[Federal Register Volume 60, Number 38 (Monday, February 27, 1995)]
[Rules and Regulations]
[Pages 10483-10486]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4774]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 25
[Docket No. NM-103; Special Conditions No. 25-ANM-94]
Special Conditions: Dassault Aviation Model Falcon 2000 Airplane;
Automatic Takeoff Thrust Control System
agency: Federal Aviation Administration, DOT.
action: Final special conditions.
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summary: These special conditions are issued for the Dassault Aviation
Model Falcon 2000 airplane. This new airplane will have an unusual
design feature associated with an Automatic Takeoff Thrust Control
System (ATTCS), for which the applicable airworthiness regulations do
not contain appropriate safety standards for approach climb
[[Page 10484]] performance using an ATTCS. 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.
effective date: February 3, 1995.
for further information contact: Stephen Slotte, FAA, Standardization
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056, telephone
(206) 227-2797.
SUPPLEMENTARY INFORMATION:
Background
On September 13, 1989, Dassault Aviation, B.P. 24, 33701 Merignac
Cedex, France, applied for a new type certificate in the transport
airplane category for the Model Falcon 2000 airplane. The Dassault
Aviation Model Falcon 2000 is a medium-sized transcontinental business
jet powered by two General Electric/Garrett CFE 738 turbofan engines
mounted on pylons extending from the aft fuselage. Each engine will be
capable of delivering 5,600 lbs. thrust. The airplane will be capable
of operation with two flight crewmembers and eight passengers.
The Model Falcon 2000 will incorporate an unusual design feature,
the Automatic Takeoff Thrust Control System (ATTCS), referred to by
Dassault as Automatic Power Reserve or APR, to show compliance with the
approach climb requirements of Sec. 25.121(d). Appendix I to part 25
limits the application of performance credit for ATTCS to takeoff only.
Since the airworthiness regulations do not contain appropriate safety
standards for approach climb performance using ATTCS, special
conditions are required to ensure a level of safety equivalent to that
established in the regulations.
Type Certification Basis
Under the provisions of Sec. 21.17 of the FAR, Dassault Aviation
must show that the Falcon 2000 meets the applicable provisions or part
25, effective February 1, 1965, as amended by Amendments 25-1 through
25-69. The certification basis may also include later amendments to
part 25 that are not relevant to these special conditions. In addition,
the certification basis for the Falcon 2000 includes part 34, effective
September 10, 1990, plus any amendments in effect at the time of
certification; and part 36, effective December 1, 1969, as amended by
Amendments 36-1 through the amendment in effect at the time of
certification. These special conditions form an additional part of the
type certification basis. In addition, the certification basis may
include other special conditions 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 the Dassault Aviation Model Falcon
2000 because of a novel or unusual design feature, special conditions
are prescribed under the provisions of Sec. 21.16 to establish a level
of safety equivalent to that established in the regulations.
Special conditions, as appropriate, are issued in accordance with
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28
and 11.29, and become part of the type certification basis in
accordance with Sec. 21.17(a)(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 the same novel or
unusual design feature, 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).
Novel or Unusual Design Features
The Model Falcon 2000 will incorporate an unusual design feature,
the ATTCS (referred to by Dassault as the Automatic Power Reserve or
APR), to show compliance with the approach climb requirements of
Sec. 25.121(d). The FALCON 2000 is a twin-turbofan-powered airplane
equipped with Full Authority Digital Engine Controls (FADECs) that, in
part, protect against exceeding engine limits. Further, the FALCON 2000
incorporates a non-moving throttle system that functions by placing the
throttle levers in detents for the takeoff and climb phases of flight,
allowing the FADEC to schedule power setting based on flight phase.
With the throttle levers placed in either of the two forward detents
(takeoff/go-around and climb), if an engine failure (RPM (N1))
difference of greater than 10 percent between engines is sensed, power
is automatically advanced on the remaining engine to the APR power
level associated with the detent. The system is permanently armed and
will function any time the throttle levers are in either of the two
forward detents and an engine failure is sensed. Additionally, as in
the case of an APR failure, or in an all-engines mode, the crew can
select APR by placing the throttle levers in either of the two forward
detents and manually activating the system using an instrument panel-
mounted override switch.
