[Federal Register Volume 79, Number 170 (Wednesday, September 3, 2014)]
[Rules and Regulations]
[Pages 52169-52171]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-20865]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2014-0419; Special Conditions No. 25-563-SC]


Special Conditions: Gulfstream Aerospace Corporation, Model GVI; 
Electro-Hydraulically Actuated Seats Equipped With a Backup Power 
Supply

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special condition; request for comments.

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SUMMARY: These special conditions are issued for Gulfstream Aerospace 
Corporation Model GVI airplane. This airplane, as modified by 
Gulfstream Aerospace Corporation, will have novel or unusual design 
features associated with the installation of electro-hydraulically 
operated seats with a backup power supply (BPS) and hydraulic 
reservoir, pump, and actuators, as well as massage and heating 
functions. The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for these design features. 
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 September 3, 
2014. We must receive your comments by October 20, 2014.

ADDRESSES: Send comments identified by docket number FAA-2014-0419 
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.

[[Page 52170]]

     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 the 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: Dan Jacquet, FAA, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057-
3356; telephone 425-227-2676; facsimile 425-227-1320.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and 
opportunity for prior public comment on, these special conditions is 
impracticable because these procedures would significantly delay 
issuance of the design approval and thus delivery of the affected 
aircraft. The FAA therefore finds that good cause exists for making 
these special conditions effective upon publication in the Federal 
Register.

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 June 14, 2014, Gulfstream Aerospace Corporation applied for an 
amendment to a Supplemental Type Certificate (STC) ST04252AT-D for the 
installation of electro-hydraulically operated seats with novel or 
unusual features in the Model GVI airplane. These features include a 
backup power supply used to return the backrest, seat pan, and leg rest 
to the taxi, takeoff, and landing (TT&L) position in the event of a 
power failure. In addition, each seat contains a hydraulic reservoir, 
pump, and actuators, as well as massage and heating functions. The 
Model GVI is a business jet airplane powered by two Rolls-Royce 
Deutschland Ltd. and Company KG turbofan engines and is certified for 
19 passengers and a crew of 3.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulation (14 
CFR) 21.101, Gulfstream Aerospace Corporation must show that the Model 
GVI, as changed, continues to meet the applicable provisions of the 
regulations incorporated by reference in Type Certificate No. T00015AT 
or the applicable regulations in effect on the date of application for 
the change. The regulations incorporated by reference in the type 
certificate are commonly referred to as the ``original type 
certification basis.'' The regulations incorporated by reference in 
Type Certificate No. T00015AT are as follows:
     14 CFR part 25, Airworthiness Standards: Transport 
Category Airplanes, effective February 1, 1965, including Amendments 
25-1 through 25-120 and 25-122, 25-124, and 25-132. Amendment 25-118 
was not published and therefore has no applicability.
     14 CFR part 36, Noise Standards: Aircraft Type and 
Airworthiness Certification, effective December 1, 1969, including 
Amendments 36-1 through 36-28.
     Compliance with Section 44715(e) of Title 49 U.S.C. (Noise 
Control Act of 1972).
     Optional Design Regulations:
    (a) The Model GVI has been shown to comply with the requirements 
for ditching: Sec. Sec.  25.801, 25.563, 25.807(e), and 25.1585(a). 
When the operating rules require emergency ditching equipment, 
compliance with Sec. Sec.  25.1411 and 25.1415 must be shown. 
Gulfstream Report GVI-GER-1709, ``Design Requirements Document for 
Ditching Equipment,'' provides an acceptable means for showing 
compliance with Sec. Sec.  25.1411 and 25.1415.
    (b) The Model GVI is approved for flight into known icing 
conditions and has demonstrated compliance to Sec.  25.1419.
     Exemptions pertinent to these special conditions: 
Exemption No. 9761, Sec. Sec.  25.562(a) and 25.785(b), Side Facing 
Divan.
    In addition, the certification basis includes certain special 
conditions, exemptions, and equivalent safety findings 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 the Gulfstream Model GVI because of a 
novel or unusual design feature, special conditions are prescribed 
under the provisions of 14 CFR 21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for a STC to modify any 
other model included on the same type certificate to incorporate 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 Gulfstream Model GVI 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 14 CFR 21.101.

Novel or Unusual Design Features

    The Gulfstream Model GVI will incorporate the following novel or 
unusual design features: Hydraulically-actuated components on airplane 
seats including hydraulic reservoir, pump, and actuators, as well as 
massage and heating functions and backup power systems.

