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Federal Register / Vol. 86, No. 34 / Tuesday, February 23, 2021 / Rules and Regulations www.regulations.gov by searching for and locating Docket No. FAA2020
0467; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M30, West Building Ground Floor, Room W12140, 1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Eric Igama, Aerospace Engineer, Systems and Equipment Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 907124137;
phone: 5626275388; fax: 562627
5210; email: roderick.igama@faa.gov.
SUPPLEMENTARY INFORMATION:
Discussion The FAA issued a notice of proposed rulemaking NPRM to amend 14 CFR
part 39 by adding an AD that would apply to all The Boeing Company Model 717200 airplanes. The NPRM
published in the Federal Register on June 19, 2020 85 FR 37031. The NPRM
was prompted by a report that during takeoff, both the captains and first officers airspeed indications froze at 80
knots. The NPRM proposed to require modifying the ADH system to display the proper airspeed indications, testing, and any applicable corrective actions.
The FAA is issuing this AD to address pitot tubes blocked by ice, which could affect the airspeed indication provided to the flightcrew through the ADH
system and result in loss of aircraft controllability.
Comments The FAA gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM
and the FAAs response to each comment.
Support for the NPRM
Three commenters, The Air Line Pilots Association, International ALPA, Boeing, and Patrick Imperatrice, indicated support for the NPRM.
Request To Withdraw the NPRM
Hawaiian Airlines stated that existing crew procedures would produce the
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same result as the actions specified in the proposed AD and asserted that the proposed actions should remain optional. The commenter explained that with these existing crew procedures, operators should not be subjected to the requirements specified in the proposed AD. The commenter asserted that operators with strong crew cultures, processes, and procedures would mitigate the unsafe condition addressed by the NPRM without unnecessary and costly modification to the airplane. The commenter provided text from its existing crew procedures with recommended changes and asked that these procedures be considered as alternatives to the actions described in Boeing Alert Service Bulletin 717
30A0009, dated March 31, 2020 which was identified as the appropriate source of service information for completing the actions specified in the NPRM. The FAA infers that the commenter is requesting that the NPRM be withdrawn.
The FAA disagrees with the commenters request. The FAA has determined that the crew procedures identified by the commenter do not adequately address the unsafe condition associated with the ADH system. The FAAs determination was based on a report from Boeing that three operators reported that the ADH is not operating correctly. The FAA notes that this AD
requires modifying the ADH system to display the proper airspeed indications and testing to address the unsafe condition, while the commenters proposal involves only procedural changes in lieu of a modification.
However, operators may apply for an alternative method of compliance AMOC under the provisions of paragraph i of this AD, provided they can show that their proposed crew/
operational procedures would adequately address the unsafe condition. The FAA has determined that it is necessary to proceed with issuing the final rule as proposed and has not changed this AD regarding this issue.
Conclusion The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed, except for minor editorial changes. The FAA has determined that these minor changes:

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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.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Boeing Alert Service Bulletin 71730A0009, dated March 31, 2020. This service information describes procedures for modifying the ADH system by installing new wires between the station STA
110 relay panel and the left radio rack, and doing tests and applicable corrective actions until the tests are passed. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
Other Relevant Rulemaking Group 1 airplanes identified in Boeing Alert Service Bulletin 71730A0009, dated March 31, 2020, are identified as airplanes with a concurrent requirement: Boeing Alert Service Bulletin 71730A0003. AD 20071301, Amendment 3915105 72 FR 33852, June 20, 2007 AD 20071301
requires accomplishing the actions specified in Boeing Alert Service Bulletin 71730A0003, Revision 2, dated November 28, 2006. AD 200713
01 requires operators to accomplish the actions changing the wiring for the air data sensor heating system within 24
months after July 25, 2007 the effective date of AD 20071301. The FAA
issued that AD to address the display of suspect or erratic airspeed indications during heavy rain conditions, which could reduce the ability of the flightcrew to maintain the safe flight and landing of the airplane. Since AD
20071301 already requires the concurrent service information, the FAA
has not included Boeing Alert Service Bulletin 71730A0003, Revision 2, dated November 28, 2006, as a concurrent requirement in this AD.
Costs of Compliance The FAA estimates that this AD
affects 113 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:

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