[Federal Register Volume 62, Number 50 (Friday, March 14, 1997)]
[Proposed Rules]
[Pages 12119-12121]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-6528]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-138, Notice No. SC-97-1-NM]
Special Conditions: Jetstream Aircraft Limited Model 4101
Airplane; Continuous Power Reserve (CPR) System
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This notice proposes special conditions for the Jetstream
Aircraft Limited Model 4101 airplane. This airplane will have a novel
or unusual design feature associated with installation of the CPR
system. This notice contains the additional safety standards that the
Administrator considers necessary to establish a level of safety
equivalent to that established by the airworthiness standards of part
25 of the FAR.
DATES: Comments must be received on or before April 28, 1997.
ADDRESSES: Comments on this proposal may be mailed in duplicate to:
Federal Aviation Administration, Office of the Assistant Chief Counsel,
Attention: Rules Docket (ANM-7), Docket No. NM-138, 1601 Lind Avenue
SW, Renton, Washington 98055-4056; or delivered in duplicate to the
Office of the Assistant Chief Counsel at the above address. Comments
must be marked: Docket No. NM-138. Comments may be inspected in the
Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and
4:00 p.m.
FOR FURTHER INFORMATION CONTACT:
William Schroeder, FAA, Standardization Branch, ANM-113, Transport
Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue
SW, Renton, Washington 98055-4056; telephone 206-227-2148; fax 206-227-
1149.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of
these proposed special conditions by submitting such written data,
views, or arguments as they may desire. Communications should identify
the regulatory docket or notice number and be submitted in duplicate to
the address specified above. All communications received on or before
the closing date for comments will be considered by the Administrator
before futher rulemaking action on this proposal is taken. The
proposals contained in this notice may be changed in light of the
comments received. All comments received will be available, both before
and after the closing date for comments, in the Rules Docket for
examination by interested parties. A report summarizing each
substantive public contact with FAA personnel concerning this
rulemaking will be filed in the docket. Commenters wishing the FAA to
acknowledge receipt of their comments submitted in response to this
notice must include a self-addressed, stamped postcard on which the
following statement is made:
[[Page 12120]]
``Comments to Docket No. NM-138.'' The postcard will be date stamped
and returned to the commenter.
Background
On June 7, 1994, Jetstream Aircraft Limited applied for approval of
a design change (without a new airplane model designation) to Type
Certificate No. A41NM for the installation of a CPR system on the
Jetstream Model 4101 airplane. The Jetstream Model 4101 is a 30
passenger, 23,000 pounds maximum take-off weight, transport category
airplane with two Allied Signal TPE331-14GR/HR series turbopropeller
engines. The CPR system makes a CPR power rating available for the
final take-off climb and en route phases of flight after failure of one
engine.
The CPR power rating for this engine installation is equivalent to
the maximum continuous power rating established for the engine under
Part 33 of the Federal Aviation Regulations (FAR). Following engine
failure, the CPR system automatically increases the engine maximum
exhaust gas temperature (EGT) limit, which permits the operating
engine's maximum continuous power rating to be obtained at higher
ambient air temperatures. Increased engine hour and cycle maintenance
factors apply for CPR power rating operation. Since the CPR power
rating will only be available during engine-out conditions, the maximum
power normally available with all engines operating will be less than
the part 33 certified maximum continuous power rating at certain higher
ambient temperature ranges.
The CPR system is novel when compared to those systems envisaged
when the applicable regulations in part 25 were promulgated. Therefore,
the airworthiness regulations in part 25 do not contain adequate or
appropriate safety standards for airplanes with CPR systems installed.
Special conditions are therefore prescribed to supplement the
certification basis of record for the Jetstream Model 4101 airplane
with a CPR system installed.
Type Certification Basis
Under the provisions of Sec. 21.101, Jetstream Aircraft Limited
must show that the Jetstream Model 4101, as changed, continues to meet
the applicable provisions of the regulations incorporated by reference
in Type Certificate No. A41NM 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. A41NM are part 25 of the FAR dated
February 1, 1965, as amended by Amendments 25-1 through 25-66. The
regulations incorporated by reference also include certain special
conditions, exemptions, and later amended sections of Part 25 that are
not relevant to these proposed special conditions.
If the regulations incorporated by reference do not provide
adequate standards with respect to the change, the applicant must
comply with certain regulations in effect on the date of application
for the change. The FAA has determined that the areas of the Jetstream
Model 4101 that are affected by the installation of the CPR system must
also be shown to comply with all sections of part 25 as amended by
Amendments 25-1 through 25-81 in effect on the date of application.
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 Jetstream Model 4101 because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of Sec. 21.16. When appropriate, special
conditions are issued in accordance with Sec. 11.49 of the FAR after
public notice, as required by Secs. 11.28 and 11.29(b), and become part
of the type certification basis in accordance with Sec. 21.101(b)(2).
