[Federal Register Volume 87, Number 167 (Tuesday, August 30, 2022)]
[Rules and Regulations]
[Pages 52854-52856]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-18722]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 29

[Docket No. FAA-2022-0183; Special Conditions No. 29-056-SC]


Special Conditions: The Boeing Company, Leonardo S.p.a. Model 
AW139 Helicopter; Use of New Hovering Out of Ground Effect Utility 
Power on the Model AW139 Helicopter

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Leonardo S.p.a. 
(Leonardo) Model AW139 helicopter. This helicopter as modified by The 
Boeing Company (Boeing) will have a novel or unusual design feature 
when compared to the state of technology envisioned in the 
airworthiness standards for helicopters. This design feature 
incorporates a 2.5-minute all engines operating (AEO) power restricted 
for use at helicopter operating speeds below 60 knots indicated 
airspeed (KIAS), and hovering out of ground effect (HOGE). This power 
is referred to as 2.5-minute HOGE utility power (HUP), or 2.5-minute 
HUP. The 2.5-minute HUP is greater than the transmission power 
limitations associated with takeoff and AEO. 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 September 29, 2022.

FOR FURTHER INFORMATION CONTACT: Dorina Mihail, Propulsion and Energy 
Section, AIR-624, Technical Innovation Policy Branch, Policy and 
Innovation Division, Aircraft Certification Service, Federal Aviation 
Administration, 1200 District Avenue, Burlington, MA 01803; telephone 
781-238-7153; fax 781-238-7199; email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    On September 18, 2020, Boeing applied for a supplemental type 
certificate for performance envelope expansion of the Leonardo Model 
AW139 helicopter. The AW139 helicopter as changed, is a medium twin-
engine 14 CFR part 29 transport category B helicopter with a 15,521 
pounds (7040 Kg) maximum takeoff weight and a maximum seating capacity 
of nine passengers and two crew. This helicopter takeoff and landing 
altitude is 10,000 feet density altitude (Hd), and the forward flight 
altitude is 11,000 feet Hd. This helicopter has the capability for 
Category II instrument landing system (ILS) approaches. The Model AW139 
helicopter as changed will be equipped with two PT6C-67C1 engines. The 
Model AW139 helicopter as changed will have a 2.5-minute HUP for use in 
HOGE that exceeds the transmission power limitations associated with 
takeoff and AEO.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Boeing must show that the 
Leonardo Model AW139 helicopter, as changed, continues to meet the 
applicable provisions of the regulations listed in Type Certificate No. 
R00002RD, or the applicable regulations in effect on the date of 
application for the change, except for earlier amendments as agreed 
upon by the FAA. The proposed certification basis for this supplemental 
type certificate is as follows:
    14 CFR 21.29 and Part 29, Amendment 29-1 through Amendment 29-45 
with 14 CFR 29.25, 29.143, 29.173, 29.175, 29.177 at Amendment 29-51, 
and 14 CFR 29.773 at Amendment 29-57.
    Equivalent Level of Safety Findings issued against:
    14 CFR 29.1305, as documented in the AB139 FAA Memo, dated December 
20, 2004.
    If the Administrator finds that the applicable airworthiness 
regulations (e.g., 14 CFR part 29) do not contain adequate or 
appropriate safety standards for the Leonardo Model AW139 helicopter 
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.
    In addition to the applicable airworthiness regulations and special 
conditions, the Leonardo Model AW139 helicopter must comply with the 
noise certification requirements of 14 CFR part 36.

[[Page 52855]]

    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 Feature

    The Leonardo Model AW139 helicopter will incorporate a novel or 
unusual design feature, which is a 2.5-minute AEO power that is greater 
than the transmission takeoff power limitations associated with takeoff 
and AEO. This power is restricted for use when HOGE and at helicopter 
operating speeds below 60 KIAS. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature.

