DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2019-0726; Product Identifier 2019-NM-102-AD]
Airworthiness Directives; De Havilland Aircraft of Canada Limited
(Type Certificate Previously Held by Bombardier, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive
for certain De Havilland Aircraft of Canada Limited Model DHC-8-400
series airplanes. This proposed AD was prompted by reports of wear on
fuel couplings, bonding springs, and sleeves as well as fuel tube end
ferrules and fuel component end ferrules. This proposed AD would
require repetitive inspections of certain parts for discrepancies that
meet specified criteria, and replacement as necessary; repetitive
inspections of certain parts for damage and wear, and rework of parts;
and electrical bonding checks of certain couplings. This proposed AD
would also require revising the existing maintenance or inspection
program, as applicable, to incorporate new or more restrictive
airworthiness limitations. For certain airplanes, this proposed AD
would allow a modification that would terminate the repetitive
inspections. 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 December
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the
instructions for submitting comments.
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 De
Havilland Aircraft of Canada Ltd., Q-Series Technical Help Desk, 123
Garratt Boulevard, Toronto, Ontario M3K 1Y5, Canada; telephone 416-375-
4000; fax 416-375-4539; email firstname.lastname@example.org; internet https://
dehavilland.com. You may view this service information at the FAA,
Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For
information on the availability of this material at the FAA, call 206-
Examining the AD Docket
You may examine the AD docket on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2019-0726;
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, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations is listed above.
Comments will be available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Joseph Catanzaro, Aerospace Engineer,
Airframe and Propulsion Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7366; fax 516-
794-5531; email email@example.com.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2019-0726;
Product Identifier 2019-NM-102-AD" at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this NPRM. The FAA will
consider all comments received by the closing date and may amend this
NPRM because of those comments.
The FAA will post all comments received, without change, to http://www.
regulations.gov, including any personal information you provide.
The FAA will also post a report summarizing each substantive verbal
contact received about this NPRM.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2017-04R2, dated
September 25, 2018 (referred to after this as the Mandatory Continuing
Airworthiness Information, or "the MCAI"), to correct an unsafe
condition for certain De Havilland Aircraft of Canada Limited Model
DHC-8-400 series airplanes.
The FAA has received reports of wear on fuel couplings, bonding
springs, and sleeves as well as fuel tube end ferrules and fuel
component end ferrules. The FAA is proposing this AD to address such
wear, which could reduce the integrity of the electrical bonding paths
through the fuel line and components, and ultimately lead to fuel tank
ignition in the event of a lightning strike. See the MCAI for more
The FAA issued a related NPRM that proposed to amend 14 CFR part 39
by adding an AD that would apply to certain Bombardier, Inc., Model
DHC-8-400 series airplanes. The related NPRM published in the Federal
Register on July 6, 2018 (83 FR 31488). The related NPRM was also
prompted by reports of wear on fuel couplings, bonding springs, and
sleeves as well as fuel tube end ferrules and fuel component end
ferrules. Since the related NPRM was issued, Bombardier developed a new
optional terminating modification for certain Model DHC-8-400 series air-
planes and issued associated service information. In addition, Bombardier
developed new airworthiness limitations related to the identified
unsafe condition. In light of these changes, the FAA has withdrawn the
related NPRM as of August 28, 2018 (84 FR 45119), and is now issuing
this new NPRM for public comment.
You may examine the MCAI in the AD docket on the internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2019-0726.
