### 49936 Federal Register / Vol. 80, No. 159 / Tuesday, August 18, 2015 / Proposed Rules

Conclusion

This action affects only certain novel or unusual design features on Gulfstream Model GVII–G500 airplanes. It is not a rule of general applicability.

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 Proposed Special Conditions

The current airworthiness regulations pertaining to pilot strength and controllability for conventional-control column-and-wheel designs do not adequately address the side-stick controllers proposed for the Gulfstream Model GVII–G500 airplane. Accordingly, the FAA proposes the following special conditions as part of the type certification basis for Gulfstream GVII–G500 airplanes, in lieu of §§ 25.143(d), 25.143(i)(2), 25.145(b), 25.173(c), 25.175(b), and 25.175(d):

Pilot strength: In lieu of the controlforce limits shown in § 25.143(d) for pitch and roll, and in lieu of specific pitch-force requirements of §§ 25.143(i)(2), 25.145(b), 25.173(c), 25.175(b), and 25.175(d), Gulfstream must show that the temporary and maximum prolonged-force levels for the
side-stick controllers are suitable for all expected operating conditions andconfigurations, whether normal or nonnormal.

Pilot-control authority: The electronic side-stick-controller coupling design must provide for corrective and overriding control inputs by either pilot
with no unsafe characteristics.
Annunciation of the controller status must be provided, and must not be confusing to the flightcrew.

Pilot control: Gulfstream must show by flight tests that the use of side-stick controllers does not produce unsuitable pilot-in-the-loop control characteristics when considering precision path control and tasks, and turbulence. In addition, pitch and roll control force and displacement sensitivity must be compatible, so that normal pilot inputs
on one control axis will not cause significant unintentional inputs (crossover) on the other.

Issued in Renton, Washington, on August

5, 2015. Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2015–20298 Filed 8–17–15; 8:45 am]

**BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION** 

**Federal Aviation Administration**

**14 CFR Part 25**

**[Docket No. FAA–2015–1482; Notice No. 25– 15–08–SC]** 

**Special Conditions: Gulfstream Model GVII–G500 Airplanes, Automatic Speed**  **Protection for Design Dive Speed**

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed special
conditions.

**SUMMARY :**  This action proposes special
conditions for the Gulfstream Model GVII–G500 airplanes. These airplanes will have a novel or unusual design
feature associated with a reduced margin between design cruising speed,

V C /M C , and design diving speed, V D /

M D , based on the incorporation of a high-speed protection system that limits nose-down pilot authority at speeds
above V C /M C . The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed 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 :**  Send your comments on or before October 2, 2015.

**ADDRESSES :**  Send comments identified by docket number FAA–2015–1482 using any of the following methods:

• Federal eRegulations Portal: Go to http://www.regulations.gov/ and follow the online instructions for sending your comments electronically.

• Mail: Send comments to Docket Operations, M–30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room W12–140, West Building Ground Floor, Washington, DC

20590–0001.

• Hand Delivery or Courier: Take comments to Docket Operations in Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

• Fax: Fax comments to Docket Operations at 202–493–2251.

Privacy: The FAA will post all comments it receives, without change,

to http://www.regulations.gov/

, including any personal information the commenter provides. Using the search function of the docket Web site, anyone
can find and read the electronic form of all comments received into any FAA docket, including the name of the individual sending the comment (or signing the comment for an association, business, labor union, etc.). DOT’s complete Privacy Act Statement can be
found in the Federal Register published on April 11, 2000 (65 FR 19477–19478),
as well as at http://DocketsInfo.dot .gov/

.

Docket: Background documents or comments received may be read at http://www.regulations.gov/ at any time.
Follow the online instructions for accessing the docket or go to Docket Operations in Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

**FOR FURTHER INFORMATION CONTACT :**  Walt Sippel, FAA, Airframe and Cabin Safety Branch, ANM–115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057–3356; telephone 425–227–2774; facsimile

425–227–1232.

