Special Conditions: Gulfstream Aerospace LP (GALP) Model G250 Airplane Automatic Power Reserve (APR), an Automatic Takeoff Thrust Control System (ATTCS), 35736-35739 [2011-15175]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 76, Number 118 (Monday, June 20, 2011)]
[Rules and Regulations]
[Pages 35736-35739]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-15175]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM459; Special Conditions No. 25-432-SC]


Special Conditions: Gulfstream Aerospace LP (GALP) Model G250 
Airplane Automatic Power Reserve (APR), an Automatic Takeoff Thrust 
Control System (ATTCS)

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 Gulfstream 
Aerospace LP (GALP) Model G250 airplane. This airplane will have a 
novel or unusual design feature associated with go-around performance 
credit for use of Automatic Power Reserve (APR), an Automatic Takeoff 
Thrust Control System (ATTCS). 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 June 13, 2011. 
We must receive your comments by August 4, 2011.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM459, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM459. You can inspect comments in the Rules Docket 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Joe Jacobsen, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 227-2011; facsimile 
(425) 227-1149.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and 
opportunity for prior public comment on, these special conditions are 
impracticable because 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. 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 may change these special conditions based on the comments 
we receive.
    If you want us to acknowledge receipt of your comments on these 
special conditions, include with your comments a self-addressed, 
stamped postcard on which you have written the docket number. We will 
stamp the date on the postcard and mail it back to you.

Background

    On March 30, 2006, GALP applied for a type certificate for their 
new Model G250 airplane. The G250 is an 8-10

[[Page 35737]]

passenger (19 maximum), twin-engine airplane with a maximum operating 
altitude of 45,000 feet and a range of approximately 3,400 nautical 
miles. Airplane dimensions are 61.69-foot wing span, 66.6-foot overall 
length, and 20.8-foot tail height. Maximum takeoff weight is 39,600 
pounds and maximum landing weight 32,700 pounds. Maximum cruise speed 
is mach 0.85, dive speed is mach 0.92. The avionics suite will be the 
Rockwell Collins Pro Line Fusion.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, GALP must show that the Model 
G250 airplane meets the applicable provisions of part 25 as amended by 
Amendments 25-1 through 25-117.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Model G250 airplane because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of Sec.  21.16.
    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, the special conditions would also apply to the 
other model.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model G250 airplane must comply with the fuel-vent and 
exhaust-emission requirements of 14 CFR part 34 and the noise-
certification requirements of 14 CFR part 36; and the FAA must issue a 
finding of regulatory adequacy under Sec.  611 of Public Law 92-574, 
the ``Noise Control Act of 1972.''
    The FAA issues special conditions, as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Model G250 will incorporate the following novel or unusual 
design feature:
    GALP has requested approval to use an Automatic Takeoff Thrust 
Control System (ATTCS; referred to by GALP as Automatic Power Reserve 
(APR)) as the performance level in showing compliance with the approach 
climb requirements of 14 CFR 25.121(d). Section 25.904 and Appendix I 
to part 25 of 14 CFR limit 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.