Discussion

    Hydraulically-actuated components and backup power systems on 
airplane seats are considered novel or unusual by the FAA. Therefore, 
we developed special conditions that contain the additional standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.
    The FAA has considered the installation of seats with these 
features to have four primary safety concerns:

[[Page 52171]]

    1. Reliability of the backup power supply;
    2. Safety hazards to the occupants from the hydraulically-actuated 
components of the seat;
    3. Structural integrity of the hydraulic components; and
    4. Flammability.
    Emergency exits must be accessible to the passengers and the 
effectiveness of evacuation must be maintained. Typical airplane seats 
can be manually positioned to the lateral (track) and directional 
(swivel) TT&L position by mechanical means, so they can be positioned 
in the event of a loss of cabin power. For this electro-hydraulically 
operated seat design, in lieu of a manual means to re-position the 
hydraulically operated seat features (backrest, seat pan, and leg rest 
deployment) for TT&L, a BPS is used to temporarily power the hydraulic 
system. The BPS is only intended for use in the event of a loss of 
cabin power. If the seats are installed in the path of the emergency 
over wing exits, failure to return the seat to a TT&L position may have 
an adverse effect on evacuation. Substantiation of 14 CFR 25.809(b) and 
25.813(c)(2)(ii) must be shown with the seats in their most adverse 
positions.
    It must be shown that the hydraulically-actuated components of the 
seat pose no safety hazard to the occupants or airplane. This includes 
injuries caused by crushing of airplane occupants who are between the 
hydraulically-actuated components and any part of the passenger cabin 
when seat features (e.g., leg rest or backrest) are actuated. 
Additionally, the risk of loss of function of a control or proximity 
switch resulting in the pump motor being commanded to stay on, after 
the hydraulic actuator(s) have reached their maximum/minimum limit, 
must not cause the overloaded motor to overheat, as it could catch 
fire.
    The FAA has also considered the emergency landing dynamic 
conditions for the installation of electro-hydraulically actuated 
seats. The applicant must show that the hydraulic system (actuators, 
reservoir, lines, etc.) remains intact and free from leakage under the 
conditions specified in Sec.  25.562. Testing of each seat's hydraulic 
system per Sec.  25.1435(c) may be conducted off of the airplane.
    Flammability of hydraulic fluid used in the seat movement mechanism 
must be considered. If the fluid is flammable, it could contribute to a 
post-crash or in-flight fire. Any failure modes that would result in 
release of the flammable hydraulic fluid during a post-crash or in-
flight fire causing such fluid to materially increase an existing fire 
must be examined. Examples of this could be flex lines burning through 
and releasing the flammable hydraulic fluid, or the fluid reservoir 
could be heated in a fire resulting in a boiling liquid expanding vapor 
explosion. The potential for spontaneous ignition of the fluid coming 
into contact with hot surfaces or other ignition sources should also be 
addressed. The applicant should examine any possible failure mode in 
which the flammable hydraulic fluid could be absorbed into materials, 
like the seat foam/fabric, carpeting, etc. The applicant must show that 
any fluid-soaked seat parts are still self-extinguishing. The applicant 
must also show that flammability of dry residue, which may be present 
from a slow leak/fluid weepage, does not degrade the flammability 
characteristics of any materials it may come into contact with to a 
level below the requirements specified in Sec.  25.853.

Applicability

    As discussed above, these special conditions are applicable to STC 
ST04252AT-D, which modifies the Gulfstream Model GVI airplane. Should 
Gulfstream Aerospace Corporation apply at a later date to amend this 
STC to incorporate the same novel or unusual design feature, the 
special conditions would apply to that amended STC as well.

Conclusion

    This action affects only certain novel or unusual design features 
on one airplane model. 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.
    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 
modification to the Gulfstream Model GVI airplane is imminent, the FAA 
finds that good cause exists to make these special conditions effective 
upon publication in the Federal Register.

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 Gulfstream Aerospace Corporation 
airplanes modified by Gulfstream Aerospace Corporation.

Electro-Hydraulically Actuated Seats Equipped With a Backup Power 
Supply

    1. The probability of failure of the backup power supply to return 
seat components to the required taxi, takeoff, and landing position 
must be shown to be no greater than 10-5 per flight hour.
    2. It must be shown that the hydraulically-actuated components of 
the seat pose no safety hazard to the occupants. Hazards to be 
considered per the latest revision of Advisory Circular 25.1309-1, at a 
minimum are:
    a. Injuries caused by crushing of airplane occupants who are 
between the hydraulically actuated components and any part of the 
passenger cabin when the leg rest or backrest is actuated.
    b. The risk of loss of function of a control or proximity switch 
resulting in the pump motor being commanded to stay on after the 
hydraulic actuator(s) have reached their maximum/minimum limit, 
creating potential for overheat or fire.
    c. The potential for a significant contribution to a fire in the 
event fluid comes into contact with hot surfaces or other ignition 
sources, and the potential for release of toxic or flammable vapors/
gasses.
    3. It must be shown that the hydraulic system (actuators, 
reservoir, lines, etc.) remains intact and free from leakage under the 
conditions specified in Sec.  25.562. Testing of each seat's hydraulic 
system per Sec.  25.1435(c) may be conducted off of the airplane.
    4. Section 25.863 requires consideration of any effects the fluid, 
including the fluid as a dry residue, could have on combustible or 
absorbing materials. The characteristics of the flammable fluid in 
these conditions must be tested to the requirements of Sec.  25.853(a) 
and (c), or the materials must be shielded in a manner that prevents 
contact by the fluid. However, as an alternative to such testing or 
shielding, the applicant may provide, in accordance with Sec.  
25.863(c), a quick-acting means that alerts the crew that the fluid has 
leaked.

    Issued in Renton, Washington, on August 26, 2014.
Michael Kaszycki,
Assistant Manager, Transport Airplane Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-20865 Filed 9-2-14; 8:45 am]
BILLING CODE 4910-13-P