[Federal Register Volume 70, Number 37 (Friday, February 25, 2005)]
[Rules and Regulations]
[Pages 9210-9212]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-3614]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM302; Special Conditions No. 25-286-SC]


Special Conditions: Cessna Aircraft Company Model 501 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 Aircraft 
Company Model 501 airplanes modified by Garrett Aviation Services. 
These airplanes will have novel and unusual design features when 
compared to the state of technology envisioned in the airworthiness 
standards for transport category airplanes. The modification 
incorporates the installation of Electronic Flight Displays with Engine 
Indication and Flight Information Systems. 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 February 16, 
2005. Comments must be received on or before March 28, 2005.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM302, 1601 Lind 
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. Comments 
must be marked: Docket No. NM302.

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-
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 airplanes 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 in light of the comments received.
    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 August 11, 2004, Garrett Aviation Services, 1200 North Airport 
Drive,

[[Page 9211]]

Capital Airport, Springfield, IL 62707, applied for a supplemental type 
certificate (STC) to modify Cessna Aircraft Company Model 501 
airplanes. These models are currently approved under Type Certificate 
No. A27CE. These Cessna airplane models are small transport category 
airplanes. The Cessna Model 501 is powered by two Pratt & Whitney 
Aircraft of Canada, Ltd., JT15D-1A or JT15D-1B turbofans; has a maximum 
takeoff weight of 11,850 pounds, and operates with one to two-pilot 
crews and holds up to 9 passengers. The modification incorporates the 
installation of the IDS-3000 Integrated Display System with EIS-3000 
Engine Indication System and IFIS-5000 Integrated Flight Information 
System. The avionics/electronics and electrical systems installed in 
these airplanes have the potential to be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplanes.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Garrett Aviation Services 
must show that the Cessna Aircraft Company Model 501 airplanes, as 
changed, continue to meet the applicable provisions of the regulations 
incorporated by reference in Type Certificate No. A27CE, 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 Cessna Model 501 
series airplanes include part 23 of 14 CFR effective February 1, 1965, 
as amended by amendments 23-1 through 23-16 except as follows: delete 
Sec. Sec.  23.45 through 23.77, 23.831, 23.1091(c)(2), 23.1303, 
23.1323, 23.1441 through 23.1449, 23.1581 through 23.1583(f), and 
23.1583(h) through 23.1587. Add Sec. Sec.  23.1385 as amended through 
23-20, and part 25 of 14 CFR effective February 1, 1965, as amended by 
amendments 25-1 through 25-17; Sec. Sec.  25.1195, 25.1199 and 25.1203 
as amended by amendments 25-1 through 25-37; Sec. Sec.  25.101 through 
25.125, 25.831, 25.934, 25.1091(d)(2), 25.1197, 25.1201, 25.1303, 
25.1305(a)(7), 25.1323, 25.1439 through 25.1453, 25.1581 through 
25.1583(c)(3), and Sec. Sec.  25.1583(e) through 25.1587.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25, as amended) do not contain adequate or 
appropriate safety standards for modified Cessna Aircraft Company Model 
501 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 Cessna Model 501 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 Garrett Aviation Services apply at a later date 
for a supplemental type certificate to modify any other model included 
on Type Certificate No. A27CE to incorporate the same 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 Cessna Aircraft Company Model 501 airplanes 
modified by Garrett Aviation Services will incorporate electronic 
displays with Engine Indication and Flight Information systems 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 electronic and electrical 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 Cessna Model 501 airplanes modified by 
Garrett Aviation 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 digital 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 is shown with either HIRF protection 
special condition 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

[[Page 9212]]

Electromagnetic Effects Harmonization Working Group of the Aviation 
Rulemaking Advisory Committee.

Applicability

    As discussed above, these special conditions are applicable to the 
Cessna Aircraft Company Model 501 airplanes. Should Garrett Aviation 
Services apply at a later date for a supplemental type certificate to 
modify any other model included on Type Certificate No. A27CEU to 
incorporate the same or similar novel or unusual design feature, these 
special conditions would apply to that model as well under the 
provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on the Cessna Model 501 airplanes modified by Garrett Aviation 
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 the special conditions for these airplanes 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 Aircraft 
Company Model 501 airplanes modified by Garrett Aviation Services.
    1. Protection from Unwanted Effects of High-Intensity Radiated 
Fields (HIRF). Each electronic and electrical 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 February 16, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-3614 Filed 2-24-05; 8:45 am]
BILLING CODE 4910-13-P