Discussion

    GALP is proposing to use the APR function of the Model G250 
airplane during go-around and is requesting approach climb performance 
credit for the use of the additional power provided by the uptrim. The 
GALP powerplant control system comprises a Full Authority Digital 
Electronic Control (FADEC) for the Honeywell AS907-2-1G engine. The 
control system includes an ATTCS feature referred to as APR.
    The ATTCS (APR) function is integrated into the FADEC such that 
there is no separate circuitry for the APR function. Both FADECs are 
connected via a communications bus. Each FADEC sends information to the 
other. When the FADEC of any engine detects either the loss of 
communication or an indication of significant thrust loss from the 
opposite engine, the FADEC of the healthy (or both) engine will 
increase the power to the APR rating and the ``APR'' (activated) icon 
will appear on the EICAS inside the N1 gauge for the engine with its 
Throttle Lever Angle (TLA) set at takeoff (TO) power. In addition, APR 
is always available to the flightcrew for each engine, with its TLA set 
at TO power by pushing the ``APR manual'' pushbutton. If the TRA is not 
set to the TO power setting, this just arms both engines for APR. Once 
manually armed, whenever either TLA is advanced to the TO power 
setting, that engine increases power to APR rating regardless of the 
condition of the other engine.
    The APR feature is always armed unless the flight crew selects to 
disarm it for single-engine-operation training purposes. When this 
disarmed condition is active, an amber caution message is provided. The 
normal operating procedure will be to leave APR armed at all times. The 
APR function will be checked as part of the normal FADEC continuous 
self-test feature. The engine, by virtue of the integrated power 
schedule imbedded in the FADEC software, cannot continue running if 
uptrim fails. This function is retained even in the case of a FADEC 
single-channel failure.
    The above description highlights the fact that the APR power is 
available at all times for any TO operational segment without any 
additional action from the pilot. This applies during takeoff and go-
around (TOGA). The aircraft performance data is based on the 
availability of the uptrim power during takeoff and approach climb.
    The ATTCS, as incorporated on the Model G250 airplane, allows the 
pilot to use the ``Auto APR'' procedure for the one-engine-inoperative 
(OEI) case and the ``Manual APR'' procedure while both engines are 
operative; in either case, the pilot obtains the additional go-around 
power by moving the power levers to the TO power setting. Full APR 
thrust is provided up to 20,000 ft. MSL.
    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 the preamble of amendment 62 to part 25 states:

    ``In regard to ATTCS credit for approach climb and go-around 
maneuvers, current regulations preclude a higher power 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 power 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.''

    The ATTCS incorporated on the Model G250 airplane 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 power levers to the TOGA detent. Since 
the ATTCS is always armed, it will function automatically following an 
engine failure, and advance the remaining engine to the APR power 
level.
    Because the airworthiness regulations do not contain appropriate 
safety standards to allow approach climb performance credit for ATTCS, 
special conditions are required to ensure a level of safety equivalent 
to that established in the regulations. 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. In the event 
of a simultaneous failure of an engine and the APR function, falling 
below the minimum flight path defined by the 2.5-degree approach, 
decision height, and climb gradient required by Sec.  25.121(d) must be 
shown to be an extremely improbable event during this critical time 
interval. The Sec.  25.121(d) gradient requirement implies a minimum 
OEI

[[Page 35738]]

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 are applicable to the 
GALP Model G250 airplane. Should GALP apply at a later date for a 
change to the type certificate to include another model incorporating 
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 the GALP Model G250 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.
    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.

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 GALP Model G250 airplane.
    For approval to use the power provided by the ATTCS to determine 
the approach climb performance limitations, the GALP Model G250 
airplane must comply with the requirements of Sec.  25.904 and Appendix 
I to Part 25, including the following requirements pertaining to the 
go-around phase of flight:
    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 to furnish cockpit information regarding 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:
    (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) will 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 OEI 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 simultaneous engine and ATTCS failure, the resulting minimum 
approach climb flight path intersects a flight path corresponding to 
the part 25 minimum, OEI approach climb gradient. The all-engines-
operating, go-around flight path, and the part 25 OEI approach climb 
gradient flight path, both 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 OEI approach 
climb performance data are presented in the Airplane Flight Manual.
    c. The critical time interval is illustrated in the following 
figure:

[[Page 35739]]

[GRAPHIC] [TIFF OMITTED] TR20JN11.002

    * The engine-and-ATTCS failed time interval must be no shorter 
than the time interval from the point of simultaneous engine and 
ATTCS failure to a height of 400 feet used to comply with I25.2(b) 
for ATTCS use during takeoff.

    Issued in Renton, Washington on June 13, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-15175 Filed 6-17-11; 8:45 am]
BILLING CODE 4910-13-P