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Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations 412600001 or an engine fire shutoff switch having P/N 417000101 or P/N
417000102.
Request To Revise Parts Installation Prohibition Paragraph or Extend Compliance Time American Airlines, All Nippon Airways ANA, and United Airlines asked that the FAA revise paragraph n of the proposed AD to continue to allow, for a limited time, the installation of the engine fire handle with the part numbers on which an unsafe condition has been identified after the effective date of the AD. American Airlines and United Airlines asked that installing the parts be allowed for 15 months after the effective date of the AD, which is consistent with the referenced service information. ANA asked that it be allowed to install the parts until the engine fire handle with new part numbers is installed in accordance with paragraph i of the proposed AD. ANA
also asked that the compliance time specified in paragraph i of the proposed AD be extended to 24 months after the effective date of the AD.
American Airlines stated that this change is necessary because the repetitive inspections of the engine fire handle with the part numbers on which an unsafe condition has been identified remain in place until those part numbers are replaced by the new part numbers. American Airlines added that they would need a full panel or two new switches if there were findings of failed fire handles because they cant mix old and new parts. American Airlines, ANA, and United Airlines expressed their concern regarding parts availability due to limited supply. ANA
stated that the supply of the engine fire handles with new part numbers is insufficient worldwide due to the Coronavirus Disease 2019 COVID19.
The FAA partially agrees with the commenters requests, based on the limited supply of new part numbers available due to extenuating circumstances. The FAA has received a number of reports of failed engine fire handles found during the repetitive inspections. The frequency of failures found in service, and the provisions of the Parts Installation Prohibition of paragraph n of the proposed AD, could have forced operators to install the new part numbers from a limited supply before reaching the compliance time in paragraph i of this AD. Furthermore, as American Airlines stated, the repetitive inspections required by 28AWLFIRE
remain in place until a fire handle with new part numbers is installed. The repetitive inspections do not eliminate the latent failure of the engine fire
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handle, but they will limit the number of flights the airplanes can operate with a failed engine fire handle. Since paragraph n of the proposed AD would have applied to all airplanes including those airplanes delivered with the engine fire control panel having the new part number required by paragraph i of this AD, and since it is necessary to prohibit the replacement of the new part number with the old part number for those airplanes that are not covered by paragraph i of this AD, the FAA has revised paragraph o of this AD
paragraph n of the proposed AD to include an exception for airplanes identified in Boeing Requirements Bulletin B78781205SB26000800 RB, Issue 001, dated March 10, 2020. For airplanes affected by paragraph i of this AD, once operators comply with the actions required by paragraph i of this AD by installing parts with new part numbers, operators must continue to maintain the airplane configuration compliant with the AD requirements.
For airplanes delivered with the fire control panel having the new part number, paragraph o of this AD
prohibits the replacement of the new part numbers with the old part numbers on which the unsafe condition was identified.
The FAA does not agree with ANAs request to revise the compliance time in paragraph i of this AD to 24 months.
Since the level of impact of parts supply may vary for each operator, we are unable to determine an appropriate change to the compliance time in paragraph i of this AD that will result in a minimal impact on safety and on operators ability to comply with the AD
requirements. Therefore, operators that encounter limited parts supply that could hinder the ability to meet the requirements of paragraph i of this AD
within the compliance time indicated should request an AMOC to extend this compliance time. If data are provided to show that the extended compliance time addresses the unsafe condition, operators may request approval of an AMOC under the provisions of paragraph p of this AD. The FAA has not changed this AD regarding this issue.
Request To Revise Airworthiness Limitation 28AWLFIRE
The Air Line Pilots Association, International ALPA asked that the FAA revise Airworthiness Limitation 28AWLFIRE to remove the language that allows the flightcrew to perform an operational check of the engine fire handle. ALPA stated that because the proposed AD retains the actions required by AD 20190203, the
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proposed AD also retains the allowance for the flightcrew to perform the engine fire handle operational check in a manner approved by the principal operations inspector in lieu of being performed by specifically trained maintenance personnel per the procedures in 28AWLFIRE. ALPA
previously highlighted concern with the flightcrew conducting the check required by AD 20190203, and reiterated that concern in comments on the NPRM. ALPA noted that without specific training to flightcrews, the opportunity exists for the operational check to be performed inaccurately.
ALPA concluded that to ensure that the check is effective until the terminating action is accomplished, consistent procedures should be followed and documented by appropriately trained maintenance personnel, as specified in the proposed AD.
The FAA does not agree with the commenters request. Airworthiness Limitation 28AWLFIRE includes an allowance for the flightcrew to perform an operational check of the engine fire handle since the inspection interval is relatively short and the inspection procedure is relatively straightforward.
Based on this allowance, operators can develop the procedures for the flightcrew to perform an operational check in a timely manner. Operators must ensure that the operational check required by 28AWLFIRE is accurately performed by the flightcrew in order for the procedures to be approved by the principal operations inspector. The FAA
has not changed this AD in this regard.
Conclusion The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD
with the changes described previously, and minor editorial changes. The FAA
has determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and Do not add any additional burden upon the public than was already proposed in the NPRM.
The FAA also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Boeing Requirements Bulletin B78781205
SB26000800 RB, Issue 001, dated March 10, 2020. The service information describes procedures for replacing the
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