**SUPPLEMENTARY INFORMATION :** 

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 will consider all comments we receive by the closing date for comments. We may change these special
conditions based on the comments we

receive.

Background

On March 29, 2012, Gulfstream Aerospace Corporation applied for a type certificate for their new Model GVII–G500 airplane. The Model GVII– G500 airplane will be a large-cabin business jet with seating for 19 passengers. It will incorporate a low, swept-wing design with winglets and a T-tail. The powerplant will consist of two aft-fuselage-mounted Pratt & Whitney turbofan engines. Avionics will include four primary display units and multiple touchscreen controllers. Theflight-control system is a three-axis, flyby-wire system incorporating active control/coupled side sticks.

The Model GVII–G500 will have a wingspan of approximately 87 feet and a length of just over 91 feet. Maximum takeoff weight will be approximately 76,850 pounds and maximum takeoff thrust will be approximately 15,135 pounds. Maximum range will be


### 49937 Federal Register / Vol. 80, No. 159 / Tuesday, August 18, 2015 / Proposed Rules

approximately 5,000 nautical miles, and maximum operating altitude will be 51,000 feet.

Type Certification Basis

Under the provisions ofTitle 14, Code of Federal Regulations (14 CFR) 21.17,
Gulfstream must show that the Model GVII–G500 airplane meets the applicable provisions of part 25 as amended by Amendments 25–1 through

25–137.

In addition, the certification basis includes other regulations, special conditions, and exemptions that are not relevant to these proposed special
conditions.

If the Administrator finds that the applicable airworthiness regulations ( i.e., 14 CFR part 25) do not contain adequate or appropriate safety standards for Model GVII–G500 airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 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 under § 21.101.

In addition to the applicable airworthiness regulations and special conditions, the Model GVII–G500 airplane must comply with the fuel-vent and exhaust-emission requirements of14 CFR part 34, and the noisecertification requirements of 14 CFR part 36; and the FAA must issue a finding of regulatory adequacy under § 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 § 11.38, and they become part of the type certification basis under § 21.17(a)(2).

Novel or Unusual Design Features

The Model GVII–G500 airplane will incorporate the following novel or unusual design features:

Gulfstream proposes to reduce the margin between V C /M C and V D /M D , required by 14 CFR 25.335(b), based on the incorporation of a high-speed protection system in the airplane’s flight-control laws. The high-speed protection system limits nose-down pilot authority at speeds above V C /M C , and prevents the airplane from performing the maneuver required under § 25.335(b)(1).

These proposed 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.

Discussion

Title 14, Code of Federal Regulations (14 CFR) 25.335(b)(1) is an analytical envelope condition which was originally adopted in Part 4b of the Civil Air Regulations to provide an acceptable speed margin between design cruise speed and design dive speed. Flutter clearance design speeds and airframe design loads are impacted by the design dive speed. While the initial condition for the upset specified in the rule is 1g level flight, protection is afforded for other inadvertent overspeed conditions as well. Section 25.335(b)(1) is intended as a conservative enveloping condition for potential overspeed conditions, including non-symmetric ones. To establish that potential overspeed conditions are enveloped, Gulfstream must demonstrate that any reduced speed margin based on the high-speed protection system in the Model GVII– G500 airplane will not be exceeded in inadvertent or gust-induced upsets resulting in initiation of the dive from non-symmetric attitudes; or that theairplane is protected by the flightcontrol laws from getting into nonsymmetric upset conditions. Gulfstream
must conduct a demonstration that includes a comprehensive set of
conditions as described below.

These special conditions are proposed in lieu of § 25.335(b)(1). Section 25.335(b)(2), which also addresses the design dive speed, is applied separately (Advisory Circular (AC) 25.335–1A provides an acceptable means of compliance to § 25.335(b)(2)).

Special conditions are necessary to address the Model GVII–G500 airplane high-speed protection system.These proposed special conditions identify various symmetric and non-symmetric
maneuvers that will ensure that an appropriate design dive speed, V D /M D , is established.

