81 FR 64360 - Special Conditions: The Boeing Company Model 787-10 Airplane; Aeroelastic Stability Requirements, Flaps-Up Vertical Modal-Suppression System
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration Federal Register Volume 81, Issue 182 (September 20, 2016)
Federal Aviation Administration
Federal Register Volume 81, Issue 182 (September 20, 2016)
| Page Range | 64360-64364 | |
| FR Document | 2016-22547 |
[Federal Register Volume 81, Number 182 (Tuesday, September 20, 2016)] [Proposed Rules] [Pages 64360-64364] From the Federal Register Online [www.thefederalregister.org] [FR Doc No: 2016-22547] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No. FAA-2016-6137; Notice No. 25-16-05-SC] Special Conditions: The Boeing Company Model 787-10 Airplane; Aeroelastic Stability Requirements, Flaps-Up Vertical Modal-Suppression System AGENCY: Federal Aviation Administration (FAA), DOT. [[Page 64361]] ACTION: Notice of proposed special conditions. ----------------------------------------------------------------------- SUMMARY: This action proposes special conditions for the Boeing Company (Boeing) Model 787-10 airplane. This airplane will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport-category airplanes. This design feature is a flaps-up vertical modal-suppression system. 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 November 4, 2016. ADDRESSES: Send comments identified by docket number FAA-2016-6137 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: Wael Nour, FAA, Airframe and Cabin Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057- 3356; telephone 425-227-2143; facsimile 425-227-1320. 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 July 30, 2013, Boeing applied for an amendment to type certificate no. T00021SE to include the new Model 787-10 airplane. This airplane is a stretched-fuselage derivative of the 787-9, currently approved under type certificate no. T00021SE, with maximum single-class seating capacity of 440 passengers. The 787-10 has a maximum takeoff weight of 560,000 lbs and is powered by two General Electric GEnx-1B/P2 or Rolls-Royce Trent 1000 engines. Type Certification Basis Under the provisions of Title 14, Code of Federal Regulations (14 CFR) 21.101, Boeing must show that the Model 787-10 airplane meets the applicable provisions of the regulations listed in type certificate no. T00021SE or the applicable regulations in effect on the date of application for the change, except for earlier amendments as agreed upon by the FAA. In addition, the certification basis includes other regulations, special conditions, and exemptions that are not relevant to these proposed special conditions. Type certificate no. T00021SE will be updated to include a complete description of the certification basis for this airplane model. 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 787-10 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 or similar 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, these special conditions would also apply to the other model under Sec. 21.101. In addition to the applicable airworthiness regulations and special conditions, the Model 787-10 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. 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. 21.101. Novel or Unusual Design Features The Model 787-10 airplane will incorporate the following novel or unusual design features: A flaps-up vertical modal suppression system. Discussion The Boeing Model 787-10 will add a new flaps-up vertical modal- suppression (F0VMS) system to the Normal mode of the primary flight- control system (PFCS). The F0VMS system is needed to satisfy the flutter-damping margin requirements of Sec. 25.629 and the means-of- compliance provisions in advisory circular (AC) 25.629-1B. This system will be used in lieu of typical methods of improving the flutter characteristics of an airplane, such as increasing the torsional stiffness of the wing or adding wingtip ballast weights. The F0VMS system is an active modal-suppression system that will provide additional damping to an already stable, but low-damped, 3Hz symmetric wing, nacelle, and body aeroelastic mode of the airplane. This feedback-control system will compensate for a flutter-damping margin deficiency of the airplane and maintain adequate damping margins to flutter. The F0VMS system accomplishes this by oscillating the elevators, and, when needed, the flaperons. Because Boeing's flutter analysis shows that the 3Hz mode is stable and does not flutter, the F0VMS system is not an active flutter- suppression system, [[Page 64362]] but, rather, a damping-augmentation system. At this time, the FAA is not prepared to accept an active flutter-suppression system that suppresses a divergent flutter mode in the operational or design envelope of the airplane. This will be the first time an active modal-suppression system will be used to compensate for a flutter-damping margin deficiency for Sec. 25.629 compliance, and the FAA intends to take a conservative approach in the technology's application. The FAA considers the use of this new active modal-suppression system for flutter compliance to be novel or unusual when compared to the technology envisioned in the current airworthiness standards. Consequently, special conditions are required in consideration of the effects of this new system on the aeroelastic stability of the airplane, both in the normal and failed state, to maintain the level of safety intended by Sec. 25.629. The stretched body of the 787-10 degrades the 3Hz symmetric wing, nacelle, and body aeroelastic mode relative to the 787-9. The 3Hz aeroelastic mode of the 787-10 airplane without the F0VMS system does not meet the damping margin criteria of AC 25.629-1B within the