[Federal Register Volume 65, Number 214 (Friday, November 3, 2000)]
[Rules and Regulations]
[Pages 66165-66168]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-28294]



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Rules and Regulations
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Federal Register / Vol. 65, No. 214 / Friday, November 3, 2000 / 
Rules and Regulations

[[Page 66165]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR part 25

[Docket No. NM178; Special Conditions No. 25-167-SC]


Special Conditions: Bombardier Model CL-600-2C10 Airplane; 
Automatic Takeoff Thrust Control System

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 Bombardier Model 
CL-600-2C10 series airplanes. This new airplane will have a novel or 
unusual design feature associated with an Automatic Takeoff Thrust 
Control System (ATTCS). The applicable airworthiness regulations do not 
contain appropriate safety standards for approach climb performance 
using an ATTCS. These special conditions contain the additional safety 
standards 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 October 24, 
2000.
    Send your comments on or before December 18, 2000.

ADDRESSES: Mail your comments on these special conditions in duplicate 
to: Federal Aviation Administration, Transport Airplane Directorate, 
Attention: Rules Docket (ANM-114), Docket No. NM178, 1601 Lind Avenue 
SW., Renton, Washington 98055-4056; or deliver them to the Transport 
Airplane Directorate at that address. You must mark your comments: 
Docket No. NM178. You may inspect all comments at that address on 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Gerry Lakin, FAA, Transport Airplane 
Directorate, Aircraft Certification Office, Standardization Branch, 
ANM-113, 1601 Lind Avenue SW., Renton, Washington, telephone (425) 227-
1187; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
those 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

    Interested persons are invited to submit 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 by the closing 
date for comments will be considered by the Administrator. These 
special conditions may be changed in light of the comments received. 
All comments received will be available in the Rules Docket for 
examination by interested persons, both before and after the closing 
date for comments. 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: 
``Comments to Docket No. NM178.'' The postcard will be date stamped and 
returned to the commenter.

Background

    On May 6, 1996, Bombardier Aerospace applied for an amendment to 
U.S. Type Certificate (TC) A21EA, through Transport Canada, to include 
the Bombardier Model CL600-2C10 series airplane (Regional Jet Series 
700). The Model CL600-2C10 is a medium-sized transport category 
airplane powered by two General Electric Aircraft Engines (GEAE) CF34-
8C1 turbofan engines mounted on the aft fuselage. Each engine can 
deliver up to 13,790 pounds of thrust at takeoff. The airplane will be 
capable of operating with 5 flight crewmembers and up to 78 passengers.
    The Model CL600-2C10 will incorporate an unusual design feature to 
show compliance with the approach climb requirements of Sec. 25.121(d) 
(``Climb: One-engine-inoperative''). This design feature is the 
Automatic Takeoff Thrust Control System (ATTCS), referred to by 
Bombardier as Automatic Power Reserve (APR). Appendix I to Title 14, 
Code of Federal Regulations (CFR), 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 (``Designation of applicable 
regulations''), Bombardier must show that the Model CL600-2C10 meets 
the applicable provisions of:
    <bullet> 14 CFR part 25, effective February 1, 1965, including 
amendments 25-1 through 25-86; and
    <bullet> Sec. 25.109 (``Accelerate-stop distance''), as amended by 
amendment 25-92.
    The certification basis also may include later amendments to part 
25 that are not relevant to these special conditions. In addition, the 
certification basis for the Model CL600-2C10 includes:
    <bullet> 14 CFR part 34, effective September 10, 1990, including 
amendment 34-3, effective February 3, 1999, as well as any amendments 
in effect at the time of certification; and
    <bullet> 14 CFR part 36, effective December 1, 1969, including 
amendments 36-1 through 36-22, and any following amendments that will 
be applicable on the date the type certificate is issued.
    These special conditions form an additional part of the type 
certification basis. The certification basis also may include other 
special conditions that are not relevant to these specific special 
conditions.

[[Page 66166]]

    If the Administrator finds that the applicable airworthiness 
regulations (in this case, part 25) do not contain adequate or 
appropriate safety standards for the Bombardier Model CL600-2C10 
because of a novel or unusual design feature, the FAA may prescribe 
special conditions under the provisions of Sec. 21.16 (``Special 
conditions''). The special conditions become part of the type 
certification basis in accordance with Sec. 21.101(b)(2) (``Designation 
of applicable regulations'').
    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