Related Service Information Under 1 CFR Part 51
Bombardier has issued Service Bulletin 84-28-20, Revision D, dated
November 23, 2018. This service information describes procedures for
repetitive detailed inspections of the clamshell coupling bonding
wires, fuel couplings, and associated sleeves for discrepancies (wear
and damage, including discoloration, worn coating, scuffing and
grooves) that meet specified criteria, and replacement. This service
information also describes procedures for repetitive detailed
inspections for damage and wear of the fuel tube end ferrules, fuel
component end ferrules, and ferrule O-ring flanges, and rework of
Bombardier has also issued Service Bulletin 84-28-21, Revision C,
dated July 13, 2018. This service information describes procedures for
a detailed inspection for damage and wear of the fuel tube end
ferrules, fuel component end ferrules, and ferrule O-ring flanges;
rework (repair, replacement, or blending, as applicable) of parts; and
a retrofit (structural rework) of the fuel couplings, isolators, and
Bombardier has also issued Service Bulletin 84-28-26, Revision A,
dated November 29, 2018. This service information describes procedures
for electrical bonding checks of all threaded couplings on the inboard
vent lines in the left and right wings.
Bombardier has also issued Q400 Dash 8 (Bombardier) Temporary
Revision ALI-00AS, dated April 24, 2018; and Q400 Dash 8 (Bombardier)
Temporary Revision ALI-00AT, dated April 24, 2018. This service
information describes airworthiness limitations for fuel tank systems.
These documents are distinct since they describe different
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.
This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to a bilateral agreement with the State of Design Authority, the FAA
has been notified of the unsafe condition described in the MCAI and
service information referenced above. The FAA is proposing this AD
because the agency evaluated all the relevant information and
determined the unsafe condition described previously is likely to exist
or develop on other products of the same type design.
Proposed Requirements of This NPRM
This proposed AD would require repetitive inspections of the
clamshell coupling bonding wires, fuel couplings, and associated
sleeves for discrepancies that meet specified criteria, and replacement
as necessary; repetitive inspections of the fuel tube end ferrules,
fuel component end ferrules, and ferrule O-ring flanges for damage and
wear, and rework of parts; and electrical bonding checks of all
threaded couplings on the inboard vent lines in the left and right
wings. This proposed AD would also require revising the existing
maintenance or inspection program, as applicable, to incorporate new or
more restrictive airworthiness limitations.
This proposed AD would require revisions to certain operator
maintenance documents to include new actions (e.g., inspections) and
Critical Design Configuration Control Limitations (CDCCLs). Compliance
with these actions and CDCCLs is required by 14 CFR 91.403(c). For
airplanes that have been previously modified, altered, or repaired in
the areas addressed by this proposed AD, the operator may not be able
to accomplish the actions described in the revisions. In this
situation, to comply with 14 CFR 91.403(c), the operator must request
approval for an alternative method of compliance according to paragraph
(p)(1) of this proposed AD.
Costs of Compliance
The FAA estimates that this proposed AD affects 52 airplanes of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:
Estimated Costs for Required Actions *
|268 work-hours x $85 per hour
* Table does not include estimated
costs for revising the maintenance or
The FAA has determined that revising the maintenance or inspection
program takes an average of 90 work-hours per operator, although this
number may vary from operator to operator. In the past, the FAA has
estimated that this action takes 1 work-hour per airplane. Since
operators incorporate maintenance or inspection program changes for
their affected fleet(s), the FAA has determined that a per-operator
estimate is more accurate than a per-airplane estimate. Therefore, the
FAA estimates the total cost per operator to be $7,650 (90 work-hours
$85 per work-hour).
Estimated Costs for Optional Actions
||Cost per product
|525 work-hours x $85 per hour
The FAA estimates the following costs
to do any necessary on-
condition actions that would be required based on the results of any
required or optional actions. The FAA has no way of determining the
number of aircraft that might need these on-condition actions:
Estimated Costs of On-Condition Actions
|174 work-hours x $85 per hour
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
This proposed AD is issued in accordance with authority delegated
by the Executive Director, Aircraft Certification Service, as
authorized by FAA Order 8000.51C. In accordance with that order,
issuance of ADs is normally a function of the Compliance and
Airworthiness Division, but during this transition period, the
Executive Director has delegated the authority to issue ADs applicable
to transport category airplanes and associated appliances to the
Director of the System Oversight Division.
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
(1) Is not a "significant regulatory action" under Executive
(2) Will not affect intrastate aviation in Alaska, and
(3) Will 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
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
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]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness