[Federal Register Volume 68, Number 159 (Monday, August 18, 2003)]
[Rules and Regulations]
[Pages 49332-49334]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-21106]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM261; Special Conditions No. 25-243-SC]


Special Conditions: Israel Aircraft Industries Model 1124 
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 Israel Aircraft 
Industries Model 1124 airplanes modified by Avionics Certification 
Services. 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 dual Innovative 
Solutions and Support Air Data Display Unit system that performs 
critical functions. The applicable airworthiness regulations do not 
contain adequate or appropriate safety standards for the protection of 
this system 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 August 7, 
2003. Comments must be received on or before September 17, 2003.

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. NM261, 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. NM261.

FOR FURTHER INFORMATION CONTACT: Steven R. Edgar, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(425) 227-2025; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment is impracticable because these procedures would significantly 
delay certification of the airplane and thus 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. The FAA therefore finds that 
good cause exists for making these special conditions effective upon 
issuance; however, the FAA invites interested persons to participate in 
this rulemaking by submitting 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 
concerning these special conditions. The docket is available for public 
inspection 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 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 February 1, 2003, Avionics Certification Services, 1675 
Turnberry Drive, San Marcos, California, applied for a Supplemental 
Type Certificate (STC) to modify Israel Aircraft Industries Model 1124 
airplanes. These models are currently approved under Type Certificate 
No. A2SW. The Model 1124 is a transport category airplane powered by 
two Garrett AiResearch TFE-731-3-1G turbofan engines and has a maximum 
takeoff weight of 23,500 pounds. This airplane operates with a 2-pilot 
crew and can hold up to 10 passengers. The modification incorporates 
the installation of a dual Innovative Solutions and Support Air Data 
Display Unit (ADDU) system. The ADDU system is a replacement for the 
pneumatic altimeters. 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, Avionics Certification 
Services must show that the Israel Aircraft Industries Model 1124, as 
changed, continues to meet the applicable provisions of the regulations 
incorporated by reference in Type Certificate No. A2SW, or the 
applicable regulations in effect on the date of

[[Page 49333]]

application for the change. The regulations incorporated by reference 
in the type certificate are commonly referred to as the ``original type 
certification basis.'' The certification basis for the Model 1124 
airplanes includes 14 CFR 21.29; CAR 4b effective December 31, 1953, 
including amendments 4b-1 through 4b-11, and 4b-12; paragraphs 
4b.132(e), 4b.151(a), 4b.155, 4b.156, 4b.157, 4b.158, 4b.160, 4b.162, 
4b.191, 4b.210(b)(5), 4b.603(k); 4b.711; and paragraphs pertaining to 
engine fire shielding. In addition, the certification basis includes 
Special Regulations (SR) SR 422b, effective July 9, 1959; SR 450A, 
effective August 31, 1962; Sec.  25.771 as amended by Amendment 25-4; 
Sec.  25.2 as amended by Amendments 25-15, 25-17, and 25-20; Sec.  
33.97, as amended by Amendment 33-3, and Sec.  33.99; Special 
Conditions specified in FAA letters of December 13, 1963, and June 2, 
1964; Special Conditions 25-37-EU-8, dated November 16, 1971; and 
Special FAR 27 effective January 1, 1974; and the following 14 CFR part 
25 sections, as amended by Amendments 25-1 through 25-34, which 
replaced the corresponding CAR 4b paragraphs: Sec. Sec.  25.831 through 
25.843, 25.901 through 25.1203, 25.1305, 25.1521, and 25.1309 with 
respect to reverse thrust installation.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., CAR 4b or part 25, as amended) do not contain 
adequate or appropriate safety standards for the Israel Aircraft 
Industries Model 1124 airplanes because of a novel or unusual design 
feature, special conditions are prescribed under the provisions of 
Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Israel Aircraft Industries Model 1124 airplanes 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.
    Special conditions, as defined in 14 CFR 11.19, are issued in 
accordance with Sec.  11.38 and become part of the type certification 
basis in accordance with Sec.  21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should Avionics Certification Services apply at a 
later date for a supplemental type certificate to modify any other 
model included on Type Certificate No. A2SW to incorporate the same or 
similar novel or unusual design feature, these special conditions would 
also apply to the other model.

Novel or Unusual Design Features

    As noted earlier, the Israel Aircraft Industries Model 1124 
airplanes modified by Avionics Certification Services will incorporate 
a dual Air Data Unit Display 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 equivalent to that 
intended by the regulations incorporated by reference, special 
conditions are needed for the Israel Aircraft Industries Model 1124 
airplanes modified by Avionics Certification Services. 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 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 table below 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

[[Page 49334]]

 
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 
Israel Aircraft Industries Model 1124 airplanes modified by Avionics 
Certification Services. Should Avionics Certification Services apply at 
a later date for a supplemental type certificate to modify any other 
model included on Type Certificate No. A2SW to incorporate the same or 
similar novel or unusual design feature, these special conditions would 
apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on Israel Aircraft Industries Model 1124 airplanes modified by Avionics 
Certification Services. 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 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 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.

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

0
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 Israel Aircraft 
Industries Model 1124 airplanes modified by Avionics Certification 
Services.
    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 August 7, 2003.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-21106 Filed 8-15-03; 8:45 am]
BILLING CODE 4910-13-P