operational envelope, as well as the design envelope, of the airplane. The 3Hz mode is not predicted to flutter, but has a lack of adequate flutter-damping margin for the airplane. Boeing has determined that typical methods of improving the flutter characteristics of the airplane, such as increasing the torsional stiffness of the wing or adding wingtip ballast weights, do not meet their business objectives. Consequently, Boeing is adding a new F0VMS system to the Normal mode of the Model 787-10 airplane PFCS to satisfy the flutter-damping margin requirements of Sec. 25.629, and means-of-compliance provisions contained in AC 25.629-1B. The F0VMS system will be active in certain parts of the flight envelope when the flaps are retracted. The F0VMS system is a feedback-control system that adds damping to the system's 3Hz mode by oscillating the elevators symmetrically. When the elevators are expected to be ineffective due to blowdown or other limitations, the flaperons are applied to augment or supplant elevator-control input. However, the flaperons are not as effective as the elevators in providing additional damping to the 3Hz mode. The F0VMS system will be an integral part of the PFCS Normal mode and use existing hardware, including inertial and air-data sensors. As such, the F0VMS system is expected to be as reliable as the Normal mode itself. In other words, any failures that would cause a loss of the F0VMS function would also cause a loss of the Normal mode. FAA issue paper SA-17, ``Command Signal Integrity,'' requires that the probability of an automatic change from Normal mode to a degraded mode of the PFCS should occur with a frequency less than 10-7 per flight hour, irrespective of flight phase. This reliability is acceptable for the F0VMS system meeting the flutter-damping margins of Sec. 25.629 and AC 25.629-1B, and the requirements of these special conditions. The F0VMS function is only available in the PFCS Normal mode, and not available in the Secondary or Direct modes. However, the PFCS Secondary and Direct modes include a simplified modal-suppression function, which provides additional damping margin. In addition to the Model 787-10 airplane needing the F0VMS functionality for flutter compliance, this functionality will also be used for active nacelle gust-load alleviation (NGLA), because the low damping exhibited by the 3Hz mode adversely affects nacelle gust loads. Therefore, the Boeing Model 787-9 airplane NGLA system will not need to be carried over to the Model 787-10 airplane. 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. Applicability As discussed above, these special conditions are applicable to the Boeing Model 787-10 airplane. Should Boeing 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. Conclusion This action affects only certain novel or unusual design features on one model series 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 0 Accordingly, the Federal Aviation Administration (FAA) proposes the following special conditions as part of the type certification basis for Boeing Model 787-10 airplanes. The following special conditions are proposed to address the aeroelastic stability of the 787-10 airplane with the F0VMS system as an integral part of the PFCS Normal mode: Analytical Flutter-Clearance Requirements 1. The airplane in the PFCS Normal mode (which includes F0VMS) must meet the nominal (no failures) flutter and aeroelastic stability requirements of Sec. 25.629(b)(1), and the damping-margin criteria of AC 25.629-1B, Section 7.1.3.3. Figure 1, below, illustrates the Damping versus Airspeed plot. a. The aeroservoelastic analysis must take into account the effect of the following items: i. Significant structural and aerodynamic nonlinearities. ii. Significant F0VMS nonlinearities, including control-surface rate and displacement saturation, and blowdown. iii. The range of design maneuver load factors. iv. Control surface freeplay. v. Any other items that may affect the performance of the F0VMS system in maintaining adequate modal damping margins. [[Page 64363]] [GRAPHIC] [TIFF OMITTED] TP20SE16.024 2. The airplane in the PFCS Normal mode, but with the F0VMS system inoperative, must exhibit a damping margin to flutter of 0.015g within the V D /MD envelope, linearly decreasing (in KEAS) to zero damping margin to flutter at 1.15 VD /1.15 MD , limited to Mach 1.0. That is, the 3Hz mode should not cross the g = 0.015 line below VD , or the g = 0.03 line below 1.15 VD , assuming the use of analysis Method 1 of AC 25.629-1B, Section 7.1.3.3. Figure 2, below, illustrates the Damping versus Airspeed plot. [[Page 64364]] [GRAPHIC] [TIFF OMITTED] TP20SE16.025 3. The airplane in the PFCS Normal mode (which includes F0VMS) must meet the fail-safe flutter and aeroelastic stability requirements of Sec. 25.629(b)(2), and the damping-margin criteria of AC 25.629-1B, Section 7.1.3.5. 4. The airplane in the PFCS Secondary and Direct modes must meet the fail-safe flutter and aeroelastic-stability requirements of Sec. 25.629(b)(2), and the damping-margin criteria of AC 25.629-1B, Section 7.1.3.5. Issued in Renton, Washington, on September 9, 2016. Michael Kaszycki, Assistant Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2016-22547 Filed 9-19-16; 8:45 am] BILLING CODE 4910-13-P
![64360 Federal Register / Vol. 81, No. 182 / Tuesday, September 20, 2016 / Proposed Rules
the Director, when promulgating U.S.C. 4518(e) and 4526, FHFA party admits culpability with respect to
regulations relating to the Banks, to proposes to amend part 1231 of them; or
consider the differences between Fannie subchapter B of chapter XII of title 12 (iii) Is subject to a final prohibition
Mae and Freddie Mac (collectively, the of the CFR as follows: order under 12 U.S.C. 4636a.