Special conditions are initially applicable to the model for which they
are issued. Should the type certificate for that model be amended later
to include any other model that incorporates or should any other model
already included on the same type certificate be modified to
incorporate the same novel or unusual design feature, the special
conditions would also apply to the other model under the provisions of
Sec. 21.101(a)(1).
In addition to the applicable airworthiness regulations and special
conditions, the Jetstream Model 4101 must comply with the fuel vent and
exhaust emission requirements of part 34 and the noise certification
requirements of part 36.
Novel or Unusual Design Features
The Jetstream Model 4101 will incorporate a CPR system that
provides an engine power rating (as defined on the airplane) that is
equivalent to the engine's part 33 certified maximum continuous power
rating. Since the CPR power rating will only be available during
engine-out conditions, the maximum power available with all engines
operating will normally be less than the part 33 certified maximum
continuous power rating at certain higher ambient temperatures. The CPR
system is integrated into the existing approved Automatic Power Reserve
(APR) system. On the Jetstream 4100 airplane, the APR system is
equivalent to an Automatic Takeoff Thrust Control System (ATTCS) as
defined in Appendix I of Part 25. The currently approved APR system
automatically makes additional thermodynamic power and torque available
on the operating engine after engine failure during takeoff and for
approach climb (go-around). For certain ambient temperature ranges, the
proposed CPR system automatically increases the engine's EGT limit and
torque available on the operating engine for final take-off climb and
en route flight phases after failure of one engine. The CPR-related
increased EGT limit, which is above the two-engines-operating EGT
maximum continuous power and take-off limits, enables the operating
engine to achieve the flat-rated maximum continuous power (torque)
level at higher outside air temperature (OAT). Engine operation in the
APR and CPR modes requires application of engine hour and cycle
maintenance factors as specified in engine Type C Certificate Data
Sheet E18NE.
As discussed above, these special conditions are applicable to the
Jetstream Model 4101. Should Jetstream Aircraft Limited apply at a
later date for a change to the type certificate to include another
model incorporating the same novel or unusual design feature, these
special conditions would apply to that model as well under the
provisions of Sec. 21.101(a)(1).
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 it affects only the applicant who applied to the FAA for approval
of these features on the airplane.
List of Subjects in 14 CFR Part 25
Air transportation, Aircraft, Aviation safety, Safety.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for the Jetstream Model 4101 airplane.
[[Page 12121]]
Installation of a Continuous Power Reserve (CPR) System
(a) General. With the CPR system functioning normally as designed,
all applicable requirements of part 25 must be met without requiring
any unusual action (other than arming the system prior to dispatch) by
the crew to set power or thrust.
(b) Performance and Reliability Requirements.
(1) A CPR failure or combination of failures.
(i) That prevents the automatic insertion of CPR thrust or power
must be shown to be an improbable event;
(ii) That prevents the automatic insertion of APR thrust or power
during the critical time interval defined in Appendix I of Part 25 must
be shown to be an improbable event; and
(iii) Shall not result in the significant loss or reduction in
thrust or power, or must be shown to be an extremely improbable event.
(2) All applicable performance requirements of part 25 must be met
with an engine failure occurring at the most critical time with the CPR
system functioning.
(c) Thrust Setting. The maximum continuous thrust or power setting
specified for use with all engines operating may not be less than any
of the following:
(1) Ninety (90) percent of the thrust or power set by the CPR
system for which AFM performance credit is approved;
(2) That required to permit normal operation of all safety-related
systems and equipment dependent upon engine thrust or power lever
position; or
(3) That shown to be free of hazardous engine response
characteristics when thrust or power is advanced from the initial all-
engines-operating thrust or power setting to the maximum approved
maximum continuous/CPR mode thrust or power setting.
(d) Powerplant Controls.
(1) In addition to the requirements of Sec. 25.1141, no single
failure or malfunction, or probable combination thereof, of the CPR,
including associated systems, may cause the failure of any powerplant
function necessary for safety.
(2) The CPR system must be designed to:
(i) In the event of a CPR system failure, permit manual decrease or
increase in thrust or power up to the highest maximum continuous thrust
or power approved for the airplane under existing conditions through
the use of the power lever. For airplanes equipped with limiters that
automatically prevent engine operating limits from being exceeded under
existing ambient conditions, other means may be used to increase the
thrust or power in the event of a CFR failure provided the means is
located on or forward of the power levers; is easily identified and
operated under all operating conditions by a single action of either
pilot with the hand that is normally used to actuate the power levels;
and meets the requirements of Sec. 25.777 (a),(b), and (c).
(ii) Provide a means for the flightcrew to deactivate the automatic
CPR function. This means must be designed to prevent inadvertent
deactivation.
(iii) Provide a means for the flightcrew to verify that the CFR
system is in a condition to operate.
(e) Powerplant Instruments. In addition to the requirements of
Sec. 25.1305, a means must be provided to indicate when the CPR is in
the armed or ready condition.
Issued in Renton, Washington, on March 6, 1997.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 97-6528 Filed 3-13-97; 8:45 am]
BILLING CODE 4910-13-M
