[Federal Register Volume 72, Number 148 (Thursday, August 2, 2007)]
[Rules and Regulations]
[Pages 42274-42276]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-14933]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE261; Special Conditions No. 23-201-SC]


Special Conditions: Centex Aerospace, Inc.; Cirrus Design 
Corporation Model SR22; Installation of a Full Authority Digital Engine 
Control (FADEC) Engine

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Cirrus Design 
Corporation, Model SR22 airplane as modified by Centex Aerospace, Inc. 
This airplane as modified by Centex Aerospace, Inc. will have a novel 
or unusual design feature(s) associated with the installation of a full 
authority digital engine control (FADEC) engine. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. 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 26, 2007.
    Comments must be received on or before September 4, 2007.

ADDRESSES: Mail two copies of your comments to: Federal Aviation 
Administration, Regional Counsel, ACE-7, Attn: Rules Docket No. CE261, 
901 Locust, Kansas City, MO 64106. You may deliver two copies to the 
Regional Counsel at the above address. Mark your comments: Docket No. 
CE261. You may inspect comments in the Rules Docket weekdays, except 
Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Peter L. Rouse, Federal Aviation 
Administration, Small Airplane Directorate, Aircraft Certification 
Service, 901 Locust, Room 301, Kansas City, MO 64106; telephone (816) 
329-4135; facsimile (816) 329-4090.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay issuance of the approval 
design 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.

Comments Invited

    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 can 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 us to let you know we received your comments on these 
special conditions, send us 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, 2004, Centex Aerospace, Inc. applied for a 
supplemental type certificate for the Cirrus Model SR22 to install a 
full authority digital engine control in the Cirrus Model SR22. CenTex 
Aerospace, Inc. plans to install a Teledyne Continental Motors model 
IOF-550-N engine in a Cirrus Design Corporation Model SR-22 airplane. 
This type certified engine, approved under FAA Type Certificate E3SO; 
Revision 7, dated February 4, 2002, incorporates Full Authority Digital 
Electronic Controls (FADEC) fuel and ignition control system. Even 
though the engine control system is certificated as part of the engine 
and does not interface or share data with any of the airplane systems, 
the installation of an engine with an electronic control system 
requires evaluation due to critical environmental effects and possible 
effects on or by other airplane systems. For example,

[[Page 42275]]

indirect effects of lightning, radio interference with other airplane 
electronic systems, shared engine and airplane data and power sources.
    The Cirrus SR 22 is currently approved under Type Certificate No. 
A00009CH. The Cirrus SR-22 is a 3,400 pound single-engine, four-place, 
fixed-gear airplane powered by a 310 hp reciprocating engine. It has a 
conventional tractor configuration and utilizes composites for the 
structure. Some unique features of the SR-22 include sidestick controls 
and a ballistic recovery system, and a single combination throttle/
propeller control lever.
    The considerations for installation of digital electronic engine 
control systems were not envisaged and are not adequately addressed in 
14 CFR part 23. The regulatory requirements in 14 CFR part 23 for 
evaluating the installation of complex systems, including electronic 
systems and critical environmental effects, are contained in Sec.  
23.1309. However, when Sec.  23.1309 was developed, the use of highly 
airframe integrated electronic control systems for engines was not 
envisioned. Therefore, the Sec.  23.1309 requirements were not 
applicable to systems certificated as part of the engine (reference 
Sec.  23.1309(f)(1)). The parts of the system that are not certificated 
with the engine could be evaluated using the criteria of Sec.  23.1309. 
However, the integral nature of systems such as these makes it 
unfeasible to evaluate the airplane portion of the system without 
including the engine portion of the system. Section 23.1309(f)(1) 
prevents complete evaluation of the installed airplane system since 
evaluation of the engine system's effects is not required.

Type Certification Basis

    Under the provisions of Sec.  21.101, Centex Aerospace, Inc. must 
show that the Cirrus Design Corporation Model SR22, as changed, 
continues to meet the applicable provisions of the regulations 
incorporated by reference in Type Certificate No. A00009CH, 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. A00009CH are as follows:
    Model SR22: Part 23 of the Federal Aviation Regulations effective 
February 1, 1965, as amended by 23-1 through 23-53, except as follows:

23.301 through Amendment 47
23.855, 23.1326, 23.1359, not applicable
Federal Aviation Regulations 36 dated December 1, 1969, as amended by 
current amendment as of the date of type Certification.

    Equivalent Safety Items:

Equivalent Levels of Safety finding (ACE-96-5) made per the provisions 
of 14 CFR part 23, Sec.  23.221; Refer to FAA ELOS letter dated June 
10, 1998 for models SR20, SR22.
Equivalent Levels of Safety finding (ACE-00-09) made per the provisions 
of 14 CFR part 23, Sec. Sec.  23.1143(g) and 23.1147(b); Refer to FAA 
ELOS letter dated September 11, 2000, for model SR22.

    Special Conditions:

23-ACE-88 for ballistic parachute
23-134-SC for protection of systems for High Intensity Radiated Fields 
(HIRF)
23-163-SC for inflatable restraint system

    In addition, if the regulations incorporated by reference do not 
provide adequate standards regarding the change, the applicant must 
comply with certain regulations in effect on the date of application 
for the change.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 23, Sec.  23.1309) do not contain 
adequate or appropriate safety standards for the Model SR22 because of 
a novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38 and they 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 the applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
the special conditions would also apply to the other model.

