[Federal Register Volume 86, Number 52 (Friday, March 19, 2021)]
[Rules and Regulations]
[Pages 14810-14812]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05447]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2021-0203; Special Conditions No. 25-784-SC]


Special Conditions: Lufthansa Technik, Boeing Model 787-8 
Airplane; Installation of Large, Non-Structural Glass in the Passenger 
Cabin

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 Boeing Model 787-8 
airplane. This airplane as modified by Lufthansa Technik, 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 the installation of large, 
non-structural glass in the passenger cabin. 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: This action is effective on Lufthansa Technik on March 19, 2021. 
Send comments on or before May 3, 2021.

ADDRESSES: Send comments identified by Docket No. FAA-2021-0203 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 website, 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).
    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: Shannon Lennon, Human Machine 
Interface Section, AIR-626, Transport Standards Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 2200 South 216th Street, Des Moines, Washington 98198; 
telephone and fax 206-231-3209; email [email protected].

SUPPLEMENTARY INFORMATION: The substance of these special conditions 
has been published in the Federal Register for public comment in 
several prior instances with no substantive comments received. 
Therefore, the FAA has determined that prior public notice and comment 
are unnecessary, and finds that, for the same reason, good cause exists 
for adopting these special conditions upon publication in the Federal 
Register.

Comments Invited

    The FAA invites 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.
    The FAA will consider all comments received by the closing date for 
comments. The FAA may change these special conditions based on the 
comments received.

Background

    On September 27, 2019, Lufthansa Technik applied for a supplemental 
type certificate for installation of large, non-structural glass in the 
passenger cabin in the Boeing Model 787-8 airplane. The Boeing Model 
787-8 is a twin-engine, transport category airplane, with capacity for 
381 passengers, and a maximum takeoff weight of 476,000 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Lufthansa Technik must show that the Boeing Model 787-8 
airplane, as changed, continues to meet the applicable provisions of 
the regulations listed in Type Certificate No. TC 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.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Boeing Model 787-8 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 applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
these special conditions would also apply to the other model under 
Sec.  21.101.

[[Page 14811]]

    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 787-8 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 Boeing Model 787-8 airplane will incorporate the following 
novel or unusual design features:
    Lufthansa Technik is proposing to install large non-structural 
glass items in Model 787-8 airplanes. Possible installations of large 
non-structural glass items include, but are not limited to, the 
following items:
     Glass partitions.
     Glass floor installations.
     Glass attached to the ceiling.
     Glass parts integrated in the stairway.
     Wall or Door mounted mirrors and glass panels.
     Mirrors as part of a door blow out panel.
     Glass plate installed in a doorframe.
     Washstand with glass-panel.
    The installation of these glass items in the passenger compartment, 
which can be occupied during taxi, take-off and landing (TT&L), is a 
novel or unusual design feature with respect to the installed material. 
The applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for this design features.

