[Federal Register Volume 70, Number 238 (Tuesday, December 13, 2005)]
[Rules and Regulations]
[Pages 73559-73561]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-23935]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM336; Special Conditions No. 25-309-SC]


Special Conditions: Sabreliner Model NA-265-60 Airplanes; High-
Intensity Radiated Fields (HIRF).

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for Sabreliner Model NA-
265-60 airplanes modified by Flight Research, Inc. 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 altimeter/air data display units manufactured by 
Innovative Solutions and Support, Inc. These display units 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 5, 
2005. We must receive your comments by January 12, 2006.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attention: 
Rules Docket (ANM-113), Docket No. NM336, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. You may deliver two copies to the 
Transport Airplane Directorate at the above address. You must mark your 
comments: Docket No. NM336. You can 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 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, we invite 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 
concerning 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 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 6, 2005, Flight Research, Inc., 1062 Flight Line, Hangar 
161, Mojave, California 93501, applied for a Supplemental Type 
Certificate (STC) to modify Sabreliner Model NA-265-60 airplanes. These 
models are currently approved under Type Certificate No. A2WE. The 
Sabreliner Model NA-265-60 is a transport category airplane powered by 
two Pratt and Whitney Turbo Wasp JT12A-8 engines. The maximum takeoff 
weight is 20,172 pounds. These airplanes operate with a 2-person crew 
and can seat up to 10 passengers. The modification incorporates the 
installation of altimeter/air data display units manufactured by 
Innovative Solutions and Support, Inc. 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, Flight Research, Inc. must 
show that the Sabreliner Model NA-265-60, as changed, continues to meet 
the applicable provisions of the regulations incorporated by reference 
in Type Certificate No. A2WE, 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 certification basis for the 
Sabreliner Model NA-265-60 airplanes includes Civil Aeronautics Manual 
4b, as amended by Amendment 4b-1 through Amendment 4b-9, Special Civil 
Air Regulation No. SR 422B Item 2, the Special Conditions set forth in 
Attachment ``A'' of FAA letter to NAA [North American Aviation] dated 
October 8, 1959, and FAA letter to NAA dated January 30, 1962.
    If the Administrator finds that the applicable airworthiness 
regulations

[[Page 73560]]

(i.e., part 25, as amended) do not contain adequate or appropriate 
safety standards for the Sabreliner Model NA-265-60 airplanes 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, the Sabreliner Model NA-265-60 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 under 
Sec.  11.38 and become part of the type certification basis under Sec.  
21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should Flight Research, Inc. apply at a later date for 
a supplemental type certificate to modify any other model included on 
Type Certificate No. A2WE 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 Sabreliner Model NA-265-60 airplanes modified 
by Flight Research, Inc. will incorporate altimeter/air data display 
units that will perform critical functions. These display units 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, these systems are 
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 Sabreliner Model NA-265-60 airplanes 
modified by Flight Research, Inc. 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
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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
100MHz-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.
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    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 
Sabreliner Model NA-265-60 airplanes modified by Flight Research, Inc. 
Should Flight Research, Inc. apply at a later date for a supplemental 
type certificate to modify any other model included on Type Certificate 
No. A2WE to incorporate the same or similar novel or unusual design 
feature, these special conditions would apply to that model as well 
under provisions of Sec.  21.101.

[[Page 73561]]

Conclusion

    This action affects only certain novel or unusual design features 
on Sabreliner Model NA-265-60 airplanes modified by Flight Research, 
Inc. 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 Sabreliner Model NA-
265-60 airplanes modified by Flight Research, Inc.
    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 5, 2005.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-23935 Filed 12-12-05; 8:45 am]
BILLING CODE 4910-13-P