[Federal Register Volume 70, Number 13 (Friday, January 21, 2005)]
[Rules and Regulations]
[Pages 3140-3142]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-1156]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM300; Special Conditions No. 25-284-SC]


Special Conditions: Shadin Company, Inc., Cessna Aircraft Company 
Model 501 and 551 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 and 551 series airplanes modified by Shadin Company, 
Inc. 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 two Shadin Company Air Data Computers 
(ADC), Model ADC-6000. 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 January 12, 
2005. Comments must be received on or before February 22, 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. NM300, 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. NM300.

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 March 3, 2004, Shadin Company, Inc., 6831 Oxford Street, St. 
Louis Park, MN, 55426-4412, applied for a supplemental type certificate 
(STC) to modify Cessna Aircraft Company Model 501 and 551 series 
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; and the 
Cessna Model 551 is powered by two Pratt & Whitney Aircraft of Canada, 
Ltd., JT15D-4 turbofans. The Cessna Model 501 has a maximum takeoff 
weight of 11,850 pounds and the Cessna Model 551 has a maximum takeoff 
weight of 12,500 pounds. The Cessna Model 501 operates with one to two-
pilot crews and holds up to 9 passengers and the Cessna Model 551 
operates with one to two-pilot crews and holds up to 11 passengers. The 
modification incorporates the installation of two Shadin ADC 6000 
Reduced Vertical Separation Minimum (RVSM) capable systems, which will 
allow for the removal of the existing encoding altimeters, air data 
computer, and pneumatic altimeter. This system uses two ADC-6000s and 
interfaces to existing BA-141 altimeters. These ADCs can be susceptible 
to disruption to both command and response signals as a result of 
electrical and magnetic interference. This disruption of signals could 
result in the loss of all critical flight information displays and 
annunciations or the presentation of misleading information to the 
pilot. 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, Shadin Company, Inc. must 
show that the Cessna Aircraft Company Model 501 and 551 series 
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

[[Page 3141]]

the type certificate are commonly referred to as the ``original type 
certification basis.'' The certification basis for the Cessna Model 501 
series airplanes includes 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; and add Sec.  23.1385 as amended through 
amendment 23-20; and add 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.
    The certification basis for the Cessna Model 551 series airplanes 
includes part 23 of 14 CFR effective February 1, 1965, as amended by 
amendments 23-1 through 23-16 except as follows: Delete Sec. Sec.  
23.21 through 23.31, 23.45 through 23.77, 23.157, 23.171 through 
23.177, 23.251, 23.345, 23.351, 23.361, 23.471 through 23.511, 23.571, 
23.572, 23.629, 23.679, 23.723 through 23.737, 23.773, 23.775, 23.777, 
23.783, 23.807, 23.831, 23.903(c), 23.1091(c)(2), 23.1301, 23.1303, 
23.1307, 23.1309, 23.1321, 23.1323, 23.1325, 23.1385(c), 23.1435, 
23.1441 through 23.1449, 23.1581 through 23.1583(f), 23.1583(i) through 
23.1587; and add Sec. Sec.  23.1143(e) and 23.1385(c) as amended 
through amendment 23-18 and 23.1301 and 23.1335 as amended through 
amendment 23-20; and add from part 25 of 14 CFR effective February 1, 
1965, as amended by amendments 25-1 through 25-17, Sec. Sec.  25.812, 
25.863, 25.1195, 25.1199, 25.1203, 25.1309, and 25.1435; as amended by 
amendment 25-1 through 25-37, Sec. Sec.  25.21 through 25.31, 25.101 
through 25.125, 25.147(c)(e), 25.171 through 25.177, 25.251, 25.305(c), 
25.345, 25.351, 25.361, 25.471 through 25.511, 25.571, 25.573, 25.629, 
25.679, 25.721 through 25.737, 25.773, 25.775, 25.777, 25.783, 25.807, 
25.831, 25.851, 25.903(b)(d), 25.934, 25.1091(d)(2), 25.1189(g)(h), 
25.1197, 25.1201, 25.1303, 25.1305(a)(7), 25.1305(c)(4), 25.1307, 
25.1321, 25.1323, 25.1325, 25.1439 through 25.1453, 25.1581 through 
25.1583(c)(3), 25.1583(f) through 25.1587, and Sec. Sec.  25.901(c), 
25.903(e)(3), and 25.1351(d) as amended through amendment 25-41.
    In addition, the certification basis includes certain later amended 
sections of the applicable part 25 regulations that are not relevant to 
these special conditions.
    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 and 551 series 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 and 551 series 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 Shadin Company, Inc. 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 and 551 
series airplanes modified by Shadin Company, Inc. will incorporate a 
new altitude display system 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 and 551 series airplanes 
modified by Shadin Company, 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 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
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10 kHz-100 kHz..................................          50          50
100kHz-500 kHz..................................          50          50
500 kHz-2 MHz...................................          50          50
2 MHz-30 MHz....................................         100         100
30 MHz-70 MHz...................................          50          50
70 MHz-100MHz...................................          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-2GHz......................................        2000         200
2 GHz-4 GHz.....................................        3000         200
4 GHz-6 GHz.....................................        3000         200
6 GHz-8 GHz.....................................        1000         200

[[Page 3142]]

 
8 GHz-12 GHz....................................        3000         300
12 GHz-18 GHz...................................        2000         200
18 GHz-40 GHz...................................         600         200
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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 the 
Cessna Aircraft Company Model 501 and 551 series airplanes. Should 
Shadin Company, Inc. 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 and 551 series airplanes modified by Shadin 
Company, 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 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 and 551 series airplanes modified by Shadin Company, 
Inc.
    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 January 12, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-1156 Filed 1-19-05; 8:45 am]
BILLING CODE 4910-13-P