Novel or Unusual Design Features

    The Centex Aerospace, Inc. modified Cirrus Model SR22 will 
incorporate the following novel or unusual design features:
    An engine that includes an electronic control system with Full 
Authority Digital Engine control (FADEC) capability.

Discussion

    The regulatory requirements in 14 CFR part 23 for evaluating the 
installation of complex systems, including electronic systems and 
critical environmental effects, are contained in Sec.  23.1309. 
However, when Sec.  23.1309 was developed, the use of electronic 
control systems for engines were not envisioned. Therefore, the Sec.  
23.1309 requirements were not applicable to systems certificated as 
part of the engine (reference Sec.  23.1309(f)(1)). Although the parts 
of the system that are not certificated with the engine could be 
evaluated using the criteria of Sec.  23.1309, the integral nature of 
systems such as these makes it unfeasible to evaluate the airplane 
portion of the system without including the engine portion of the 
system. However, Sec.  23.1309(f)(1) again prevents complete evaluation 
of the installed airplane system since evaluation of the engine 
system's effects is not required.
    The Policy Statement; Installation of Electronic Engine Control for 
Reciprocating Engine, PS-ACE100-2004-10024, states:

    The current Small Airplane Directorate Standards Office policy 
on EEC installation in small airplanes, under Sec.  23.1309, has 
been to issue two special conditions. The first special condition 
applies Sec.  23.1309(a) through (e) to the propulsion system 
installation. The second special condition is protection of the EEC 
from exposure to HIRF. The evaluation should be limited to the 
interfaces of the engine/control system and verification that none 
of the assumptions made for part 33 certification of the engine are 
invalidated by the installation. The analysis should not extend into 
data submitted and approved as part of the engine certification 
program.

    The Lightning and HIRF certification requirements for design and 
installation approval of electronic equipment are presented in 14 CFR 
part 23, Sec.  23.1309, and Advisory Circular (AC) 23.1309-1C and AC 
23-17A. However, a typical misinterpretation is that the concepts in AC 
23.1309-1C can be applied to engine control systems to reduce the 
certification requirements for single engine airplanes.
    The EEC is certified as part of the engine design certification, 
the certification requirements for engine control systems must be 
driven by 14 CFR part 33 and the two advisory circulars; AC 33.28-1 and 
AC 33.28-2. Both of those Advisory Circulars clearly state that 
electronic engine controls must provide the same level of safety as 
traditional mechanical engine controls. We believe the EEC systems have 
additional failure modes that were not present in purely mechanical 
engine controls. To ensure an equivalent level of safety, the FAA 
position has always been:

    EEC System with catastrophic and hazardous failure conditions, 
without an acceptable conventional engine control backup, lightning 
and HIRF protection levels are required to be certified to the 
levels for catastrophic failure conditions.

[[Page 42276]]

    The environmental certification tests are normally conducted 
with the appropriate category and level of RTCA/DO-160. For HIRF, it 
is at the environment in the notice or category W of section 20 of 
RTCA/DO-160. For indirect effects of lightning, it is at the 
appropriate category and level for pin injection tests and multiple 
stroke and multiple burst tests of section 22 of RTCA/DO-160. When 
appropriate, engine certification data may be used when showing 
compliance with this requirement. However, the effects of the 
installation on this data must be addressed.

    The applicant will comply with the following special condition:

    The installation of the electronic engine control system must 
comply with the requirements of Sec.  23.1309(a) through (e) at 
Amendment 23-49. The intent of this requirement is not to reevaluate 
the inherent hardware reliability of the control itself, but rather 
determine the effects, including environmental effects addressed in 
Sec.  23.1309(e), on the airplane systems and engine control system 
when installing the control on the airplane. When appropriate, 
engine certification data may be used when showing compliance with 
this requirement; however, the effects of the installation on this 
data must be addressed.

With respect to compliance with Sec.  23.1309(e), the levels required 
for compliance shall be at the levels for catastrophic failure 
conditions.

Applicability

    As discussed above, these special conditions are applicable to the 
Cirrus Model SR22 as modified by Centex Aerospace, Inc. Should Centex 
Aerospace, Inc. apply at a later date for a supplemental type 
certificate to modify any other model included on Type Certificate No. 
A00009CH, to incorporate the same novel or unusual design feature, the 
special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of airplane. 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 period in several prior instances and has been 
derived without substantive change from those previously issued. It is 
unlikely that prior public comment would result in a significant change 
from the substance contained herein. Therefore, 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 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

0
The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
21.101; and 14 CFR 11.38 and 11.19.

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 type certification basis for the Cirrus Model SR22 airplanes as 
modified by Centex Aerospace, Inc.
    1. Electronic Engine Control System
    The installation of the electronic engine control system must 
comply with the requirements of Sec.  23.1309(a) through (e) at 
Amendment 23-49. The intent of this requirement is not to reevaluate 
the inherent hardware reliability of the control itself, but rather 
determine the effects, including environmental effects addressed in 
Sec.  23.1309(e), on the airplane systems and engine control system 
when installing the control on the airplane. When appropriate, engine 
certification data may be used when showing compliance with this 
requirement; however, the effects of the installation on this data must 
be addressed.
    With respect to compliance with Sec.  23.1309(e), the levels 
required for compliance shall be at the levels for catastrophic failure 
conditions.

    Issued in Kansas City, Missouri on July 26, 2007.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-14933 Filed 8-1-07; 8:45 am]
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