[Federal Register Volume 86, Number 228 (Wednesday, December 1, 2021)]
[Proposed Rules]
[Pages 68171-68173]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-26041]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1017; Project Identifier AD-2021-00495-A]
RIN 2120-AA64


Airworthiness Directives; True Flight Holdings LLC Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all True Flight Holdings LLC Model AA-1, AA-1A, AA-1B, AA-1C, AA-5, 
AA-5A, and AA-5B airplanes. This proposed AD was prompted by the report 
of an accident of an airplane with bondline corrosion and delamination 
of the horizontal stabilizers. This proposed AD would require 
inspecting the wings, fuselage, and stabilizers for bondline 
separation, corrosion, and previous repair. This AD would also require 
repairing or replacing parts and applying corrosion inhibitor as 
necessary. 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 January 18, 
2022.

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) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 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 True 
Flight Holdings LLC, 2300 Madison Highway, Valdosta, GA 31601; phone: 
(229) 242-6337; email: [email protected]. You may view this 
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) 
329-4148. It is also available at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1017.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1017; 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.

FOR FURTHER INFORMATION CONTACT: Fred Caplan, Aviation Safety Engineer, 
Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park, GA 30337; 
phone: (404) 474-5507; fax: (404) 474-5606; email: 
[email protected].

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. FAA-2021-1017; Project Identifier 
AD-2021-00495-A'' 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 Fred 
Caplan, Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 
Columbia Avenue, College Park, GA 30337. 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 of an accident involving a True Flight 
Holdings LLC Model AA-5 airplane that occurred on January 19, 2021. 
During flight, the outboard elevator attach bracket on the horizontal 
stabilizer detached, causing loss of elevator control, flutter, and 
significant damage to the airplane. An investigation identified 
corrosion and delamination of the airplane skin bondlines around the 
area of the horizontal stabilizer where the elevator attach bracket was 
attached, as well as on the trailing edge of the elevator trim tab. 
Field reports have identified additional instances of corrosion and 
delamination of skin bondlines around the horizontal stabilizer and 
other primary structures.
    Model AA-1, AA-1A, AA-1B, AA-1C, AA-5, AA-5A, and AA-5B airplanes 
are similar in design and are constructed using a metal-to-metal 
bonding process. While the bond adhesive remains structurally sound 
throughout the aging process, factors such as corrosion and freezing 
moisture may compromise the structural integrity of some of the bond 
joints. This can lead to delamination of the skin from the primary 
structure.
    Field reports indicate that bondline inspections are not being 
adequately performed during routine inspections, which emphasize a 
visual scanning for problem areas. However, damage can exist with no 
visual indications, and a mechanic might miss damage in a hidden area. 
The FAA has determined that a more thorough inspection procedure is 
necessary to reliably identify corrosion and delamination of bondlines 
in these critical areas.
    This condition, if not addressed, could result in reduced 
structural integrity of the affected airplane component, with 
consequent loss of

[[Page 68172]]

control of the airplane. The FAA is proposing this AD to address the 
unsafe condition on these products.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed True Flight Aerospace Service Bulletin SB-195, 
Revision A, dated June 1, 2021 (True Flight SB-195A). This service 
information specifies procedures for inspecting the primary structure 
and flight controls for bondline separation and corrosion and repairing 
or replacing parts and applying corrosion inhibitor as necessary.
    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 ADDRESSES.

Other Related Service Information

    The FAA also reviewed True Flight Aerospace Service Kit 125, 
Revision B. This service information specifies procedures for repairing 
bondline delamination of flight controls and structures.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in True Flight SB-195A as already described, except as discussed under 
``Differences Between the AD and the Service Information.''

Differences Between This Proposed AD and the Service Information

    This proposed AD would only require the Part A inspections, and not 
the Part B inspection, from True Flight SB-195A. In addition, True 
Flight SB-195A specifies reporting information to the manufacturer, and 
this proposed AD would not.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 2,466 airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                                 Estimated costs
----------------------------------------------------------------------------------------------------------------
                                                                                  Cost per        Cost on U.S.
            Action                  Labor cost             Parts cost             airplane          operators
----------------------------------------------------------------------------------------------------------------
Inspect for delamination and    8 work-hours x     Not applicable...........  $680 per          $1,676,880 per
 corrosion.                      $85 per hour =                                inspection        inspection
                                 $680 per                                      cycle.            cycle.
                                 inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates that it would take 3 work-hours at $85 per work-
hour to do the proposed corrosion inhibitor treatment. Parts would cost 
$104 for a total proposed cost of $359 per airplane. In addition, there 
could be a wide range of areas that may require repair (fuselage, 
stabilizers, and wings) for the delaminated bondlines and/or corrosion 
with potential replacement of the entire component. The FAA has no way 
of determining the number of airplanes that might need these repairs or 
the exact costs for corrective actions needed as a result of the 
proposed inspection, as the damage may vary significantly from airplane 
to airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

True Flight Holdings LLC: Docket No. FAA-2021-1017; Project 
Identifier AD-2021-00495-A.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by January 18, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to True Flight Holdings LLC Model AA-1, AA-1A, 
AA-1B, AA-1C, AA-5, AA-5A, and AA-5B airplanes, all serial numbers, 
certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code: 5330, Fuselage 
Main, Plate/Skin; 5512, Horizontal Stabilizer, Plate/Skin; 5522, 
Elevator, Plates/Skin Structure; 5532, Vertical Stabilizer, Plates/
Skin; 5542, Rudder, Plate/Skin; 5730, Wing, Plates/Skins.

(e) Unsafe Condition

    This AD was prompted by corrosion and delamination of the 
horizontal stabilizer bondlines. The FAA is issuing this AD to 
detect and address cracks, buckles, corrosion,

[[Page 68173]]

delamination, rust, and previous repair of the wings, fuselage, and 
stabilizers. The unsafe condition, if not addressed, could result in 
reduced structural integrity of the affected airplane component with 
consequent loss of control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Inspection of Bondlines of the Wings, Stabilizers, and Aft Fuselage

    Within 100 hours time-in-service after the effective date of 
this AD or within 12 months after the effective date of this AD, 
whichever occurs first, and thereafter at intervals not to exceed 12 
months, inspect the wings, stabilizers, and aft fuselage for 
bondline separation, corrosion, and previous repair and take all 
necessary corrective action before further flight in accordance with 
paragraphs A.1. through A.7. in True Flight Aerospace Service 
Bulletin SB-195, Revision A, dated June 1, 2021. Pay particular 
attention to the areas listed in paragraphs (g)(1) through (3) of 
this AD.
    (1) Bondlines of the horizontal stabilizer outboard rib at the 
elevator bearing support assembly.
    (2) Bondlines of the elevator trim tab inboard rib.
    (3) Bondlines and previous repairs of the trailing edges of the 
elevator trim tabs, elevators, rudder, ailerons, and wings.

 (h) Special Flight Permits

    Special flight permits are prohibited.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Atlanta ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (j)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    (1) For more information about this AD, contact Fred Caplan, 
Aviation Safety Engineer, Atlanta ACO Branch, FAA, 1701 Columbia 
Avenue, College Park, GA 30337; phone: (404) 474-5507; fax: (404) 
474-5606; email: [email protected].
    (2) For service information identified in this AD, contact True 
Flight Holdings LLC, 2300 Madison Highway, Valdosta, GA 31601; 
phone: (229) 242-6337; email: [email protected]. 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) 329-4148.

    Issued on November 23, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-26041 Filed 11-30-21; 8:45 am]
BILLING CODE 4910-13-P