Voglio sapere a riguardo di…

Federal Register / Vol. 86, No. 184 / Monday, September 27, 2021 / Rules and Regulations the special condition as a result of the comment.
Comment Summary: TCCA
recommended that Special Condition no. 29 apply the non-teardown requirement to those components that need additional testing in accordance with 33.53a, Engine system and component tests or 33.91a, Engine system and component tests. TCCA
commented that, as the special condition is currently worded, some might apply the requirement only to internal engine parts. TCCA also requested that the FAA modify the special condition to require some posttest assessments for non-torn down components. TCCA also asked that the FAA clarify the requirement that then the life limits for these components must be established based on the endurance and durability demonstrations. TCCA contended that, as this requirement is currently worded, magniX could interpret it to mean that all internal parts of the electric engine would not need to be examined, including Non-Destructive Testing NDT, especially if there is no overhaul.
FAA Response: Special Condition no.
27 ensures that magniX addresses electric engine components that cannot be torn down for inspection. If the condition of these parts is questionable, then the requirements in Special Condition nos. 32b and 32b4 can be applied for additional data to substantiate the life limit. These special conditions address TCCAs comments.
The FAA did not change the special condition as a result of this comment.

lotter on DSK11XQN23PROD with RULES3

Special Condition No. 30, Containment The FAA proposed that Special Condition no. 30 would require the engine to provide containment features that protect against likely hazards from rotating components, unless magniX can show, by test or validated analysis, that the margin to rotor burst does not justify the need for containment features. The intent of this special condition is to prevent hazardous engine effects from structural failure of rotating components and the rotating parts that are built into them.
Comment Summary: Textron stated that the wording in Special Condition no. 30a relating to the required burst margin for the rotor is vague. Textron suggested that the FAA incorporate the following change to Special Condition no. 30a: The design of the case surrounding rotating components must provide for the containment of the rotating components in the event of failure unless the applicant shows that the margin to rotor burst
VerDate Sep<11>2014

19:16 Sep 24, 2021

Jkt 253001

unconditionally rules out the possibility of a rotor burst.
FAA Response: The FAA agrees with the proposed change and has modified Special Condition no. 30a to incorporate Textrons suggestion.
Comment Summary: Airbus stated that experience with electrical generators has shown that axial ejection of debris might induce severe damage to surroundings. Airbus stated that an axial containment demonstration is feasible for electric engines and generators, and therefore should be required by the FAA. Airbus said that this special condition should require magniX to show full containment capability, eliminating the need to identify forwardand aft-ejected debris in the engine installation manual.
Airbus recommended that the FAA
modify Special Condition no. 30a to state, The design of the engine must provide for axial and radial containment of the rotating components . . . Airbus also recommended the FAA modify Special Condition no. 30b to state, If the margin to burst shows the case must have containment features in the event of failure, the case must provide axial and radial containment of the failed rotating components.
FAA Response: These special conditions apply only to the magniX
engine designs. Special Condition no.
30b is similar to 33.94a, Blade containment and rotor unbalance tests, and 33.19a, Durability, except this special condition includes the engine rotors. This special condition allows magniX to approach containment like turbine engines or provide full containment, as suggested in the comment. If a magniX engine design cannot contain the rotors, life limits will be applied in accordance with Special Condition no. 13 Critical and lifelimited parts. Therefore the FAA did not change this special condition as a result of this comment.
Comment Summary: EASA stated that the intent of the proposed Special Condition no. 30b is not clear, since that paragraph requests the case to provide containment of the failed rotating component while requesting that the applicant define the energy level, the trajectory, and the size of the released fragments. EASA asked the FAA to rewrite Special Condition no.
30b to be differentiated from Special Condition no. 30a. EASA commented that Special Condition no. 30b should be dedicated to those cases where containment is not ensured.
FAA Response: Special Condition no.
30b provides a level of protection similar to that provided by FAA
regulations that manage turbine engine
PO 00000

Frm 00023

Fmt 4701

Sfmt 4700

53529

blade failures, except it includes the engine rotors. It precludes the release of high-energy debris radially outward of the rotors. If the magniX engines qualify for the provisions in Special Condition no. 30b, fragments resulting from rotor damage, and that travel forward or aft of the containment plane, must have their energy levels and trajectories defined.
The magniX engine configuration and declared containment capabilities would determine if compliance with Special Condition no. 30b is required.
The FAA made no change to this special condition as a result of this comment.
Special Condition No. 31, Operation With a Variable Pitch Propeller The FAA proposed that Special Condition no. 31 would require magniX
to conduct functional demonstrations, including feathering, negative torque, negative thrust, and reverse thrust operations, as applicable, based on the propeller or fans variable pitch functions that are planned for use on these electric engines, with a representative propeller. Also, since these electric engines may be installed with a variable pitch propeller, the special condition associated with the operation with a variable pitch propeller or fan is necessary.
Comment Summary: TCCA
commented that, in addition to the propeller control, there is a risk that an electric engine controller could fail and result in reverse engine rotation. TCCA
suggested that the FAA add a special condition that considers and minimizes the potential for engine controller failures that could result in reverse engine rotation.
FAA Response: The FAA does not agree with the comment. Section 33.75g2 provides a list of hazardous engine effects. The list includes thrust in the opposite direction. Special Condition no. 17d2 defines hazardous engine effects as those in 33.75g2, with several additions specifically applicable to these electric engines. These special conditions address the failure described in the comment.
Comment Summary: TCCA
recommended revising the Special Condition no. 31 text to read, . . . with a representative propeller or fan. These demonstrations may be conducted in a manner acceptable to the Administrator as part . . ..
FAA Response: The FAA has modified final Special Condition no. 31
to allow the Administrator to determine if a test is acceptable.

E:FRFM27SER3.SGM

27SER3