[Federal Register Volume 60, Number 201 (Wednesday, October 18, 1995)]
[Rules and Regulations]
[Pages 53855-53857]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25441]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 91-CE-46-AD; Amendment 39-9401; AD 95-21-14]
Airworthiness Directives; de Havilland DHC-6 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes Airworthiness Directive (AD) 83-18-
03, which currently requires repetitively inspecting the tailplane
outboard hinge assembly on certain de Havilland DHC-6 series airplanes,
and replacing any cracked tailplane outboard hinge assembly. The
Federal Aviation Administration's policy on aging commuter-class
aircraft is to eliminate or, in certain instances, reduce the number of
certain repetitive short-interval inspections when improved parts or
modifications are available. This action requires eventually modifying
the tailplane outboard hinge arm and tailplane hinge plate with parts
of improved design (Modification No. 6/1799) as terminating action for
the currently required repetitive inspections. The actions specified by
this AD are intended to prevent tailplane failure caused by cracks in
either outboard hinge arm or the hinge plate, which, if not detected
and corrected, could result in loss of control of the airplane.
DATES: Effective December 4, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of December 4, 1995.
ADDRESSES: Service information that applies to this AD may be obtained
from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario,
Canada, M3K 1Y5. This information may also be examined at the Federal
Aviation Administration (FAA), Central Region, Office of the Assistant
Chief Counsel, Attention: Rules Docket 91-CE-46-AD, Room 1558, 601 E.
12th Street, Kansas City, Missouri 64106; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700, Washington,
DC.
FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer, FAA,
New York Aircraft Certification Office, 10 Fifth Street, 3rd Floor,
Valley Stream, New York 11581; telephone (516) 256-7523; facsimile
(516) 568-2716.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an AD that would apply
to
[[Page 53856]]
certain de Havilland DHC-6 series airplanes without Modification No. 6/
1799 incorporated was published in the Federal Register on October 31,
1994 (59 FR 54410). The action proposed to supersede AD 83-18-03 with a
new AD that would (1) initially retain the requirement of repetitively
inspecting the tailplane outboard hinge assembly for cracks, and
replacing any cracked part; and (2) eventually require modifying the
tailplane outboard hinge arm and tailplane hinge plate with parts of
improved design (Modification No. 6/1799) as terminating action for the
currently required repetitive inspections. Accomplishment of the
proposed actions would be in accordance with de Havilland Service
Bulletin No. 6/421, Revision B, dated November 11, 1983.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. No comments were received on the
proposed rule or the FAA's determination of the cost to the public.
After careful review of all available information related to the
subject presented above, the FAA has determined that air safety and the
public interest require the adoption of the rule as proposed except for
minor editorial corrections. The FAA has determined that these minor
corrections will not change the meaning of the AD and will not add any
additional burden upon the public than was already proposed.
The FAA estimates that 141 airplanes in the U.S. registry will be
affected by this AD, that it will take approximately 35 workhours per
airplane to accomplish the required action, and that the average labor
rate is approximately $60 an hour. Parts cost approximately $4,400 per
airplane. Based on these figures, the total cost impact of this AD on
U.S. operators is estimated to be $916,500. This figure is based on the
assumption that no affected airplane owner/operator has accomplished
the required modification.
The intent of the FAA's aging commuter airplane program is to
ensure safe operation of commuter-class airplanes that are in
commercial service without adversely impacting private operators. Of
the approximately 141 airplanes in the U.S. registry that are affected
by this AD, the FAA has determined that approximately 40 percent are
operated in scheduled passenger service. A significant number of the
remaining 60 percent are operated in other forms of air transportation
such as air cargo and air taxi.
This AD allows 2,400 hours time-in-service (TIS) after the
effective date of this AD before mandatory accomplishment of the design
modification. The average utilization of the fleet for those airplanes
in commercial commuter service is approximately 25 to 50 hours TIS per
week. Based on these figures, operators of commuter-class airplanes
involved in commercial operation will have to accomplish the required
modification within 12 to 24 calendar months after this AD becomes
effective. For private owners, who typically operate between 100 to 200
hours TIS per year, this allows 12 to 24 years before the required
modification is mandatory.
