Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Rules and Regulations 73219 

TABLE 13—TEST OPERATING CONDITIONS FOR VARIABLE- OR MULTIPLE-CAPACITY LOW-TEMPERATURE OUTDOOR

DEDICATED CONDENSING UNITS—Continued 

Test title 

Suction 

dew point, 

°F 

Return gas, 

°F 

Condenser 

air entering 

dry-bulb, 

°F 

Condenser 

air entering 

wet-bulb, 

°F 1

Compressor operating mode 

Off-Cycle, Condition C ...................... ........................ ........................ 35 34 Compressor Off. 

Notes: 

1 Required only for evaporative condensing units (e.g., incorporates a slinger ring). 

TABLE 14—TEST OPERATING CONDITIONS FOR VARIABLE- OR MULTIPLE-CAPACITY LOW-TEMPERATURE INDOOR

DEDICATED CONDENSING UNITS

Test title 

Suction 

dew point, 

°F 

Return gas, 

°F 

Condenser 

air entering 

dry-bulb, 

°F 

Condenser 

air entering 

wet-bulb, 

°F 1

Compressor operating mode 

Capacity, Condition A, Minimum Capacity.¥22 5 90 75 Minimum Capacity, k=1. 

Capacity, Condition A, Intermediate 

Capacity.

¥22 5 90 75 Intermediate Capacity, k=i. 

Capacity, Condition A, Maximum Capacity.¥22 5 90 75 Maximum Capacity, k=2. 

Off-Cycle, Condition A ...................... ........................ ........................ 90 75 Compressor Off. 

Notes: 

1 Required only for evaporative condensing units (e.g., incorporates a slinger ring). 

* * * * * 

[FR Doc. 2023–18531 Filed 10–24–23; 8:45 am] 

BILLING CODE 6450–01–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2022–1740; Special 

Conditions No. 25–841–SC] 

Special Conditions: The Boeing 

Company Model 777 Series Airplanes; 

Passenger Seats With Pretensioner 

Restraint Systems 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for The Boeing Company 

(Boeing) Model 777 series airplanes. 

These 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 pretensioner restraint systems 

installed on passenger seats. 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: Effective November 24, 2023. 

FOR FURTHER INFORMATION CONTACT: 

Shannon Lennon, Cabin Safety, AIR– 

624, Technical Policy Branch, Policy 

and Standards Division, Aircraft 

Certification Service, Federal Aviation 

Administration, 2200 South 216th 

Street, Des Moines, Washington 98198; 

telephone and fax 206–231–3209; email 

shannon.lennon@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

On September 30, 2021, Boeing 

applied for an amendment to Type 

Certificate No. T00001SE for Boeing 

Model 777 series airplanes. These 

airplanes, currently approved under 

Type Certificate No. T00001SE, are 

twin-engine, transport-category 

airplanes with maximum seating for 495 

passengers and a maximum takeoff 

weight of 775,000 pounds. 

Type Certification Basis 

Under the provisions of 14 CFR 

21.101, Boeing must show that Model 

777 series airplanes meet the applicable 

provisions of the regulations listed in 

Type Certificate No. T00001SE, 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 Boeing Model 777 series 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, 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 § 21.101. 

In addition to the applicable 

airworthiness regulations and special 

conditions, Boeing Model 777 series 

airplanes must comply with the fuelvent and exhaust-emission requirements 

of 14 CFR part 34, and the noisecertification requirements of 14 CFR 

part 36. 

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 

§ 21.101. 

Novel or Unusual Design Features 

Boeing Model 777 series airplanes 

will incorporate the following novel or 

unusual design feature: 

Forward-facing seats incorporating a 

shoulder harness with pretensioner 


lotter on DSK11XQN23PROD with RULES1
73220 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Rules and Regulations 

device, otherwise known as a 

pretensioner restraint system, which is 

intended to protect the occupants from 

head injuries. 

