This special condition is issued for the Israel Aircraft 
Industries (IAI) Model Astra SPX airplane. This new airplane utilizes 
new avionics/electronic systems, such as electronic displays and 
electronic engine controls, that perform critical functions. 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 (HIRF). This special condition contains 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 this special condition is July 26, 1995. 
Comments must be received on or before September 14, 1995

ADDRESSES: Comments on this special condition may be mailed in 
duplicate to: Federal Aviation Administration, Office of the Assistant 
Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-116, 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-116. 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: Timothy Dulin, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4506; 
telephone (206) 227-2141.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA has determined that good cause exists for making this 
special condition 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 and 
special condition 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. This special 
condition may be changed in light of the 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 

[[Page 42030]]
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 request must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM-116.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On February 15, 1994, Israel Aircraft Industries (IAI), Ben Gurion 
International Airport, Tel Aviv 70100, Israel, applied for an amendment 
to Type Certificate (TC) A16NM to incorporate the Model Astra SPX 
airplane. The Astra SPX is a derivative of the Model 1125 Westwind 
Astra. The changes include installation of new Allied Signal (Garrett) 
TFE731-40/40A engines, which are a derivative of the existing TFE731-
3A-200G engines; installation of winglets and minor structural 
modifications to the wing; and installation of new avionics.

Type Certification Basis

    Under the provisions of Sec. 21.101 of 14 CFR part 21, IAI must 
show that the Model Astra SPX meets the applicable regulations 
incorporated by reference in TC A16NM, 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 
incorporate by reference in TC A16NM are as follows: Part 25, effective 
February 1, 1965, as amended by Amendments 25-1 through 25-54. The 
regulations in effect on the date of application include the applicable 
provisions of part 25 effective February 1, 1965, as amended by 
Amendments 25-1 through 25-79. In addition, the certification basis for 
the Model Astra SPX 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. This special 
condition will form an additional part of the type certification basis. 
In addition, the certification basis may include exemptions and other 
special conditions that are not relevant to this special condition.
    If the Administrator finds that the applicable airworthiness 
regulation (i.e., part 25, as amended) do not contain adequate or 
appropriate safety standards for the Astra SPX 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. 21.101(b)(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 incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate 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 Astra SPX incorporates new avionic/electronic systems, 
such as electronic displays and electronic engine controls, that 
perform critical functions. These systems may be vulnerable to HIRF 
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, a special 
condition is needed for the IAI Astra SPX, which would require that new 
electrical and electronic 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 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.

------------------------------------------------------------------------
                                                              Average(V/
                    Frequency                      Peak(V/M)      M)    
------------------------------------------------------------------------
10 KHz-100 KHz...................................         50          50
100 KHz-500 KHz..................................         60          60
500 KHz-2 MHz....................................         70          70
2 MHz-30 MHz.....................................        200         200
30 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-1 GHz....................................      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, this special condition would be applicable 
initially to the IAI Model Astra SPX. Should IAI apply at a later date 
for a change to the type certificate to include another model 
incorporating the same novel or unusual design feature, this special 
condition would apply to that model as well, under the provisions of 
Sec. 21.101(a)(1).

Conclusion

    This action affects only certain design features on the IAI Astra 
SPX 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.
    The substance of the special condition for this airplane has been 
subjected to the notice and comment procedure 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 

[[Page 42031]]
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 this special condition immediately. Therefore, this special 
condition is being made effective 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 this special condition is as follows:

    Authority: 49 U.S.C. app. 1344, 1354(a), 1355, 1421, 1423, 1424, 
1425, 1428, 1429, 1430, and 49 U.S.C. 106(g).

The Special Condition

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special condition is issued as part of the 
type certification basis for the Israel Aircraft Industries (IAI) Model 
Astra SPX 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 condition, 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 July 26, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-20151 Filed 8-14-95; 8:45 am]
BILLING CODE 4910-13-M