Voglio sapere a riguardo di…

Federal Register / Vol. 86, No. 89 / Tuesday, May 11, 2021 / Proposed Rules Notice of proposed rulemaking NPRM.

ACTION:

The FAA proposes to adopt a new airworthiness directive AD for all Textron Aviation Inc. Textron Type Certificate previously held by Cessna Aircraft Company Models 210N, 210R, P210N, P210R, T210N, T210R, 177, 177A, 177B, 177RG, and F177RG
airplanes. This proposed AD was prompted by the in-flight break-up of a Model T210M airplane in Australia, due to fatigue cracking that initiated at a corrosion pit, and subsequent corrosion reports on other Model 210-series and Model 177-series airplanes. This proposed AD would require visual and eddy current inspections of the carrythru spar lower cap, corrective action if necessary, application of a protective coating and corrosion inhibiting compound CIC, and reporting the inspection results to the FAA. The FAA
is proposing this AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by June 25, 2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https www.regulations.gov. Follow the instructions for submitting comments.
Fax: 202 4932251.
Mail: U.S. Department of Transportation, Docket Operations, M30, West Building Ground Floor, Room W12140, 1200 New Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9 a.m. and 5
p.m., Monday through Friday, except Federal holidays.
For service information identified in this NPRM, contact Textron Aviation Inc., One Cessna Boulevard, Wichita, KS
67215; phone: 316 5176061; email:
structures@txtav.com; website: https
support.cessna.com. You may view this referenced service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call 816 3294148.
SUMMARY:

Examining the AD Docket You may examine the AD docket at https www.regulations.gov by searching for and locating Docket No.
FAA20201078; 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 NPRM, any comments received, and other information. The street address for Docket Operations is listed above.

VerDate Sep<11>2014

16:39 May 10, 2021

Jkt 253001

FOR FURTHER INFORMATION CONTACT:

Bobbie Kroetch, Aviation Safety Engineer, Wichita ACO Branch, FAA, 1801 Airport Rd, Wichita, KS 67209;
phone: 316 9464155; fax: 316 946
4107; email: bobbie.kroetch@faa.gov or Wichita-COS@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES. Include Docket No.
FAA20201078; Project Identifier AD
202000716A at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.
Except for Confidential Business Information CBI as described in the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to https
www.regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.
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 this NPRM
contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, 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 they will not be placed in the public docket of this NPRM. Submissions containing CBI
should be sent to Bobbie Kroetch, Aviation Safety Engineer, Wichita ACO
Branch, FAA, 1801 Airport Rd, Wichita, KS 67209. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background The FAA received a report that, on May 26, 2019, a Textron Model T210M

PO 00000

Frm 00005

Fmt 4702

Sfmt 4702

25813

airplane experienced an in-flight breakup while performing low-altitude aerial survey operations in Australia. The carry-thru spar failed and resulted in wing separation and loss of control of the airplane. A visual examination of the fracture surface identified fatigue cracking that initiated at a corrosion pit.
The FAA issued an airworthiness concern sheet ACS on June 27, 2019, advising owners and operators of the accident and requesting relevant information about the fleet.
Following the ACS, the FAA received reports of widespread and severe corrosion of the carry-thru spar. Earlier Models 210G, T210G, 210H, T210H, 210J, T210J, 210K, T210K, 210L, T210L, 210M, and T210M airplanes experienced the most widespread and severe corrosion, and the FAA issued AD 20200316 85 FR 10043, February 21, 2020 AD 20200316 as a final rule; request for comments to immediately address the unsafe condition on those airplanes.
The FAA also received reports of corrosion on later Models 210N, P210N, T210N, 210R, P210R, and T210R
airplanes and Model 177-series airplanes. On Models 210N, P210N, T210N, 210R, P210R, and T210R
airplanes, the upper surface of the carrythru spar is covered by fuselage skin and is not exposed to the environment.
This removes the leak paths at the skin splices common to the earlier Model 210 airplanes and reduces the potential for moisture intrusion. Additionally, the later Model 210 airplanes were manufactured with zinc chromate primer applied to all carry-thru spars.
However, the later Model 210 airplanes were also delivered with foam installed along the carry-thru spar lower cap. The foam traps moisture against the lower surface of the carry-thru spar cap, which can aid in the development of corrosion.
The Model 177-series airplanes share a similar carry-thru spar design with the earlier Model 210-series airplanes: The upper surface of the carry-thru spars are exposed, and the spars may not have been delivered with zinc chromate primer applied. Although Model 177series airplanes were not delivered with foam padding installed on the lower surface of the carry-thru spar, corrosion has been reported on the carry-thru spar lower cap. Corrosion of the carry-thru spar lower cap can lead to fatigue cracking or reduced structural strength of the carry-thru spar, which, if not addressed, could result in wing separation and loss of control of the airplane.

E:FRFM11MYP1.SGM

11MYP1