Discussion 

Boeing will install, in Model 777 

series airplanes, forward-facing seats 

that incorporate a shoulder harness with 

a pretensioner system, for head-injury 

protection, at each seat place. 

Shoulder harnesses have been widely 

used on flight-attendant seats, flightdeck seats, in business jets, and in 

general-aviation airplanes to reduce 

occupant head injury in the event of an 

emergency landing. Special conditions, 

pertinent regulations, and published 

guidance relate to other restraint 

systems. However, the use of 

pretensioners in the restraint system on 

transport-airplane seats is a novel 

design. 

The pretensioner restraint system 

utilizes a retractor that eliminates slack 

in the shoulder harness and pulls the 

occupant back into the seat prior to 

impact. This has the effect of reducing 

forward translation of the occupant, 

reducing head arc, and reducing loads 

in the shoulder harness. 

Pretensioner technology involves a 

step-change in loading experienced by 

the occupant for impacts below and 

above that at which the device deploys, 

because activation of the shoulder 

harness, at the point at which the 

pretensioner engages, interrupts uppertorso excursion. Such excursion could 

result in the head-injury criteria (HIC) 

being higher at an intermediate impact 

condition than that resulting from the 

maximum impact condition 

corresponding to the test conditions 

specified in § 25.562. See condition 1 in 

these special conditions. 

The ideal triangular maximumseverity pulse is defined in Advisory 

Circular (AC) 25.562–1B, ‘‘Dynamic 

Evaluation of Seat Restraint Systems 

and Occupant Protection on Transport 

Airplanes.’’ For the evaluation and 

testing of less-severe pulses for purposes 

of assessing the effectiveness of the 

pretensioner setting, a similar triangular 

pulse should be used with acceleration, 

rise time, and velocity change scaled 

accordingly. The magnitude of the 

required pulse should not deviate below 

the ideal pulse by more than 0.5g until 

1.33 t1 is reached, where t1 represents 

the time interval between 0 and t1 on 

the referenced pulse shape, as shown in 

AC 25.562–1B. This is an acceptable 

method of compliance to the test 

requirements of the special conditions. 

Additionally, the pretensioner might 

not provide protection, after actuation, 

during secondary impacts. Therefore, 

the case where a small impact is 

followed by a large impact should be 

addressed. If the minimum deceleration 

severity at which the pretensioner is set 

to deploy is unnecessarily low, the 

protection offered by the pretensioner 

may be lost by the time a second, larger 

impact occurs. 

Conditions 1 through 4 ensure that 

the pretensioner system activates when 

intended, to provide the necessary 

protection of occupants. This includes 

protection of a range of occupants under 

various accident conditions. Conditions 

5 through 10 address maintenance and 

reliability of the pretensioner system, 

including any outside influences on the 

mechanism, to ensure it functions as 

intended. 

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. 25–23–01–SC 

for Boeing Model 777 airplanes, which 

was published in the Federal Register 

on May 11, 2023 (88 FR 30262). 

The FAA received one response, from 

the Air Line Pilots Association, 

International, in support of the special 

conditions. The special conditions are 

adopted as proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to Boeing 

Model 777 series airplanes. 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 a certain 

novel or unusual design feature on one 

model series of airplanes. It is not a rule 

of general applicability. 

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 Boeing Model 777 series 

airplanes. 

In addition to the requirements of 

§ 25.562, forward-facing passenger seats 

with pretensioner restraint systems 

must meet the following: 

(1) Head Injury Criteria (HIC) 

The HIC value must not exceed 1000 

at any condition at which the 

pretensioner does or does not deploy, 

up to the maximum severity pulse that 

corresponds to the test conditions 

specified in § 25.562. Tests must be 

performed to demonstrate this, taking 

into account any necessary tolerances 

for deployment. 

When an airbag device is present in 

addition to the pretensioner restraint 

system, and the anthropomorphic test 

device (ATD) has no apparent contact 

with the seat/structure but has contact 

with an airbag, a HIC unlimited score in 

excess of 1000 is acceptable, provided 

the HIC15 score (calculated in 

accordance with 49 CFR 571.208) for 

that contact is less than 700. 