Special Condition 2 of these proposed special conditions references AC 25–7C, section 8, paragraph 32, ‘‘Gust Upset,’’
included here for reference:

In the following three upset tests, the values of displacement should be appropriate to the airplane type and should depend upon airplane stability
and inertia characteristics. The lower and upper limits should be used for airplanes with low and high maneuverability, respectively.

(i) With the airplane trimmed in wings-level flight, simulate a transient gust by rapidly rolling to the maximum bank angle appropriate for the airplane, but not less than 45 degrees nor more than 60 degrees. The rudder and longitudinal control should be held fixed during the time that the required bank is being attained. The rolling velocity should be arrested at this bank angle. Following this, the controls
should be abandoned for a minimum of
3 seconds after VMO /M MO , or after 10 seconds, whichever occurs first.

(ii) Perform a longitudinal upset from normal cruise. Airplane trim is
determined at VMO /M MO using power and thrust required for level flight, but
with not more than maximum continuous power and thrust. This is followed by a decrease in speed, after which an attitude of 6 to l2 degrees nose down, as appropriate for the airplane type, is attained with the power, thrust, and trim initially required for VMO /M MO in level flight. The airplane is permitted
to accelerate until 3 seconds after VMO /

M MO . The force limits of § 25.143(d) for short term application apply.

(iii) Perform a two-axis upset, consisting of combined longitudinal and lateral upsets. Perform the longitudinal upset, as in paragraph (ii) above, and when the pitch attitude is set, but before reaching VMO /M MO , roll the airplane to between 15 and 25 degrees. The
established attitude should be
maintained until 3 seconds after VMO /

M MO

.

Special Conditions 3 and 4 of these proposed special conditions indicate that failures of the high-speed protection system must be improbable and must be annunciated to the pilots. If these two criteria are not met, then the probability that the established dive speed will be exceeded, and the resulting risk to the airplane, are toogreat. On the other hand, if the highspeed protection system is known to be inoperative, then dispatch of the airplane may be acceptable as allowed by proposed Special Condition 5. Dispatch would only be acceptable if appropriate reduced operating speeds,

VMO /M MO , as well as the overspeed warning for exceeding those speeds, are provided in both the airplane flight manual and on the flightdeck display, and are equivalent to that of the normal airplane with the high-speed protection system operative.

We do not believe that application of the ‘‘Interaction of Systems and Structures’’ Special Conditions (reference GVI Issue Paper A–2), or EASA Certification Specification 25.302, are appropriate in this case, because design dive speed is, in and of itself, part of the design criteria. Stability and control, flight loads, and flutter evaluations all depend on the design dive speed. Therefore, a single design dive speed should be established


### 49938 Federal Register / Vol. 80, No. 159 / Tuesday, August 18, 2015 / Proposed Rules

that will not be exceeded, taking intoaccount the performance of the highspeed protection system as well as its failure modes, failure indications, and accompanying flight-manual

instructions.

Applicability

As discussed above, these special conditions are applicable to the Model GVII–G500 airplane. Should Gulfstream 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 one model of airplane. It is not a rule of general applicability.

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 Proposed Special Conditions

■ Accordingly, the Federal Aviation Administration (FAA) proposes the following special conditions as part of the type certification basis for Gulfstream Model GVII–G500 airplanes.

1. In lieu of compliance with § 25.335(b)(1), if the flight-control system includes functions that act automatically to initiate recovery before the end of the 20-second period specified in § 25.335(b)(1), VD /M D must be determined from the greater of the speeds resulting from conditions (a) and (b) of these special cConditions. The speed increase occurring in these maneuvers may be calculated if reliable or conservative aerodynamic data are
used.