APR power levels manifest themselves as an increase in the engine
flat-rating temperature for the operating altitude, and, in general,
result in higher thrust levels than those associated with the throttle
detents alone. Dassault also makes reference in the APR logic
description to thrust increase being armed for a throttle lever angle
above 27 degrees (max cruise position), but does not make it clear in
the system description if the APR system functions when the throttle is
not in a detent. Further discussions with Dassault make it clear that
when the throttle is between two detents, the FADEC makes a linear
interpolation between the related tables of corrected N1; i.e., an
almost linear thrust change. As function outside of a detent is
possible, then a throttle angle of 28 degrees (arming angle + 1 degree)
would produce almost no additional thrust when APR is activated, while
1 degree before the next detent (max cruise/max continuous) would
produce almost the same thrust increase as when the throttle is in that
detent. Logic for the max climb/max continuous detents is the same.
From a practical point of view, throttle positions between the detents
are not used.
The part 25 standards for ATTCS, contained in Sec. 25.904 and
Appendix I, specifically restrict performance credit for ATTCS to
takeoff. Expanding the scope of the standards to include other phases
of flight, including go-around, was considered at the time the
standards were issued, but flightcrew workload issues precluded further
consideration. As stated in the preamble to Amendment 25-62:
``In regard to ATTCS credit for approach climb and go-around
maneuvers, current regulations preclude a higher thrust for the
approach climb (Sec. 25.122(d)) than for the landing climb
(Sec. 25.119). The workload required for the flightcrew to monitor
and select from multiple in-flight thrust settings in the event of
an engine failure during a critical point in the approach, landing,
or go-around operations is excessive. Therefore, the FAA does not
agree that the scope of the amendment should be changed to include
the use of ATTCS for anything except the takeoff phase.'' (52 FR
43153, November 9, 1987)
The ATTCS incorporated on the FALCON 2000 allows the pilot to use
the same power setting procedure during a go-around, regardless of
whether or not an engine fails. In either case, the pilot obtains go-
around power by moving the throttles into the forward (takeoff/go-
around) throttle detent. [[Page 10485]] Since the ATTCS is permanently
armed, it will function automatically following an engine failure, and
advance the remaining engine to the ATTCS thrust level. Therefore, this
design adequately addresses the pilot workload concerns identified in
the preamble to Amendment 25-62. Accordingly, these special conditions
require a showing of compliance with those provisions of Sec. 25.904
and Appendix I that are applicable to the approach climb and go-around
maneuvers.
The definition of a critical time interval for the approach climb
case, during which time it must be extremely improbable to violate a
flight path based on the Sec. 25.121(d) gradient requirement, is of
primary importance. The Sec. 25.121(d) gradient requirement implies a
minimum one-engine-inoperative flight path capability with the airplane
in the approach configuration. The engine may have been inoperative
before initiating the go-around, or it may become inoperative during
the go-around. The definition of the critical time interval must
consider both possibilities.
Discussion of Comments
Notice of Proposed Special Conditions No. SC-94-4-NM for the
Dassault Aviation Model Falcon 2000 airplane was published in the
Federal Register on December 16, 1994 (59 FR 64869). No comments were
received, and the special conditions are adopted as proposed.
As discussed above, these special conditions are applicable to the
Dassault Aviation Model Falcon 2000. Should Dassault Aviation 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).
Under standard practice, the effective date of final special
conditions would be 30 days after the date of publication in the
Federal Register; however, as the certification date for the Falcon
2000 is imminent, the FAA finds that good cause exists to make these
special conditions effective upon issuance.
Conclusion
This action affects only certain design features on the Dassault
Aviation Model Falcon 2000 airplane. It is not a rule of general
applicability and affects only the manufacturer who applied to the FAA
for approval of these features on the airplane.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355,
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et
seq.; E.O. 11514; and 49 U.S.C. 106(g).