Enterprises) and the Banks with respect (3) Amounts due under an
to: the Banks’ cooperative ownership PART 1231—GOLDEN PARACHUTE indemnification agreement entered into
structure; mission of providing liquidity AND INDEMNIFICATION PAYMENTS with a named entity-affiliated party on
to members; affordable housing and or prior to [DATE OF PUBLICATION OF
community development mission; ■ 1. The authority citation for part 1231
THE FINAL RULE IN THE FEDERAL
capital structure; joint and several continues to read as follows:
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liability; and any other differences the Authority: 12 U.S.C. 4518(e), 4518a, 4526. (c) Process; factors. With respect to
Director considers appropriate. See 12 ■ 2. In § 1231.2 add the definitions of payments under paragraph (b)(2) of this
U.S.C. 4513(f). In preparing this 2016 ‘‘Indemnification payment’’ and section:
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considered the differences between the alphabetical order to read as follows: regulated entity or the OF must conduct
Banks and the Enterprises as they relate a due investigation and make a written
to the above factors, and determined § 1231.2 Definitions. determination in good faith that:
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conservatorship (or receivership or a OF for the benefit of any current or OF; and
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V. Paperwork Reduction Act Liability or legal expense means— OF.
(1) Any legal or other professional (2) The entity-affiliated party may not
This proposed rulemaking does not expense incurred in connection with participate in the board’s deliberations
contain any information collection any claim, proceeding, or action; or decision.
requirement that requires the approval (2) The amount of, and the cost (3) If a majority of the board are
of the Office of Management and Budget incurred in connection with, any respondents in the action, the remaining
(OMB) under the Paperwork Reduction settlement of any claim, proceeding, or board members may approve payment
Act (44 U.S.C. 3501 et seq.). Therefore, action; and after obtaining written opinion of
FHFA has not submitted any (3) The amount of, and any cost outside counsel that the conditions of
information to OMB for review. incurred in connection with, any this regulation have been met.
VI. Regulatory Flexibility Act judgment or penalty imposed with (4) If all of the board members are
respect to any claim, proceeding, or respondents, they may approve payment
The Regulatory Flexibility Act (5 action.
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* * * * * outside counsel that the conditions of
regulation that has a significant
■ 3. Add § 1231.4 to read as follows: this regulation have been met.
economic impact on a substantial
number of small entities, small § 1231.4 Indemnification payments. (d) Scope. This section does not apply
businesses, or small organizations must to a regulated entity operating in
(a) Prohibited indemnification
include an initial regulatory flexibility conservatorship or receivership or to a
payments. Except as permitted in
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paragraph (b) of this section, a regulated
impact on small entities. Such an entity or the OF may not make Dated: September 13, 2016.
analysis need not be undertaken if the indemnification payments with respect Melvin L. Watt,
agency has certified that the regulation to an administrative proceeding or civil Director, Federal Housing Finance Agency.
will not have a significant economic action that has been initiated by FHFA. [FR Doc. 2016–22483 Filed 9–19–16; 8:45 am]
impact on a substantial number of small (b) Permissible indemnification BILLING CODE 8070–01–P
entities. 5 U.S.C. 605(b). FHFA has payments. A regulated entity or the OF
considered the impact of the 2016 may pay:
proposed rulemaking under the (1) Premiums for professional liability
Regulatory Flexibility Act. The General insurance or fidelity bonds for directors DEPARTMENT OF TRANSPORTATION
Counsel of FHFA certifies that this 2016 and officers, to the extent that the
proposed rulemaking, if adopted as a insurance or fidelity bond covers Federal Aviation Administration
final rule, is not likely to have a expenses and restitution, but not a
significant economic impact on a judgment in favor of FHFA or a civil 14 CFR Part 25
substantial number of small entities money penalty.
because it would apply primarily to the [Docket No. FAA–2016–6137; Notice No. 25–
(2) Expenses of defending an action,
16–05–SC]
regulated entities and the OF, which are subject to the entity-affiliated party’s
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not small entities for purposes of the agreement to repay those expenses if the Special Conditions: The Boeing
Regulatory Flexibility Act. entity-affiliated party either: Company Model 787–10 Airplane;
(i) When the proceeding results in an Aeroelastic Stability Requirements,
List of Subjects in 12 CFR Part 1231
order, is not exonerated of the charges Flaps-Up Vertical Modal-Suppression
Indemnification payments, that the expenses specifically relate to; System
Government-sponsored enterprises. or
Accordingly, for reasons stated in the (ii) Enters into a settlement of those AGENCY:Federal Aviation
preamble, under the authority of 12 charges in which the entity-affiliated Administration (FAA), DOT.
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Document Created: 2018-02-09 13:20:10
Document Modified: 2018-02-09 13:20:10
| Category | Regulatory Information | |
| Collection | Federal Register | |
| sudoc Class | AE 2.7: GS 4.107: AE 2.106: | |
| Publisher | Office of the Federal Register, National Archives and Records Administration | |
| Section | Proposed Rules | |
| Action | Notice of proposed special conditions. | |
| Dates | Send your comments on or before November 4, 2016. | |
| Contact | Wael Nour, FAA, Airframe and Cabin Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057- 3356; telephone 425-227-2143; facsimile 425-227-1320. | |
| FR Citation | 81 FR 64360 | |
| CFR Associated | Aircraft; Aviation Safety and Reporting and Recordkeeping Requirements |
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