(a) From an initial condition of stabilized flight at V C /M C , the airplane is upset so as to take up a new flight path 7.5 degrees below the initial path. Control application, up to full authority, is made to try to maintain this new flight path. Twenty seconds after initiating the upset, manual recovery is made at a load factor of 1.5g (0.5 acceleration increment), or such greater load factor that is automatically applied by the system with the pilot’s pitch control neutral. Power, as specified in § 25.175(b)(1)(iv), is assumed until recovery is initiated, at which timepower reduction, and the use of pilotcontrolled drag devices, may be used. (b) From a speed below V C /M C , with power to maintain stabilized level flight at this speed, the airplane is upset so as to accelerate through V C /M C at a flight path 15 degrees below the initial path (or at the steepest nose-down attitude that the system will permit with full control authority if less than 15 degrees). The pilot’s controls may be in the neutral position after reaching V C /

M C and before recovery is initiated. Recovery may be initiated 3 seconds after operation of the high-speed warning system by application of a load of 1.5g (0.5 acceleration increment), or such greater load factor that is automatically applied by the system with the pilot’s pitch control neutral. Power may be reduced simultaneously. All other means of decelerating the airplane, the use of which is authorized up to the highest speed reached in the maneuver, may be used. The interval between successive pilot actions must
not be less than 1 second.

2. The applicant must also demonstrate that the speed margin, established as above, will not be exceeded in inadvertent or gust-induced upsets resulting in initiation of the dive from non-symmetric attitudes, unlessthe airplane is protected by the flightcontrol laws from getting into nonsymmetric upset conditions. The upset maneuvers described in Advisory Circular 25–7C, ‘‘Flight Test Guide for Certification of Transport Category Airplanes,’’ section 8, paragraph 32, sub-paragraphs c(3)(a), (b), and (c), may be used to comply with this requirement.

3. The probability of any failure of the high-speed protection system, which would result in an airspeed exceeding those determined by Special Conditions 1 and 2, must be less than 10

¥ 5 per flight hour.

4. Failures of the system must be annunciated to the pilots. Flight manual instructions must be provided that reduce the maximum operating speeds,

VMO /M MO . With the system failed, the operating speed must be reduced to a value that maintains a speed margin
between VMO /M MO and V D /M D , and that is consistent with showing compliance with § 25.335(b) without the benefit of the high-speed protection system.

5. The applicant may request that the Master Minimum Equipment List relief for the high-speed protection system be considered by the FAA Flight Operations Evaluation Board, provided that the flight manual instructions indicate reduced maximum operating speeds as described in Special Condition 4. In addition, the flightdeck display of the reduced operating speeds, as well as the overspeed warning for exceeding those speeds, must be equivalent to that of the normal airplane with the high-speed protection system operative. Also, the applicant must
show that no additional hazards are introduced with the high-speed protection system inoperative.

Issued in Renton, Washington, on August

5, 2015. Michael Kaszycki, Acting Manager, Transport Airplane Directorate Aircraft Certification Service.

[FR Doc. 2015–20297 Filed 8–17–15; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 25**

**[Docket No. FAA–2015–2271; Notice No. 25– 15–06–SC]** 

**Special Conditions: Cessna Airplane Company Model 680A Airplane, Side**  **Facing Seats Equipped With Airbag Systems** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed special
conditions.

**SUMMARY :**  This action proposes special
conditions for the Cessna Model 680A airplane. This airplane will have novel or unusual design features when compared to the state of technology
envisioned in the airworthiness standards for transport-categoryairplanes. This design features sidefacing seats equipped with airbag systems. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed 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 :**  Send your comments on or before October 2, 2015.

**ADDRESSES :**  Send comments identified by docket number FAA–2015–2271 using any of the following methods:

• Federal eRegulations Portal: Go to http://www.regulations.gov/ and follow the online instructions for sending your comments electronically.

• Mail: Send comments to Docket Operations, M–30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room W12–140, West Building Ground Floor, Washington, DC

20590–0001.

• Hand Delivery or Courier: Take comments to Docket Operations in