The Special Conditions
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 Dassault Aviation Model
Falcon 2000 airplane.
(a) General: An ATTCS is defined as the entire automatic system,
including all devices, both mechanical and electrical, that sense
engine failure, transmit signals, actuate fuel controls or power
levers, or increase engine power by other means on operating engines
to achieve scheduled thrust or power increases and furnish cockpit
information on system operation.
(b) Automatic takeoff thrust control system (ATTCS). The engine
power control system that automatically resets the power or thrust
on the operating engine (following engine failure during the
approach for landing) must comply with the following requirements:
(1) Performance and System Reliability Requirements. The
probability analysis must include consideration of ATTCS failure
occurring after the time at which the flightcrew last verifies that
the ATTCS is in a condition to operate until the beginning of the
critical time interval.
(2) Thrust Setting. The initial takeoff thrust set on each
engine at the beginning of the takeoff roll or go-around may not be
less than:
(i) Ninety (90) percent of the thrust level set by the ATTCS
(the maximum takeoff thrust or power approved for the airplane under
existing ambient conditions);
(ii) That required to permit normal operation of all safety-
related systems and equipment dependent upon engine thrust or power
lever position; or
(iii) That shown to be free of hazardous engine response
characteristics when thrust is advanced from the initial takeoff
thrust or power to the maximum approved takeoff thrust or power.
(3) Powerplant Controls. In addition to the requirements of
Sec. 25.1141, no single failure or malfunction, or probable
combination thereof, of the ATTCS, including associated systems, may
cause the failure of any powerplant function necessary for safety.
The ATTCS must be designed to:
(i) Apply thrust or power on the operating engine(s), following
any one engine failure during takeoff or go-around, to achieve the
maximum approved takeoff thrust or power without exceeding engine
operating limits; and
(ii) Provide a means to verify to the flightcrew before takeoff
and before beginning an approach for landing that the ATTCS is in a
condition to operate.
(c) Critical Time Interval. The definition of the Critical Time
Interval in Appendix I, Section I25.2(b) shall be expanded to
include the following:
(1) When conducting an approach for landing using ATTCS, the
critical time interval is defined as follows:
(i) The critical time interval begins at a point on a 2.5 degree
approach glide path from which, assuming a simultaneous engine and
ATTCS failure, the resulting approach climb flight path intersects a
flight path originating at a later point on the same approach path
corresponding to the Part 25 one-engine-inoperative approach climb
gradient. The period of time from the point of simultaneous engine
and ATTCS failure to the intersection of these flight paths must be
no shorter than the time interval used in evaluating the critical
time interval for takeoff beginning from the point of simultaneous
engine and ATTCS failure and ending upon reaching a height of 400
feet.
(ii) The critical time interval ends at the point on a minimum
performance, all-engines-operating go-around flight path from which,
assuming a simultaneous engine and ATTCS failure, the resulting
minimum approach climb flight path intersects a flight path
corresponding to the Part 25 minimum one-engine-inoperative approach
climb gradient. The all-engines-operating go-around flight path and
the Part 25 one-engine-inoperative approach climb gradient flight
path originate from a common point on a 2.5 degree approach path.
The period of time from the point of simultaneous engine and ATTCS
failure to the intersection of these flight paths must be no shorter
than the time interval used in evaluating the critical time interval
for the takeoff beginning from the point of simultaneous engine and
ATTCS failure and ending upon reaching a height of 400 feet.
(2) The critical time interval must be determined at the
altitude resulting in the longest critical time interval for which
one-engine-inoperative approach climb performance data are presented
in the Airplane Flight Manual.
(3) The critical time interval is illustrated in the following
figure:
BILLING CODE 4910-13-M
[[Page 10486]]
[GRAPHIC][TIFF OMITTED]TR27FE95.009
BILLING CODE 4910-13-C
Issued in Renton, Washington, on February 3, 1995.
Darrell M. Pederson,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service, NAM-101.
[FR Doc. 95-4774 Filed 2-24-95; 8:45 am]
BILLING CODE 4910-13-M