The following paragraphs present cost scenarios for airplanes where
no cracks are found and where cracks are found during the inspections,
and where the remaining airplane life is 15 years with an average
annual utilization rate of 1,600 hours TIS. A copy of the full Cost
Analysis and Regulatory Flexibility Determination for this AD may be
examined at the FAA, Central Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 91-CE-46-AD, Room 1558, 601 E.
12th Street, Kansas City, Missouri.
--No Cracks Scenario: Under the provisions of AD 83-18-03, an owner/
operator of a de Havilland DHC-6 series airplane in scheduled service
who operates an average of 1,600 hours TIS annually will inspect every
1,200 hours TIS. This amounts to a remaining airplane life (estimated
15 years) amount of $4,769; this figure is based on the assumption that
no cracks are found during the inspections. This AD requires the same
1,200-hour TIS inspection until 2,400 hours TIS after the effective
date of the AD when the operator has to replace the tailplane outboard
hinge arm assembly (eliminating the need for further repetitive
inspections), which results in a present value cost of $6,574. The
incremental cost of this AD for such an airplane is $1,805
($6,574-$4,769) or $1,309 annualized over the 1.5 years it will take to
accumulate 2,400 hours TIS. An owner of a general aviation airplane who
operates 800 hours TIS annually without finding any cracks during the
1,200-hour TIS inspections will incur a present value incremental cost
of $3,483 ($5,990-$2,507). This amounts to a per year amount of $1,327
over the three years it takes to accumulate 2,400 hours TIS.
--Cracks Found Scenario: Under the provisions of AD 83-18-03, an owner/
operator of a de Havilland DHC-6 series airplane who finds cracks
during an inspection will repair the crack prior to further flight and
resume inspections every 1,200 hours TIS. This AD requires immediate
replacement of the arm assembly if cracks are found during an
inspection as terminating action for the repetitive inspection
requirement. The repair cost is the same as the replacement except that
the repair does not terminate the inspection requirement. For this
reason, this AD results in present-day cost savings, which will
continue to grow over the remaining life of the airplane since
repetitive inspections are not required. Using the assumed 15-year
remaining life, the cost savings for incorporating Modification 6/1799
will be $4,409 for scheduled service airplane owners/operators and
$2,149 for general aviation airplane owners/operators.
The Regulatory Flexibility Act of 1980 (RFA) was enacted by
Congress to ensure that small entities are not unnecessarily or
disproportionally burdened by government regulations. The RFA requires
government agencies to determine whether rules could have a
``significant economic impact on a substantial number of small
entities,'' and, in cases where they could, conduct a Regulatory
Flexibility Analysis in which alternatives to the rule are considered.
FAA Order 2100.14A, Regulatory Flexibility Criteria and Guidance,
outlines FAA procedures and criteria for complying with the RFA. Small
entities are defined as small businesses and small not-for-profit
organizations that are independently owned and operated or airports
operated by small governmental jurisdictions. A ``substantial number''
is defined as a number that is not less than 11 and that is more than
one-third of the small entities subject to a rule, or any number of
small entities judged to be substantial by the rulemaking official. A
``significant economic impact'' is defined by an annualized net
compliance cost, adjusted for inflation, which is greater than a
threshold cost level for defined entity types. FAA Order 2100.14A sets
the size threshold for small entities operating aircraft for hire at 9
aircraft owned and the annualized cost thresholds, adjusted to 1994
dollars, at $69,000 for scheduled operators and $5,000 for unscheduled
operators.
Of the 141 U.S.-registered airplanes affected by this AD, 6
airplanes are owned by the federal government. Of the other 135, one
business owns 26 airplanes, one business owns 9 airplanes, one business
owns 8
[[Page 53857]]
airplanes, one business owns 7 airplanes, one business owns 4
airplanes, two businesses own 3 airplanes each, thirteen businesses own
2 airplanes each, and forty-nine businesses each own 1 airplane.
