[Federal Register Volume 72, Number 144 (Friday, July 27, 2007)]
[Rules and Regulations]
[Pages 41216-41218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-14593]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM380; Special Conditions No. 25-361-SC]


Special Conditions: Cessna Model 650 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 Cessna Model 650 
airplanes modified by Columbia Avionics, 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 consists of installing an 
Electronic Flight Instrument System (EFIS) with the options for the 
Universal Avionics Vision 1 Synthetic Vision System. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for the protection of these systems from the effects of high-

[[Page 41217]]

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 July 18, 2007. 
We must receive your comments by August 27, 2007.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attention: 
Rules Docket (ANM-113), Docket No. NM380, 1601 Lind Avenue SW., Renton, 
Washington 98057-3356. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM380. 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 98057-3356; 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 
about 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 by 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 March 15, 2007, Columbia Avionics, Inc., 11200 Airport Road, 
Columbia, Missouri, 65201, applied for a supplemental type certificate 
(STC) to modify Cessna Model 650 airplanes. The Cessna Model 650 is a 
low-wing, pressurized, transport category airplane with two fuselage-
mounted jet engines. It can seat up to 19 passengers, with a crew of 
two pilots. The modification consists of installing an electronic 
flight instrument system (EFIS) with the options for the Universal 
Avionics Vision 1 Synthetic Vision System. These systems have the 
potential to be vulnerable to high-intensity radiated fields (HIRF) 
external to the airplane.

Type Certification Basis

    Under 14 CFR 21.101, Columbia Avionics, Inc., must show that the 
Cessna Model 650 airplanes, as changed, continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A9NM, 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 incorporated by 
reference in Type Certificate No. A9NM include the following: Part 25 
of the Federal Aviation Regulations (FAR) effective February 1, 1965, 
as amended by Amendments 25-1 through 25-39. In addition, the following 
regulations apply: Sec. Sec.  25.901(c) and 25.1199, as amended by 
Amendments 25-1 through 25-40; Sec. Sec.  25.1309 and 25.1351(d), as 
amended by Amendments 25-1 through 25-41; Sec. Sec.  25.177, 25.255, 
and 25.703, as amended by Amendments 25-1 through 25-42; Sec.  25.1326, 
as amended by Amendments 25-1 through 25-43; Sec.  25.1413, as amended 
by Amendments 25-1 through 25-44; and Sec. Sec.  25.1305 and 25.1529, 
as amended by Amendments 25-1 through 25-54. In addition, the 
certification basis includes certain special conditions, exemptions, 
equivalent levels of safety, or later amended sections of the 
applicable part 25 regulations that are not relevant to these special 
conditions. These special conditions will form an additional part of 
the supplemental type certification basis.
    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 Cessna Model 650 airplanes because 
of a novel or unusual design feature, special conditions are prescribed 
under Sec.  21.16.
    Besides the applicable airworthiness regulations and special 
conditions, the Cessna Model 650 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 Columbia Avionics apply later for a 
supplemental type certificate to modify any other model included on 
Type Certificate No. A9NM 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 Cessna Model 650 airplanes modified Columbia 
Avionics will incorporate dual Electronic Primary Flight Displays 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

[[Page 41218]]

the regulations incorporated by reference, special conditions are 
needed for the Cessna 650 airplanes modified by Columbia Avionics. 
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 
Cessna Model 650 airplanes modified by Columbia Avionics. Should 
Columbia Avionics apply later for a supplemental type certificate to 
modify any other model included on Type Certificate No. A9NM to 
incorporate the same or similar novel or unusual design feature, these 
special conditions would apply to that model as well under Sec.  
21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on Cessna Model 650 airplanes modified by Columbia Avionics. 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 Cessna Model 650 
airplanes modified by Columbia Avionics.
    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 July 18, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-14593 Filed 7-26-07; 8:45 am]
BILLING CODE 4910-13-P