DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23706; Directorate Identifier 2006-NE-03-AD;
Amendment 39-18177; AD 2015-12-04]
RIN 2120-AA64

Airworthiness Directives; Honeywell International Inc. Turboprop
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: We are superseding airworthiness directive (AD) 2006-15-08 for
all Honeywell International Inc. TPE331-1, -2, -2UA, -3U, -3UW, -5, -
5A, -5AB, -5B, -6, -6A, -10, -10AV, -10GP, -10GT, -10P, -10R, -10T, -
10U, -10UA, -10UF, -10UG, -10UGR, -10UR, -11U, -12JR, -12UA, -12UAR,
and -12UHR turboprop engines with certain Honeywell part numbers (P/Ns)
of Woodward fuel control unit (FCU) assemblies, installed. AD 2006-15-
08 required initial and repetitive dimensional inspections of the fuel
control drives for wear, and replacement of the FCU and fuel pump. This
new AD requires initial and repetitive dimensional inspections of the
affected fuel control drives and insertion of certain airplane
operating procedures into the applicable flight manuals. This AD was
prompted by reports of loss of the fuel control drive, leading to
engine overspeed, overtorque, overtemperature, uncontained rotor
failure, and asymmetric thrust in multi-engine airplanes. We are
issuing this AD to prevent failure of the fuel control drive that could
result in damage to the engine and airplane.

DATES: This AD is effective July 22, 2015.

ADDRESSES: For service information identified in this AD, contact
Honeywell International Inc., 111 S 34th Street, Phoenix, AZ 85034-
2802; phone: 800-601-3099; Internet: https://myaerospace.honeywell.com/
wps/portal/!ut/. You may view this service information at the FAA,
Engine & Propeller Directorate, 12 New England Executive Park,
Burlington, MA. For information on the availability of this material at
the FAA, call 781-238-7125.

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-2006-
23706; or in person at the Docket Management Facility between 9 a.m.
and 5 p.m., Monday through Friday, except Federal holidays. The AD
docket contains this AD, the regulatory evaluation, any comments
received, and other information. The address for the Docket Office
(phone: 800-647-5527) is Document Management Facility, U.S. Department
of Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Joseph Costa, Aerospace Engineer, Los
Angeles Aircraft Certification Office, FAA, Transport Airplane
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; phone: 562-
627-5246; fax: 562-627-5210; email: joseph.costa@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to supersede AD 2006-15-08, Amendment 39-14688 (71 FR 41121,
July 20, 2006), (``AD 2006-15-08''). AD 2006-15-08 applied to all
Honeywell International Inc. TPE331-1, -2, -2UA, -3U, -3UW, -5, -5A, -
5AB, -5B, -6, -6A, -10, -10AV, -10GP, -10GT, -10P, -10R, -10T, -10U, -
10UA, -10UF, -10UG, -10UGR, -10UR, -11U, -12JR, -12UA, -12UAR, and -
12UHR turboprop engines with certain Honeywell part numbers (P/Ns) of
Woodward FCU assemblies, installed. The NPRM published in the Federal
Register on March 19, 2014 (79 FR 15261). The NPRM was prompted by
reports of loss of the fuel control drive, leading to engine overspeed,
overtorque, overtemperature, uncontained rotor failure, and asymmetric
thrust in multi-engine airplanes. The NPRM proposed to continue to
require initial and repetitive dimensional inspections of the affected
fuel control drives but would no longer require the installation of a
modified FCU. The NPRM also proposed to require insertion of certain
airplane operating procedures into the applicable flight manuals. We
are issuing this AD to prevent failure of the fuel control drive that
could result in damage to the engine and airplane.

Comments

We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the NPRM (79
FR 15261, March 19, 2014) and the FAA's response to each comment.

Disagreement With the Elimination of Requirement To Install a Modified
FCU

Honeywell International Inc. (Honeywell) and an individual
commenter indicated that the NPRM should mandate the installation of
the FCU because of the benefits it provides. In addition, both
commenters disagreed with the FAA that the modified FCU contributed to
the rate of in-flight shutdowns (IFSDs) and that the inherent risk of
repetitive inspections does not support the elimination of the
overspeed governor (OSG) modification requirement of AD 2006-15-08.
We disagree. We eliminated the mandatory installation of recently
certified, modified FCUs due to the numerous reports of unscheduled
removals and the IFSDs caused by the recent design changes incorporated
in the modified FCU. We did not change this AD.

Request Change to Costs of Compliance

Honeywell indicated that the cost for repetitive inspections is not
accurate. Honeywell estimates that, without a change in design, a
limitless number of inspections would be needed over the life of the
engine.
We agree. Numerous fuel control drive inspections could be needed
over the life of the engine. The Costs of Compliance paragraph was
changed to reflect an annual cost of compliance which was based on the
fleet costs as reflected in the NPRM.