Because the FAA has no readily available means of obtaining data on
sizes of these entities, the economic analysis for this AD utilizes the
worst case scenario using the lower annualized cost threshold of $5,000
for operators in unscheduled service instead of $69,000 for operators
in scheduled service. With this in mind and based on the above
ownership distribution, the 64 entities owning 3 or fewer airplanes
will not experience a ``significant economic impact'' as defined by FAA
Order 2100.14A. Since the remaining five entities do not constitute a
``substantial number'' as defined in the Order, this AD will not have a
``significant economic impact on a substantial number of small
entities.''
The regulations adopted herein will not have substantial direct
effects 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. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (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); 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. A copy of the final evaluation prepared for this
action is contained in the Rules Docket. A copy of it may be obtained
by contacting the Rules Docket at the location provided under the
caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Airworthiness Directive
(AD) 83-18-03, Amendment 39-4719, and adding a new AD to read as
follows:
95-21-14 de Havilland: Amendment 39-9401; Docket No. 91-CE-46-AD.
Supersedes AD 83-18-03, Amendment 39-4719.
Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200 and DHC-300
airplanes (serial numbers 1 to 810), certificated in any category,
that do not have Modification 6/1799 incorporated in accordance with
the Accomplishment Instructions, Replacement, section of de
Havilland Service Bulletin (SB) No. 6/421, Revision B, dated
November 11, 1983.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (e) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated in the body of this AD, unless
already accomplished.
To prevent tailplane failure caused by cracks in either the
outboard hinge arm or the hinge plate, which, if not detected and
corrected, could result in loss of control of the airplane,
accomplish the following:
(a) Within the next 50 hours time-in-service (TIS) after the
effective date of this AD or within the next 1,200 hours TIS after
the last inspection accomplished in accordance with superseded AD
83-18-03, Amendment 39- 4719, whichever occurs later, inspect the
tailplane outboard hinge arm assembly for cracks in accordance with
the Accomplishment Instructions, Inspection, section of de Havilland
SB No. 6/421, Revision B, dated November 11, 1983.
(1) If cracks are not found, reinspect every 1,200 hours TIS
until Modification 6/1799 (tailplane outboard hinge arm and
tailplane hinge plate) is installed as required by paragraph (b) of
this AD.
(2) If cracks are found, prior to further flight, replace the
tailplane outboard hinge arm assembly with Modification 6/1799 in
accordance with the Accomplishment Instructions, Replacement,
section of de Havilland SB No. 6/421, Revision B, dated November 11,
1983.
(b) Within 2,400 hours TIS after the effective date of this AD,
replace the tailplane outboard hinge arm assembly with Modification
6/1799 in accordance with the Accomplishment Instructions,
Replacement, section of de Havilland SB No. 6/421, Revision B, dated
November 11, 1983, unless already accomplished in accordance with
paragraph (a)(2) of this AD.
(c) Compliance with paragraph (a)(2) or (b) of this AD is
considered terminating action for the inspection requirements of
this AD.
(d) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
(e) An alternative method of compliance or adjustment of the
initial or repetitive compliance times that provides an equivalent
level of safety may be approved by the Manager, New York Aircraft
Certification Office (ACO), FAA, 10 Fifth Street, 3rd Floor, Valley
Stream, New York 11581. The request shall be forwarded through an
appropriate FAA Maintenance Inspector, who may add comments and then
send it to the Manager, New York ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York ACO.
(f) The inspections and modification required by this AD shall
be done in accordance with de Havilland Service Bulletin No. 6/421,
Revision B, dated November 11, 1983. This incorporation by reference
was approved by the Director of the Federal Register in accordance
with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from
de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario M3K
1Y5 Canada. Copies may be inspected at the FAA, Central Region,
Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th
Street, Kansas City, Missouri, or at the Office of the Federal
Register, 800 North Capitol Street, NW., 7th Floor, suite 700,
Washington, DC.
(g) This amendment (39-9401) supersedes AD 83-18-03, Amendment
39-4719.
(h) This amendment (39-9401) becomes effective on December 4,
1995.
Issued in Kansas City, Missouri, on October 6, 1995.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-25441 Filed 10-17-95; 8:45 am]
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