Discussion

    The design feature will incorporate a 2.5-minute HUP that allows 
the pilot to enter HOGE, operate in HOGE, and depart from HOGE at high 
altitudes and ambient atmospheric temperatures. The use of the 2.5-
minute HUP is limited to periods of no longer than 2.5 minutes each 
use, under AEO conditions, at helicopter operating speeds below 60 KIAS 
and HOGE. Use of the 2.5-minute HUP is not part of, or combined with a 
takeoff operation.
    Helicopter operation at the 2.5-minute HUP will use the engine 
power higher than the rated maximum continuous power and limits but 
lower than the rated takeoff power and limits and does not exceed the 5 
minute takeoff rating for which the engines are type certificated. 
Existing part 33 regulations for the engines are adequate for the 
helicopter 2.5-minute HUP.
    Use of the 2.5-minute HUP exceeds the helicopter transmission power 
limitations associated with takeoff and AEO. Existing part 29 
regulations do not recognize helicopter operation that exceeds the 
transmission power limitations associated with takeoff and AEO. The 
special conditions that address the use of the 2.5-minute HUP on this 
model of helicopter, as modified by Boeing, are as follows.
    The Rotorcraft Flight Manual must specify that the use of the 2.5-
minute HUP is limited to periods no longer than 2.5 minutes each, under 
AEO conditions, at helicopter operating speeds below 60 KIAS and HOGE. 
Additionally, the Rotorcraft Flight Manual must specify that use of the 
2.5-minute HUP is not part of, or combined with, a takeoff operation.
    The requirement added to Sec.  29.49(c) provides for the 
development of helicopter performance data for 2.5-minute HUP 
utilization.
    The testing requirement added to Sec.  29.923(d) consists of two 
applications of 2.5-minute HUP torque and the maximum speed per 10-hour 
cycle. The 10-hour cycle represents a run of 10 hours in length that is 
repeated 20 times, for a total of (at least) 200 hours of endurance 
testing as required by Sec.  29.923(a). Therefore, the testing added to 
Sec.  29.923(d) provides for 40 applications of the 2.5-minute HUP 
during the 200-hour endurance test specified in Sec.  29.923(a). This 
testing is added to Sec.  29.923(d) ``Endurance tests; 90 percent of 
maximum continuous run,'' since the 2.5-minute HUP is not part of, or 
combined with, a takeoff operation, as stated in these special 
conditions and is expected to be used during mid-mission.
    The flight-test requirement added to Sec.  29.1049 is intended to 
address the hovering cooling provisions at the 2.5-minute HUP and HOGE 
following thermal stabilization at maximum weight, mission 
representative power, maximum altitude, and ambient temperatures 
specified in Sec.  29.1043(b). The flight-test continues with cycling 
in and out of the HUP mode, in a manner representative of the intended 
use of the 2.5-minute HUP, per the instructions specified in the 
Rotorcraft Flight Manual. The repeated successive HUP applications and 
time duration between HUP cycles result in the most critical condition 
for the cooling provisions required by Sec.  29.1041(a) and Sec.  
29.1041(b). The flight-test continues with departing the hover and 
transitioning to a maximum continuous power climb at the best rate of 
climb speed. Climb is continued for 5 minutes after the highest 
temperatures are observed or until the service ceiling is reached.
    The requirements added to Sec.  29.1305 are means for the pilot to 
identify when the 2.5-minute HUP level is achieved, when the event 
begins, and when the time interval expires. These means will assist the 
pilot in managing the 2.5-minute HUP short time duration in a pilot 
high-workload environment.
    The requirements added to Sec.  29.1521 are similar to the 
powerplant limitations for takeoff operations in Sec.  29.1521(b), 
modified to reflect the 2.5-minute HUP.
    The requirement added to Sec.  29.1587(b)(8) will require 
publishing the performance data developed under paragraph (b) of these 
special conditions in the Rotorcraft Flight Manual. These data must be 
clearly referenced to the appropriate hover charts and specify that 
they are not to be used for take-off or landing determinations.
    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.

Discussion of Comments

    The FAA issued Notice of Proposed Special Conditions No. 29-22-01-
SC for the Leonardo Model AW139 helicopter, which was published in the 
Federal Register on May 3, 2022 (87 FR 26143). The FAA did not receive 
any comments.

Applicability

    As discussed above, these special conditions are applicable to the 
Leonardo Model AW139 helicopter. Should Boeing apply at a later date 
for a supplemental type certificate to modify any other model included 
on Type Certificate No. R00002RD, 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 the Leonardo Model AW139 helicopter. It is not a rule of general 
applicability and affects only the applicant who applied to the FAA for 
approval of this feature on the helicopter.