ATD head contact with the seat or 

other structure, through the airbag, or 

contact subsequent to contact with the 

airbag, requires a HIC value that does 

not exceed 1000. 

(2) Protection During Secondary 

Impacts 

The pretensioner activation setting 

must be demonstrated to maximize the 

probability of the protection being 

available when needed, considering 

secondary impacts. 

(3) Protection of Occupants Other Than 

50th Percentile 

Protection of occupants for a range of 

stature from a 2-year-old child to a 95th 

percentile male must be shown. For 

shoulder harnesses that include 

pretensioners, protection of occupants 

other than a 50th percentile male may 

be shown by test or analysis. In 

addition, the pretensioner must not 

introduce a hazard to passengers due to 

the following seating configurations: 

(a) The seat occupant is holding an 

infant. 

(b) The seat occupant is a child in a 

child-restraint device. 

(c) The seat occupant is a pregnant 

woman. 

(4) Occupants Adopting the Brace 

Position 

Occupants in the traditional brace 

position when the pretensioner activates 

must not experience adverse effects 

from the pretensioner activation. 


lotter on DSK11XQN23PROD with RULES1
Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Rules and Regulations 73221 

1The Commission voted 4–0 to approve this rule. 

(5) Inadvertent Pretensioner Actuation 

(a) The probability of inadvertent 

pretensioner actuation must be shown 

to be extremely remote (i.e., average 

probability per flight hour of less than 

10¥7. 

(b) The system must be shown not to 

be susceptible to inadvertent 

pretensioner actuation as a result of 

wear and tear, nor inertia loads resulting 

from in-flight or ground maneuvers 

likely to be experienced in service. 

(c) The seated occupant must not be 

seriously injured as a result of 

inadvertent pretensioner actuation. 

(d) Inadvertent pretensioner actuation 

must not cause a hazard to the airplane, 

nor cause serious injury to anyone who 

may be positioned close to the retractor 

or belt (e.g., seated in an adjacent seat 

or standing adjacent to the seat). 

(6) Availability of the Pretensioner 

Function Prior to Flight 

The design must provide means for a 

crewmember to verify the availability of 

the pretensioner function prior to each 

flight, or the probability of failure of the 

pretensioner function must be 

demonstrated to be extremely remote 

(i.e., average probability per flight hour 

of less than 10¥7) between inspection 

intervals. 

(7) Incorrect Seat Belt Orientation 

The system design must ensure that 

any incorrect orientation (twisting) of 

the seat belt does not compromise the 

pretensioner protection function. 

(8) Contamination Protection 

The pretensioner mechanisms and 

controls must be protected from external 

contamination associated with that 

which could occur on or around 

passenger seating. 

(9) Prevention of Hazards 

The pretensioner system must not 

induce a hazard to passengers in case of 

fire, nor create a fire hazard, if activated. 

(10) Functionality After Loss of Power 

The system must function properly 

after loss of normal airplane electrical 

power and after a transverse separation 

in the fuselage at the most critical 

location. A separation at the location of 

the system does not have to be 

considered. 

Issued in Kansas City, Missouri, on 

October 19, 2023. 

Patrick R. Mullen, 

Manager, Technical Policy Branch, Policy and 

Standards Division, Aircraft Certification 

Service. 

[FR Doc. 2023–23519 Filed 10–24–23; 8:45 am] 

BILLING CODE 4910–13–P 

CONSUMER PRODUCT SAFETY 

COMMISSION 

16 CFR Part 1610 

[Docket No. CPSC–2019–0008] 

Standard for the Flammability of 

Clothing Textiles 

AGENCY: Consumer Product Safety 

Commission. 

ACTION: Final rule. 

SUMMARY: The U.S. Consumer Product 

Safety Commission (Commission or 

CPSC) is amending the Standard for the 

Flammability of Clothing Textiles. The 

revisions clarify existing provisions, 

expand permissible equipment and 

materials for testing, and update 

equipment requirements that are 

outdated. The Commission issues this 

amendment under the authority of the 

Flammable Fabrics Act. 