    As stated previously, the Model CL600-2C10 will incorporate an 
unusual design feature, the ATTCS (referred to by Bombardier as APR), 
to show compliance with the approach climb requirements of 
Sec. 25.121(d). The Model CL600-2C10 is powered by two GEAE CF34-8C1 
turbofan engines mounted on the aft fuselage of the airplane, and 
equipped with Full Authority Digital Engine Controls (FADEC) that, in 
part, protect against exceeding engine limits. Further, the airplane 
incorporates a non-moving throttle system that functions by placing the 
throttle levers in detents for the takeoff and climb phases of flight; 
this allows the FADEC to schedule the power setting based on the phase 
of flight. With the APR and associated systems functioning normally as 
designed, all applicable requirements of part 25 will be met without 
requiring any action by the flight crew to increase power.
    Automatic takeoff power control on the Model CL600-2C10 involves 
uptrimming the operating engine to maximum takeoff power (APR). These 
actions will be controlled by the FADEC. At takeoff, when the power 
levers are set to the Takeoff Go-Around (TOGA) detent, if there are no 
FADEC fault or failure messages displayed, the system is armed and APR 
will occur without any further action by the crew if an engine fails. 
During go-around, the uptrim is automatically armed.
    Engine power is set to TOGA to initiate the takeoff roll. The value 
of TOGA for the current ambient conditions will be calculated and set 
by the FADEC. Following an engine failure during takeoff or go-around, 
the ATTCS will change the power reference on the operating engine to 
achieve the maximum takeoff power rating if the engine power was 
originally set to normal takeoff power. If the reduced power takeoff 
option is being used, the ATTCS will increase the power of the 
operating engine to the maximum takeoff rating, although the aircraft 
performance will be based on a 10% power increase only.
    The engine operating limits (turbine temperature and N<INF>1</INF>) 
for TOGA are set and displayed to the pilot when that rating is 
selected. These limits are set in such a way that the engine redline 
limits are not exceeded when an APR is engaged. When the maximum 
takeoff power rating is selected or triggered, the engine limits are 
reset automatically to reflect the engine redline limits.
    The system is armed during all phases of the flight. The power 
levers will continue to function normally if the ATTCS should fail. 
Full takeoff power is available if the pilot elects to push the power 
levers past the takeoff power detent into the overtravel range.
    Operations of all systems and equipment will be designed to 
function within the engine power range. Thrust increase from the 
initial to the maximum approved takeoff power level will be free of 
hazardous engine response characteristics.
    The APR function, as described above, is part of the powerplant 
control system. The APR is always armed whenever power levers are above 
the idle detent. The system is verified before each flight via the 
FADEC built-in test feature. When the APR is triggered following an 
engine failure, an ``APR'' message will appear on the engine display.
    The FADEC installed on the Model CL600-2C10 will ensure that 
inherent flight characteristics of the airplane do provide adequate 
warning if an engine failure occurs during takeoff. The natural yawing 
tendency of the airplane, coupled with flashing master warning and 
master caution lights, will provide the pilot with a clear indication 
of any engine failure during takeoff.
    The part 25 standards for ATTCS, contained in Sec. 25.904 
(Automatic takeoff thrust control system (ATTCS)'') and Appendix I, 
specifically restrict performance credit for ATTCS to takeoff only. 
Expanding the scope of the standards to include other phases of flight, 
such as go-around, was considered at the time the standards were 
issued, but flight crew 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. 25.121(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.'' (Refer to 
52 FR 43153, November 9, 1987.)

    The ATTCS incorporated on the Model CL600-2C10 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. 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 would 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 gradient requirement of Sec. 25.121(d), is of 
primary importance. That 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.

Applicability

    As discussed above, these special conditions would be applicable to 
the Bombardier Model CL600-2C10. Should Bombardier 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 the

[[Page 66167]]

Bombardier Model CL600-2C10 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 public comment process in several prior instances, and has 
been derived without substantive change from those special conditions 
previously issued. It is unlikely that prior public comment on this 
action would result in a significant change from the substance 
contained in this document. For this reason, and 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. 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.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

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 Bombardier Model CL600-2C10 
airplane.
    1. General. An Automatic Takeoff Thrust Control System (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.
    2. 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 stated in paragraphs 2.a, 2.b, and 2.c:
    a. 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.
    b. Thrust or Power Setting.
    (1) The initial thrust or power setting on each engine at the 
beginning of the takeoff roll or go-around may not be less than any of 
the following:
    (i) That required to permit normal operation of all safety-related 
systems and equipment dependent upon engine thrust or power lever 
position; or
    (ii) That shown to be free of hazardous engine response 
characteristics and not to result in any unsafe aircraft operating or 
handling characteristics when thrust or power is increased from the 
initial takeoff or go-around thrust or power to the maximum approved 
takeoff thrust or power.
    (2) For approval of an ATTCS system for go-around, the thrust or 
power setting procedure must be the same for go-arounds initiated with 
all engines operating as for go-arounds initiated with one engine 
inoperative.
    c. 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:
    (1) 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
    (2) 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.
    3. Critical Time Interval. The definition of the Critical Time 
Interval in appendix I, Sec. I25.2(b) shall be expanded to include the 
following:
    a. When conducting an approach for landing using ATTCS, the 
critical time interval is defined as follows:
    (1) 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.
    (2) 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.
    b. 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 (AFM).
    c. The critical time interval is illustrated in the following 
figure:

[[Page 66168]]

[GRAPHIC] [TIFF OMITTED] TR03NO00.027


    Issued in Renton, Washington, on October 24, 2000.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-28294 Filed 11-2-00; 8:45 am]
BILLING CODE 4910-13-P