List of Subjects in 14 CFR Part 29

    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 Leonardo S.p.a. Model AW139 
helicopter, as modified by The Boeing Company.
    (a) The Rotorcraft Flight Manual must state the following:
    (1) Use of the 2.5-minute Hovering Out of Ground Effect (HOGE) 
Utility Power (2.5-minute HUP) is limited to a period no longer than 
2.5 minutes each, under all engine operating (AEO) conditions, at 
helicopter operating speeds below 60 knots indicated airspeed (KIAS) 
and HOGE.
    (2) Use of the 2.5-minute HUP is not part of, or combined with, a 
takeoff operation.
    (b) In addition to the requirements of Sec.  29.49(c), the out-of-
ground effect hover performance must be determined over

[[Page 52856]]

the ranges of weight, altitude, and temperatures for which 
certification is requested with the 2.5-minute HUP.
    (c) In addition to the requirements of Sec.  29.923(d) when 
performing the endurance test, the 2.5 minute all engines operating 
must be performed using two applications of 2.5-minute HUP torque and 
the maximum speed for use with 2.5-minute HUP torque, per 10-hour 
cycle.
    (d) In addition to the requirements of Sec.  29.1049, the hovering 
cooling provisions at the 2.5-minute HUP must be shown as follows--
    (1) Conduct a thermal stabilization at maximum weight, mission 
representative power, maximum altitude, and ambient temperatures 
specified in Sec.  29.1043(b); following stabilization, increase power 
to the 2.5-minute HUP and HOGE for a duration of 2.5 minutes (150 
seconds).
    (2) Cycle in and out the HUP mode in a manner representative of the 
intended use of the 2.5-minute HUP, and per the instructions specified 
in the Rotorcraft Flight Manual, if any. The HUP cycles should account 
for repeated successive HUP applications and time duration between HUP 
cycles resulting in the most critical condition for the cooling 
provisions required by Sec.  29.1041(a) and Sec.  29.1041(b).
    (3) Following the tests in paragraphs (d)(1) and (d)(2) of these 
special conditions, depart the hover and transition to a maximum 
continuous power climb at the best rate of climb speed. Continue the 
climb until 5 minutes after the highest temperatures are observed or 
until the service ceiling is reached.
    (e) In addition to the requirements of Sec.  29.1305, the pilot 
must have the means to identify the 2.5-minute HUP time limit 
associated with its use as follows--
    (1) When the power level is achieved,
    (2) when the event begins, and
    (3) when the time interval expires.
    These indications must be clear and unambiguous to the pilot and 
must not cause pilot confusion. The use of these indications must be 
evaluated in operationally relevant scenarios in accordance with Sec.  
29.1523 for crew workload.
    (f) In addition to the requirements of Sec.  29.1521, the use of 
the 2.5-minute HUP must be limited by the following:
    (1) The maximum rotational speed, which may not be greater than--
    (i) The maximum value determined by the rotor design; or
    (ii) The maximum value demonstrated during the type tests;
    (2) The maximum allowable turbine inlet or turbine outlet gas 
temperature (for turbine engines);
    (3) The maximum allowable power or torque for each engine, 
considering the power input limitations of the transmission with all 
engines operating;
    (4) The maximum allowable power or torque for each engine 
considering the power input limitations of the transmission with one 
engine inoperative;
    (5) The time limit for the use of the power corresponding to the 
limitations established in paragraphs (f)(1) through (f)(4) of these 
special conditions; and
    (6) The maximum allowable engine and transmission oil temperatures, 
if the time limit established in paragraph (f)(5) of these special 
conditions exceeds 2 minutes.
    (7) Use of 2.5-minute HUP is limited to HOGE only.
    (g) In addition to the requirements of Sec.  29.1587(b)(8), the 
Rotorcraft Flight Manual must contain the out-of-ground effect hover 
performance determined under paragraph (b) of these special conditions, 
and the maximum safe wind demonstrated under the ambient conditions for 
the data presented. In addition, the Rotorcraft Flight Manual must 
include the maximum weight for each altitude and temperature condition 
at which the rotorcraft can safely hover out-of-ground-effect in winds 
not less than 17 knots from all azimuths. These data must be clearly 
referenced to the appropriate hover charts and specify that they are 
not to be used for take-off or landing determinations.

    Issued in Kansas City, Missouri, on August 25, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation 
Division, Aircraft Certification Service.
[FR Doc. 2022-18722 Filed 8-29-22; 8:45 am]
BILLING CODE 4910-13-P