Discussion

    The use of glass results in trade-offs between the one unique 
characteristic of glass--its capability for undistorted or controlled 
light transmittance, or transparency--and the negative aspects of the 
material. Glass, in its basic form as annealed, untreated sheet, plate, 
or float glass, when compared to metals, is extremely notch-sensitive, 
has a low fracture resistance, has a low modulus of elasticity, and can 
be highly variable in its properties. While reasonably strong, it is 
nonetheless not a desirable material for traditional airplane 
applications because it is heavy (about the same density as aluminum), 
and when it fails, it breaks into extremely sharp fragments that have 
the potential for injury, and which have been known to be lethal. Thus, 
the use of glass traditionally was limited to windshields, and 
instrument or display transparencies. The regulations in Sec.  25.775 
only address, and likewise only recognize, the unique use of glass in 
windshield or window applications where no other material will serve. 
This regulation does address the adverse properties of glass, but 
pilots occasionally are injured from shattered glass windshields.
    The FAA divides other uses of glass in the passenger cabin into 
four groups. These groups were created to address the practical and 
functional uses of glass. The four groups are as follows:
    The first group is glass items installed in rooms or areas in the 
cabin that are not occupied during TT&L, and a person does not have to 
enter or pass through the room or area to get to any emergency exit.
    The second group is glass integrated into a functional device the 
operation of which is dependent upon the characteristics of glass, such 
as instrument or indicator protective transparencies, or monitor 
screens such as liquid crystal displays or plasma displays. This group 
may be installed in any area in the cabin regardless of occupancy 
during TT&L. Acceptable means of compliance for these items may depend 
on the size and specific location of the device containing the glass.
    The third group is small glass items installed in occupied rooms or 
areas during TT&L, or rooms or areas that a person does not have to 
enter or pass through to get to any emergency exit. The FAA defines a 
small glass item as less than 8.8 lbs (4 kg) in mass.
    The fourth group is large glass items, the subject of these special 
conditions, installed in occupied rooms or areas during TT&L, or rooms 
or areas that a person must enter or pass through to get to any 
emergency exit. A large glass item is defined as 8.8 lbs (4 kg) or 
greater in mass. Groups of glass items that collectively weigh 4 kg or 
more would also be included. The mass is based on the amount of glass 
that becomes hazardous in high inertial loads.
    The glass items in groups one, two, and three are restricted to 
applications where the potential for injury is either highly localized, 
such as flight-instrument faces, or the location is such that injury 
due to failure of the glass is unlikely, for example mirrors in 
lavatories, because these installations necessitate the use of glass. 
These glass items typically are addressed in a method-of-compliance 
issue paper for each project based on existing part 25 regulations, or 
in established policy. These issue papers identify specific tests that 
could include abuse loading and ball-impact testing. In addition, these 
items are subject to the inertia loads contained in Sec.  25.561, and 
maximum positive-differential pressure for items like video monitors to 
meet Sec.  25.789.
    The items in group four are much larger and heavier than previously 
approved, and raise additional safety concerns. These large, heavy 
glass panels, primarily installed as architectural features, were not 
envisioned in the regulations. The unique aspects of glass, with the 
potential to become highly injurious or lethal objects during emergency 
landing, minor crash conditions, or in flight, warrant a unique 
approach to certification that addresses the characteristics of glass 
that prevented its use in the past. These special conditions were 
developed to ensure that airplanes with large glass features in 
passenger cabins provide the same level of safety as airplanes using 
traditional, lightweight materials. The FAA reiterates this intention 
in the text of the special conditions by qualifying their use for group 
four glass items.
    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.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 787-8 airplane. Should Lufthansa Technik apply at a later 
date for a supplemental type certificate to modify any other model 
included on Type Certificate No. T00021SE to incorporate the same novel 
or unusual design feature, these special conditions would apply to that 
model as well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on one model of 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.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

Authority Citation

    The authority citation for these special conditions is as follows:

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

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the

[[Page 14812]]

Administrator, the following special conditions are issued as part of 
the type certification basis for Boeing Model 787-8 airplanes, as 
modified by Lufthansa Technik.
    For large glass items (a single item, or a collective group of 
glass items, that weigh 4 kg or more in mass) installed in passenger-
occupied rooms or areas during taxi, takeoff, and landing, or installed 
in rooms or areas that occupants must enter or pass through to access 
any emergency exit, the glass installations on the Lufthansa Model 787-
8 airplane must meet the following conditions:
    1. Material Fragmentation--The applicant must use tempered or 
otherwise treated glass to ensure that, when fractured, the glass 
breaks into small pieces with relatively dull edges. The glass 
component installation must retain all glass fragments to minimize the 
danger from flying glass shards or pieces. The applicant must 
demonstrate this characteristic by impact and puncture testing, and 
testing to failure. The applicant may conduct this test with or without 
any glass coating that may be used in the design.
    2. Strength--In addition to meeting the load requirements for all 
flight and landing loads, including any of the applicable emergency-
landing conditions in subparts C & D of 14 CFR part 25, the glass 
components that are located such that they are not protected from 
contact with cabin occupants must not fail due to abusive loading, such 
as impact from occupants stumbling into, leaning against, sitting on, 
or performing other intentional or unintentional forceful contact with 
the glass component. The applicant must assess the effect of design 
details such as geometric discontinuities or surface finish, including 
but not limited to embossing and etching.
    3. Retention--The glass component, as installed in the airplane, 
must not come free of its restraint or mounting system in the event of 
an emergency landing, considering both the directional loading and 
resulting rebound conditions. The applicant must assess the effect of 
design details such as geometric discontinuities or surface finish, 
including but not limited to embossing and etching.
    4. Instruction for Continued Airworthiness--The instructions for 
continued airworthiness must reflect the method used to fasten the 
panel to the cabin interior, and must ensure the reliability of the 
methods used (e.g., life limit of adhesives, or clamp connection). The 
applicant must define any inspection methods and intervals based upon 
adhesion data from the manufacturer of the adhesive, or upon actual 
adhesion-test data, if necessary.

    Issued in Des Moines, Washington, on March 11, 2021.
Patrick Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2021-05447 Filed 3-18-21; 8:45 am]
BILLING CODE 4910-13-P