DATES: This rule is effective on April 22, 

2024. The incorporation by reference of 

the publication listed in this rule is 

approved by the Director of the Federal 

Register as of April 22, 2024. 

FOR FURTHER INFORMATION CONTACT: Will 

Cusey, Small Business Ombudsman, 

U.S. Consumer Product Safety 

Commission, 4330 East-West Highway, 

Bethesda, MD 20814; telephone (301) 

504–7945 or (888) 531–9070; email: 

sbo@cpsc.gov. 

SUPPLEMENTARY INFORMATION: 

I. Background 

On September 14, 2022, the 

Commission published a notice of 

proposed rulemaking (NPR), proposing 

to amend the Standard for the 

Flammability of Clothing Textiles at 16 

CFR part 1610 (Standard). 87 FR 56289. 

The Standard was codified under the 

Flammable Fabrics Act (FFA; 15 U.S.C. 

1191–1204). The purpose of the FFA is 

to prohibit the importation, manufacture 

for sale, or sale in commerce of any 

fabric or article of wearing apparel that 

is ‘‘so highly flammable as to be 

dangerous when worn by individuals.’’ 

Public Law 83–88, 67 Stat. 111 (June 30, 

1953). The Standard accomplishes this 

by providing a national standard for 

testing and rating the flammability of 

textiles and textile products used for 

clothing. The Standard specifies test 

equipment, materials, and procedures 

for testing the flammability of clothing 

textiles and prohibits the use of highly 

flammable textiles in clothing. 

The amendments proposed in the 

NPR and adopted in this final rule 1 aim 

to clarify existing provisions in the 

Standard and update the specifications 

for materials and equipment that have 

become outdated. The amendments do 

not alter the testing or criteria in the 

Standard for determining the 

flammability of a fabric or whether it is 

permissible for use in clothing; rather, 

they facilitate accurate testing and 

classifications by clarifying existing 

requirements and updating material and 

equipment specifications to reflect 

currently available materials, 

equipment, and technologies. 

The amendments proposed in the 

NPR and adopted in this final rule 

address three areas of the Standard. 

First, they aim to clarify and streamline 

the provisions regarding test result 

codes (i.e., burn codes), which help 

determine the classification of a textile 

and whether it may be used for clothing. 

The amendments remove an 

unnecessary code and revise wording in 

the provisions to clarify the existing 

requirements. Second, the amendments 

revise the stop thread specification, 

which indicates the thread that must be 

used in flammability testing. The 

description has become unclear, as 

threads matching the description in the 

Standard are no longer readily available. 

Third, amendments revise the 

refurbishing requirements in the 

Standard, which address dry cleaning 

and laundering specimens during the 

testing process. In recent years, there 

have been increasing restrictions on the 

use of the dry cleaning solvent specified 

in the Standard, and washing machines 

that meet the specifications required in 

the Standard are no longer made. 

The NPR and CPSC staff’s briefing 

package supporting it included detailed 

information about the need for the 

amendments, the rationale for the 

revisions, and test results illustrating 

the comparability of the flammability 

classifications under the existing 

Standard and amendments. The NPR 

also included detailed information 

about 16 CFR 1610.40 of the Standard, 

which permits the use of alternative 

apparatus, procedures, or criteria for 

tests for guaranty purposes. This 

allowance permits the continued use of 

the dry cleaning solvent and laundering 

methods in the current Standard by 

relying on CPSC’s test results 

demonstrating the comparability of test 

results under the current Standard and 

the amendments. 

This final rule adopts the 

amendments proposed in the NPR, with 

only minor modifications. Therefore, 

this notice focuses on comments 

received in response to the NPR and the 

minor modifications in the final rule. 

For detailed information about the 

amendments, the rationale for them, the 


lotter on DSK11XQN23PROD with RULES1