Request To Change the Applicability

Honeywell requested that engines in Group #4 reflect the engines
associated with FCU assembly P/Ns being added to the Applicability
paragraph for added clarity.
We agree. We changed Table 1 to paragraph (c) of this AD to clarify
the Group #4 engine models as follows: ``Group #4 TPE331-3U, -3UW, -5,
-5B, -6, -6A, and -10T''.

Request To Change the Applicability

Honeywell requested that clarification be provided for FCU P/Ns of
Woodward fuel control units. The Applicability paragraph refers to P/Ns
as Woodward P/Ns when the listed P/Ns are Honeywell P/Ns for Woodward
FCUs.
We agree. We changed paragraph (c) of this AD to read, ``. . .
turboprop engines with Honeywell part numbers (P/Ns) for Woodward fuel
control unit (FCU) assemblies listed in Table 1 to paragraph (c) of
this AD, installed.''

Request Redundant Term Be Removed From the Compliance

Honeywell requested that ``spline'' be removed from the fuel
control drive inspection as stated in the Compliance paragraph. This
change is consistent with the Compliance and the Definitions paragraphs
in AD 2006-15-08.
We agree. We changed paragraphs (e)(1)(i) and (e)(2)(ii) to read:
``Inspect the fuel control drive for wear.''

Request To Change Related Information

Honeywell requested that the publications listed in Related
Information, paragraph (i)(2), be referred to as airplane publications
and not as obtainable from Honeywell International. The reason for this
request is that the Airplane Flight Manual (AFM), the Pilot Operating
Handbook (POH), and the Manufacturer's Operating Manual (MOM) are
airplane publications and cannot be obtained from Honeywell.
We agree that the AFM, POH, and the MOM are airplane manuals. As a
result of reviewing this comment, we decided that mentioning all
applicable owners of airplane manuals is unnecessary in the related
information section of this AD.

Request To Change Airplane Operating Procedures

Honeywell requested that reference to the ``Loss of Fuel Control
Drive'' be changed to ``Loss of the drive between the engine driven
fuel pump and the fuel control governor.'' This change would eliminate
confusion between the loss of the accessory drive gearing to the fuel
pump with the loss of the fuel control drive.
We agree that the term ``fuel control drive'' is not a term used in
airplane operating procedures. We removed the term ``fuel control
drive'' from the Airplane Operating Procedures in this AD and made
other changes to simplify and clarify Figure 1 to paragraph (e) of this
AD.

Request To Change Airplane Operating Procedures

One commenter requested a revision of the Operating Procedure
``Warnings'' in the NPRM to clearly address overspeed during start and
immediately after start before the propeller has been removed from the
start locks. This change would provide clarification and enhance
safety.
We disagree. The Loss of Fuel Control Drive causing rapid,
uncommanded acceleration during engine start is as unsafe as the Loss
of Fuel Control Drive immediately after start when the engine is stable
before the propeller is removed from the start locks. However, since
the observed effects for these two conditions are the same, we combined
both instances as ``Rapid, Uncommanded Acceleration During Engine
Start''.

Request To Change Airplane Operating Procedures

The commenter requested changing the operating procedures for when
the propeller is off the start locks to address the rapid uncommanded,
uncontrolled increase in revolutions-per-minute (RPM). The commenter
believes that if the fuel control drive fails when the propeller is off
the start locks the engine's propeller governor will control and
stabilize the engine RPM.
We disagree with the commenter's justification because test data
has shown that the engine propeller governor will not control and
stabilize the engine RPM if the fuel control drive fails when the
propeller is off the start locks. A rapid, uncommanded, uncontrolled
increase in RPM is most evident during partial or full reverse. We
simplified the operating procedure by removing the statement ``Power--
Move power lever to or toward flight idle as required to maintain
engine limits'' with the propeller off the start locks as proposed in
the NPRM. We changed Figure 1 to paragraph (e) of this AD by adding the
following: ``Engine shut down--Move condition lever to EMERGENCY
STOP''.

Conclusion

We 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. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

We estimate that this AD will affect 2,250 engines installed on
airplanes of U.S. registry. We estimate that it will take 8 hours per
engine to perform an FCU inspection. The average labor rate is $85 per
hour. Due to the more frequent inspections proposed by this AD, we
estimate 10% of affected engines will require FCU assembly stub shaft
replacement, and fuel pump or fuel control repair. We also estimate
that repairs will not exceed $10,000 per engine. Based on these
figures, we estimate the cost of this AD on U.S. operators to be
$525,587 per year.

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.
We are 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

We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will 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 that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979),
(3) Will not affect intrastate aviation in Alaska to the extent
that it justifies making a regulatory distinction, and
(4) 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
reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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 removing airworthiness directive (AD)
2006-15-08, Amendment 39-14688 (71 FR 41121, July 20, 2006), and adding
the following new AD: