[Federal Register Volume 88, Number 42 (Friday, March 3, 2023)]
[Rules and Regulations]
[Pages 13299-13301]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-04424]



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 Rules and Regulations
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  Federal Register / Vol. 88 , No. 42 / Friday, March 3, 2023 / Rules 
and Regulations  

[[Page 13299]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2022-0532; Special Conditions No. 25-835-SC]


Special Conditions: Airbus SAS A320-200 Series Model A320-251N, -
252N, -253N, -271N, -272N, -273N Airplanes and A321-200 Series Model 
A321-251NX, -252NX, -253NX, -271NX, -272NX Airplanes; Flight Attendant 
Seat Mounted on Movable Interior Structure

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Airbus SAS 
(Airbus) A320-200 Series Model -251N, -252N, -253N, -271N, -272N, -273N 
(known as A320neo) airplanes and A321-200 Series Model -251NX, -252NX, 
-253NX, -271NX, -272NX (known as A321neo) airplanes. The airplanes 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 flight attendant seats 
mounted on movable lavatory doors. 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 Airbus on April 3, 2023.

FOR FURTHER INFORMATION CONTACT: Shannon Lennon, Human Machine 
Interface, AIR-626, Technical Innovation Policy 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: 

Background

    On October 27, 2020, Airbus SAS applied for a change to Type 
Certificate No. A28NM for flight attendant seats mounted on movable 
lavatory doors in A320-200 Series Model A320-251N, -252N, -253N, -271N, 
-272N, and -273N (known as A320neo) airplanes and A321-200 Series Model 
A321-251NX, -252NX, -253NX, -271NX, and -272NX (known as A321neo) 
airplanes. These airplanes are twin-engine, transport category 
airplanes. The A320neo has a maximum passenger seating capacity of 179 
and the A321neo has a maximum passenger seating capacity of 244.
    The applicable airworthiness requirements do not contain adequate 
or appropriate safety standards for this new lavatory door-mounted 
flight attendant seat. Section 25.785 of title 14, Code of Federal 
Regulations (14 CFR) specifies certain requirements for flight 
attendant seats but did not consider flight attendant seats mounted on 
movable structure such as lavatory doors and, therefore, does not 
specifically address additional concerns associated with ensuring the 
flight attendant seats are safe to occupy when necessary. Therefore, 
special conditions are necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR) 21.101, Airbus must show that the A320neo and A321neo airplanes, 
as changed, continue to meet the applicable provisions of the 
regulations listed in Type Certificate No. A28NM 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 Airbus A320neo and A321neo 
airplanes 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, 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 Airbus A320neo and A321neo airplanes 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 Airbus A320neo and A321neo airplanes will incorporate the 
following novel or unusual design features:
    Flight attendant seats mounted on movable lavatory doors.

Discussion

    Airbus will install, in A320neo and A321neo airplanes, flight 
attendant seats on lavatory doors. The lavatory door-mounted flight 
attendant seat is intended to be occupied during all phases of flight, 
including takeoff and landing.
    Flight attendant seats are typically floor-mounted or wall-mounted 
on a non-movable structure (e.g., mounted on monument walls) which is 
attached to the airplane structure. The installation of a flight 
attendant seat on movable structure, such as a lavatory door, 
introduces certain issues that must be addressed to ensure safety of 
the attendant seat occupant. Such considerations include ensuring that 
the lavatory door is closed (fixed) when the flight attendant seat is 
to be occupied and ensuring that the lavatory door lock mechanism is 
reliable after frequent use of the lavatory door. Additionally, the 
lavatory door, door locking mechanism, and door housing will need to 
withstand certain loading conditions as that structure is part of the 
load path

[[Page 13300]]

between seat structure and airplane structure.
    Other issues include ensuring that the flight attendant seat is 
available to use when necessary, which requires a way to ensure the 
lavatory is not occupied when the flight attendant seat must be 
occupied. Also, additional maintenance requirements will need to be 
considered to establish the reliability of the lavatory door locking 
mechanism, as it is a feature that will be frequently used.
    The 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 of Comments

