[Federal Register: August 2, 2007 (Volume 72, Number 148)]
[Rules and Regulations]
[Page 42274-42276]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02au07-2]
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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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