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[Federal Register Volume 89, Number 224 (Wednesday, November 20, 2024)]
[Rules and Regulations]
[Pages 91539-91541]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-27041]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. FAA-2024-2164; Special Conditions No. 33-025-SC]

Special Conditions: Pratt and Whitney Canada Model PW220A Engine; 
30-Minute All Engine Operating Power Rating

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 Pratt and Whitney 
Canada (P&WC) Model PW220A engine. This engine will have a novel or 
unusual design feature when compared to the state of technology 
envisioned in the airworthiness standards for aircraft engines. This 
design feature is a 30-minute all engine operating (AEO) power rating. 
This rating will be used for hovering at increased power for search and 
rescue missions. 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 P&WC on November 20, 2024. Send 
comments on or before January 6, 2025.

ADDRESSES: Send comments identified by Docket No. FAA-2024-2164 using 
any of the following methods:
     Federal eRegulations Portal: Go to 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.
    Docket: Background documents or comments received may be read at 
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: Alberto Hernandez, Engine and 
Propulsion Section, AIR-625, Technical Policy Branch, Policy and 
Standards Division, Aircraft Certification Service, Federal Aviation 
Administration, 107 Charles W. Grant Parkway, Atlanta, GA 30354; 
telephone (781) 238-7329; 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 finds, pursuant to title 14, Code of Federal 
Regulations (14 CFR) 11.38(b), that new comments are unlikely, and 
notice and comment prior to this publication are unnecessary.

Privacy

    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in Sec.  
11.35, the FAA will post all comments received without change to 
www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact received about these special conditions.

Confidential Business Information

    Confidential Business Information (CBI) is commercial or financial 
information that is both customarily and actually treated as private by 
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), 
CBI is exempt from public disclosure. If your comments responsive to 
these special conditions contain commercial or financial information 
that is customarily treated as private, that you actually treat as 
private, and that is relevant or responsive to these special 
conditions, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and the indicated comments will not be 
placed in the public docket of these special conditions. Send 
submissions containing CBI to the individual listed in the For Further 
Information Contact section above. Comments the FAA receives, which are 
not specifically designated as CBI, will be placed in the

[[Page 91540]]

public docket for these special conditions.

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 November 16, 2021, P&WC applied for a type certificate for its 
new Model PW220A engine. The Model PW220A engine is a new centerline 
free-turbine turboshaft engine design intended to be used on transport 
category twin-engine helicopters. The engine architecture is a split 
compression system that incorporates the latest generation design 
methodology of a high-pressure ratio compressor, providing significant 
improvements in specific fuel consumption (SFC) and power.
    A single low pressure compressor (LPC) is driven by a two-stage 
uncooled power turbine, which also provides mechanical power through an 
output shaft to the helicopter rotor system. The high pressure 
compressor (HPC) is a two-stage compressor system driven by a single-
stage cooled high pressure turbine (HPT).

Type Certification Basis

    Under the provisions of 14 CFR 21.17, P&WC must show that the Model 
PW220A engine meets the applicable provisions of part 33, dated 
February 1, 1965, as amended by amendments 33-1 through 33-34.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 33) do not contain adequate or 
appropriate safety standards for the P&WC Model PW220A engine 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, these special conditions would also apply to 
the other model under Sec.  21.101.
    The FAA issues special conditions, as defined in Sec.  11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Feature

    The P&WC Model PW220A engine will incorporate the following novel 
or unusual design feature:
    A 30-minute all engine operating (AEO) power rating.

Discussion

    The type certification basis for the Model PW220A engine does not 
contain adequate or appropriate airworthiness standards to address a 
30-minute AEO power rating. Therefore, special conditions are necessary 
to provide additional requirements for rating definition, instructions 
for continued airworthiness (ICA), and endurance testing.
    The 30-minute time limit applies to each instance the rating is 
used; however, there is no limit to the number of times the rating can 
be used during any one flight, and there is no cumulative time 
limitation. The ICA requirement in these special conditions is intended 
to address the unknown nature of actual usage of the 30-minute AEO 
power rating and any associated engine deterioration. The applicant is 
expected to make an assessment of the expected usage and publish ICA's 
and airworthiness limitations section (ALS) limits in accordance with 
those assumptions, such that engine deterioration is not excessive. The 
endurance test requirement of 25 hours of operation at a 30-minute AEO 
rating is similar to several special conditions issued over the past 20 
years addressing the same subject. Because the PWC Model PW220A 
turboshaft engine has a continuous one engine inoperative (OEI) rating 
and limits equal to or higher than the 30-minute AEO rating, the test 
time performed at the continuous OEI rating may be credited toward the 
25-hour requirement. However, test time spent at other rating elements 
of the Sec.  33.87 endurance test, such as takeoff or other OEI ratings 
(that may be equal to or higher values), may not be counted toward the 
25 hours of required running. 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 
P&WC Model PW220A engine. Should PW&C 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 engine model. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 33

    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, and 
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 Pratt and Whitney Canada Model 
PW220A engine.
    In addition to the general definitions in 14 CFR 1.1, the following 
definition applies to these special conditions: ``Rated 30-Minute All 
Engine Operating (AEO) Power,'' means the approved shaft horsepower 
developed under static conditions at the specified altitude and 
temperature, and within the operating limitations established under 
part 33, and limited in use to periods not exceeding 30-minutes each.
    In addition to the airworthiness standards in part 33, the 
following special conditions apply:
    (a) Sections 33.1 Applicability and 33.3 General: As applicable, 
all documentation, testing, and analysis required to comply with the 
part 33 certification basis, must account for the 30-minute AEO rating, 
limits, and usage.
    (b) Section 33.4, Instructions for Continued Airworthiness (ICA). 
In addition to the requirements of Sec.  33.4, the ICA must:
    (1) Include instructions to ensure that in-service engine 
deterioration due to rated 30-minute AEO power usage will not be 
excessive, meaning that all other approved ratings are available within 
associated limits and assumed usage, for successive flights; and that 
deterioration will not exceed that assumed for declaring a time between 
overhaul (TBO) period.
    (i) The applicant must validate the adequacy of the maintenance 
actions required under paragraph (b)(1) above.

[[Page 91541]]

    (2) Include in the airworthiness limitations section (ALS), any 
mandatory inspections and serviceability limits related to the use of 
the 30-minute AEO rating.
    (c) Section 33.87, Endurance Test. In addition to the requirements 
of Sec. Sec.  33.87(a) and 33.87(d), the overall test run must include 
a minimum of 25 hours of operation at 30-minute AEO power and limits, 
divided into periods of 30-minutes AEO power with alternate periods at 
maximum continuous power or less.
    (1) Modification of the Sec.  33.87 test requirements to include 
the 25 hours of operation at 30-minute AEO power rating must be 
proposed by the Applicant and accepted by the FAA.
    (2) Each Sec.  33.87(d) continuous one-engine-inoperative (OEI) 
rating test period of 30-minutes or longer, run at power and limits 
equal to or higher than the 30-minutes AEO rating, may be credited 
toward this requirement. Note that the test time required for the 
takeoff or other OEI ratings may not be counted toward the 25 hours of 
operation required at the 30-minute AEO rating.

    Issued in Seattle, Washington, on November 13, 2024.
Paul R. Siegmund,
Acting Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2024-27041 Filed 11-19-24; 8:45 am]
BILLING CODE 4910-13-P
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