    The FAA issued Notice of Proposed Special Conditions No. 25-22-03-
SC for the Airbus A320-200 Series Model A320-251N, -252N, -253N, -271N, 
-272N, and -273N, and A321-200 Series Model A321-251NX, -252NX, -253NX, 
-271NX, and -272NX airplanes, which was published in the Federal 
Register on October 17, 2022 (87 FR 62739). The FAA received responses 
from two commenters--Air Line Pilots Association, International (ALPA); 
and The Boeing Company (Boeing). ALPA provided a general comment that 
they support the special conditions. Boeing provided four comments 
summarized as follows:
    Comment Summary 1: Boeing suggested a revision of the text of 
proposed special condition (a) for purposes of identifying additional 
components of the flight attendant seat-system primary load path that 
must be shown to withstand the emergency landing dynamic loads 
including the lavatory door hinge and lavatory door-interfacing wall 
panels. Boeing states that the proposed special condition does not 
address the structural interface area surrounding the lavatory door 
attachment to the lavatory housing and that its suggested revision is 
consistent with guidance provided in section 9.c.(3)(b) of Advisory 
Circular 25.562-1B, ``Dynamic Evaluation of Seat Restraint Systems and 
Occupant Protection on Transport Airplanes,'' for similar 
installations. Boeing also suggested a revision of the text of proposed 
special condition (a) for purposes of clarifying that both the flight 
attendant seat installation and lavatory attachment to the airplanes' 
structure must meet the requirements of 14 CFR 25.561.
    FAA Response: No change to this special condition is necessary. The 
proposed special condition (a) was intended to describe the lavatory 
structure that must withstand the emergency landing dynamic loads 
prescribed in Sec.  25.562 vs. the lavatory structure that must meet 
the requirements of Sec.  25.561. It is not necessary for these special 
conditions to identify that the seat installation meet the requirements 
of Sec.  25.561 because that requirement already exists via Sec.  
25.785(b) and is therefore, outside the scope of these special 
conditions. It is also sufficient to identify that the lavatory door-
mounted flight attendant seat-system primary load path must meet the 
emergency landing dynamic loads without identifying all components of 
that load path because structural components such as the lavatory door, 
door hinge, and interfacing lavatory panels are readily recognized as 
part of the load path. The exception is the lavatory door locking 
mechanism. This is specifically emphasized in this special condition as 
it is a movable assembly that is expected to be frequently manipulated 
by the airplane occupants and, as such, a novel feature in the flight 
attendant seat load path.
    Comment Summary 2 and 3: Boeing recommended a revision to special 
condition (b)(1) that would require a design feature that clearly 
indicates positive engagement of all latches or mechanisms required to 
secure the lavatory door, including a placard describing the required 
steps to secure and verify engagement of the door. Boeing also 
recommends a revision to special condition (c) that would require a 
placard near the flight attendant seat that instructs the flight 
attendant to perform a visual inspection of the lavatory interior to 
ensure the lavatory is not occupied before engaging the door and 
occupying the attendant seat. Boeing states that a placard should be 
included to ensure that the lavatory is not occupied when use of the 
flight attendant seat is necessary.
    FAA Response: No changes to special conditions (b) or (c) are 
necessary. While the recommended design features may constitute an 
acceptable means of compliance, other means may be utilized that could 
also be acceptable. Therefore, it is not necessary or appropriate to 
require specific design features for these special conditions.
    Comment Summary 4: Boeing recommended a revision to special 
condition (e) to require that the lavatory door hinge mechanism, along 
with the locking mechanism, must meet the requirements of Sec.  25.561 
and other foreseeable operating conditions in order to show that these 
mechanisms are reliable within their expected life cycle. This 
recommendation includes requiring static testing beyond the life-cycle 
testing of the locking and hinge mechanisms to ensure adequate 
structural capability over the expected lifetime of the installation.
    FAA Response: Special condition (e) is intended to ensure that the 
movable parts of the lavatory door assembly remain reliable within the 
expected life cycle of the installation. The lavatory door locking 
mechanism is specifically identified as it will be routinely 
manipulated by aircraft occupants as they utilize the lavatory. 
However, the door hinge is also a movable part that is applicable to 
this special condition even though it does not get repositioned in 
service like the lavatory door lock. For this reason the FAA agrees 
with the recommendation to include the lavatory door hinge within the 
text of special condition (e). While the FAA agrees that the approach 
of conducting static testing of the lavatory door hinge and locking 
mechanisms beyond the life-cycle testing constitutes an acceptable 
means of compliance, other means may be utilized that could also be 
acceptable. Therefore, it is not necessary to require this specific 
compliance approach in the special condition. Proposed special 
condition (e) is revised as follows:
    The lavatory door locking and hinge mechanisms must be shown to 
withstand frequent use. Potential deterioration of moving parts must be 
addressed to show that the locking and hinge mechanisms are reliable 
within the established life cycle. Accordingly, instructions for 
continued airworthiness must also be defined for the locking and hinge 
mechanisms.
    All other special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Airbus A320 Series Model -251N, -252N, -253N, -271N, -272N, -273N 
(known as A320neo) and A321 Series Model -251NX, -252NX, -253NX, -
271NX, -272NX (known as A321neo) airplanes. Should Airbus 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 a certain novel or unusual design feature 
on A320 Series Model -251N, -252N, -253N, -271N, -272N, -273N (known as 
A320neo) and A321 Series Model -251NX, -252NX, -253NX, -271NX, -272NX 
(known as A321neo) airplanes. It is not a rule of general 
applicability.

[[Page 13301]]

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 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Airbus A320 Series Model -251N, -
252N, -253N, -271N, -272N, -273N (known as A320neo) and A321 Series 
Model -251NX, -252NX, -253NX, -271NX, -272NX (known as A321neo).
    (a) The lavatory door-mounted flight attendant seat-system primary 
load path, including the flight attendant seat, seat attachment means, 
the lavatory door, and lavatory door attachment to the lavatory 
housing--including the locking mechanism--must be shown to be capable 
of withstanding the emergency landing dynamic loads in accordance with 
Sec.  25.562. The lavatory housing and the lavatory attachment to the 
airplane structure must comply with the requirements of Sec.  25.561.
    (b) Means must be provided to ensure that the flight attendant seat 
can only be used if the lavatory door is securely locked in the closed 
position.
    (1) The procedures for establishing that the lavatory door is 
closed and locked prior to use of the flight attendant seat must become 
part of the cabin crew training.
    (2) The effects of structural deformation of the lavatory door and 
lavatory door housing must be addressed to prevent unlocking or failure 
of the locking mechanism.
    (c) Means must be provided to ensure that the lavatory is not 
occupied so that the flight attendant seat is available when necessary.
    (d) Means must be provided to ensure that no one is inadvertently 
trapped inside the lavatory when the lavatory door is locked to 
facilitate use of the flight attendant seat.
    (e) The lavatory door locking and hinge mechanisms must be shown to 
withstand frequent use. Potential deterioration of moving parts must be 
addressed to show that the locking and hinge mechanisms are reliable 
within their established life cycles. Accordingly, instructions for 
continued airworthiness must also be defined for the locking and hinge 
mechanisms.

    Issued in Kansas City, Missouri, on February 28, 2023.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2023-04424 Filed 3-2-23; 8:45 am]
BILLING CODE 4910-13-P


