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[Federal Register Volume 69, Number 244 (Tuesday, December 21, 2004)]
[Rules and Regulations]
[Pages 76389-76391]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-27824]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM294; Special Conditions No. 25-277-SC]

Special Conditions: Raytheon Aircraft Company Model MU-300 and 
MU-300-10 Airplanes and Model 400 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 Raytheon Aircraft 
Company Model MU-300 and MU-300-10 airplanes and Model 400 airplanes 
modified by Beechjet TECH. 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 installation of two Shadin 
ADC-6400 RVSM-capable air data computers that 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 6, 
2004. Comments must be received on or before January 20, 2005.

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. NM294 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. NM294.

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 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 July 19, 2004, Beechjet TECH, 4500 S. Garnett, Suite 
600, Tulsa, Oklahoma 74146 applied for a supplemental type 
certificate (STC) to modify Raytheon Aircraft Company Model MU-300 and 
MU-300-10 airplanes and Model 400 airplanes. Model MU-300 is currently 
approved under Type Certificate No. A14SW and Models MU-300-10 and 400 
are currently approved under Type Certificate No. A16SW. The Raytheon 
Aircraft Company Model MU-300 and MU-300-10 airplanes and Model 400 
airplanes are small transport category airplanes powered by two 
turbojet

[[Page 76390]]

engines. They operate with a 2-pilot crew and can seat up to 9 
passengers. The modification incorporates the installation of two 
Shadin ADC-6400 air data computers, with the capability for operating 
the airplane at a reduced vertical separation minimum (RVSM). 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, Beechjet TECH must show that 
the Raytheon Aircraft Company Model MU-300 and MU-300-10 airplanes and 
Model 400 airplanes, as changed, continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificates No. A16SW or A14SW, as applicable, 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 bases for the Raytheon Aircraft Company Model MU-300 and 
MU-300-10 airplanes and Model 400 airplanes include 14 CFR part 25, as 
amended by Amendments 25-1 through 25-40; Sec. Sec.  25.1351(d), 
25.1353(c)(5), and 25.1450 as amended by Amendment 25-41; Sec. Sec.  
25.29, 25.255, and 25.1353(c)(6) as amended by Amendment 25-42; Sec.  
25.361(b) as amended by Amendment 25-46; and 14 CFR part 36 as amended 
by Amendment 36-1 through 36-12.
    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 Raytheon Aircraft Company Model 
MU-300 and MU-300-10 airplanes and Model 400 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 Raytheon Aircraft Company Model MU-300 and MU-300-10 
airplanes and Model 400 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 Beechjet TECH apply at a later date for a 
supplemental type certificate to modify any other model included on 
Type Certificate No. A16SW or A14SW, as applicable, to incorporate the 
same or similar novel or unusual design feature, these special 
conditions would also apply to the other model under the provisions of 
Sec.  21.101.

Novel or Unusual Design Features

    As noted earlier, the Raytheon Aircraft Company Model MU-300 and 
MU-300-10 airplanes and Model 400 airplanes modified by Beechjet TECH 
will incorporate two Shadin ADC-6400 RVSM-capable air data computers 
that will perform critical functions. These systems 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 Raytheon Aircraft Company Model MU-300 
and MU-300-10 airplanes and Model 400 airplanes modified by Beechjet 
TECH. 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
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 
Raytheon Aircraft Company Model MU-300 and MU-300-10 airplanes and 
Model 400 airplanes modified by Beechjet TECH. Should Beechjet TECH 
apply at a later date for a supplemental type certificate to modify any 
other model included on Type Certificate No. A16SW or A14SW, as 
applicable, to incorporate the same or similar novel or unusual design 
feature, these special conditions would apply to

[[Page 76391]]

that model as well under the provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on Raytheon Aircraft Company Model MU-300 and MU-300-10 airplanes and 
Model 400 airplanes modified by Beechjet TECH. 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 Raytheon Aircraft 
Company Model MU-300 and MU-300-10 airplanes and Model 400 airplanes 
modified by Beechjet TECH.
    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 6, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-27824 Filed 12-20-04; 8:45 am]
BILLING CODE 4910-13-P
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