[Federal Register Volume 62, Number 122 (Wednesday, June 25, 1997)]
[Rules and Regulations]
[Pages 34161-34163]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-16270]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-73-AD; Amendment 39-10055; AD 97-13-08]
RIN 2120-AA64
Airworthiness Directives; de Havilland Model DHC-8-100 and -300
Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to all de Havilland Model DHC-8-100 and -300 series
airplanes, that currently requires an inspection to detect
discrepancies and damage of the low fuel pressure switch adapter/
snubber (located on each engine fuel heater), and replacement, if
necessary. That AD also requires an inspection to detect gaps or
openings in each nacelle and engine-mounted firewall area, and in
certain weather seals in the nacelles; and correction of discrepancies.
This amendment requires certain new modifications to the nacelles that
will minimize the passage of flammable fluid through the zones of the
nacelle of each engine. The actions specified by this AD are intended
to prevent the spread of fire through these zones in the event of an
explosion during flight, and consequent structural damage to the
airplane.
DATES: Effective July 30, 1997.
The incorporation by reference of de Havilland Alert Service
Bulletin A8-73-14, Revision B, dated April 24, 1992, as listed in the
regulations was approved previously by the Director of the Federal
Register as of September 8, 1992 (57 FR 37872, August 21, 1992).
The incorporation by reference of certain other publications listed
in the regulations is approved by the Director of the Federal Register
as of July 30, 1997.
ADDRESSES: The service information referenced in this AD may be
obtained from Bombardier, Inc., Bombardier Regional Aircraft Division,
Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5. This information
may be examined at the Federal Aviation Administration (FAA), Transport
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton,
Washington; or at the FAA, New York Aircraft Certification Office,
Engine and Propeller Directorate, 10 Fifth Street, Third Floor, Valley
Stream, New York; or at the Office of the Federal Register, 800 North
Capitol Street, NW., Suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Richard Fiesel, Aerospace Engineer,
Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft
Certification Office, Engine and Propeller Directorate, 10 Fifth
Street, Third Floor, Valley Stream, New York 11581; telephone (516)
256-7504; fax (516) 568-2716.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 92-13-11,
amendment 39-8281 (57 FR 37872, August 21, 1992), which is applicable
to all de Havilland Model DHC-8-100 and -300 series airplanes, was
published in the Federal Register on March 18, 1997 (62 FR 12768). That
action proposed to continue to require the actions currently required
by AD 92-13-11, and to add a requirement that the following actions be
performed on each engine nacelle:
Installation of new angle-gasket assemblies on the
firewalls of the lower cowlings, and application of sealant to gaps and
openings in these areas;
Inspection of the upper access panels of each nacelle for
the presence and condition of weather sealing, and application or
reapplication of sealant, if necessary;
Inspection of the firewall areas for gaps and openings at
lap joints, between bolts, and at carry-through fittings and grommets;
and the application of sealant, if necessary;
Modification of the nacelle by replacing Camloc
receptacles made of silicon bronze with receptacles of stainless steel;
Application of additional sealant to the firewall areas
after the Camloc receptacles have been replaced; and
Replacement of the seals on the cowling doors with
improved seals.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
Support for the Proposal
The commenter supports the proposed rule. In addition, the
commenter urges the FAA to mandate a rapid timeline for the rework of
the compartment seals, and suggests that the FAA consider whether the
optional terminating action for the low fuel pressure switch adapter/
snubber should be required. The commenter suggests that the FAA should
consider a warning system for identifying that a failure of the system
and a potential hazard exists in the event the terminating action
remains optional.
The FAA finds that the proposed compliance times specified in this
AD were determined to be appropriate in light of the safety
implications addressed by this AD. However, the FAA will consider the
commenter's suggestions and, if warranted, may consider additional
rulemaking to address these suggestions. No changes have been made to
this final rule in response to the commenter's requests.
Correction to the Proposal
The FAA has become aware of a typographical error that appeared in
paragraph (f) of the proposal. The modification number specified in
that paragraph appeared incorrectly as ``Modification No. 8/1996.''
Paragraph (f) of this final rule has been revised to correctly specify
that modification number as ``Modification No. 8/1966.''
Conclusion
The FAA has determined that air safety and the public interest
require the adoption of the rule with the change previously described.
The FAA has determined that this change will neither increase the
economic burden on any operator nor increase the scope of the AD.
Cost Impact
There are approximately 100 de Havilland Model DHC-8-100 and -300
series airplanes of U.S. registry that will be affected by this AD.
Each inspection of the low fuel pressure switch adapter/snubber
that is currently required by AD 92-13-11 takes approximately 4 work
hours per airplane to accomplish, at an average labor rate of $60 per
work hour. Based on these figures, the cost impact of this currently
required inspection on U.S. operators is estimated to be $24,000, or
$240 per airplane, per inspection.
The inspection for gaps or openings in each nacelle, engine-mounted
firewall area, and certain nacelle weather seals that is currently
required by AD 92-13-11 takes approximately 12 work hours per airplane
to accomplish, at an average labor rate of $60 per work hour. Based on
these figures, the cost impact of this currently required inspection on
[[Page 34162]]
U.S. operators is estimated to be $72,000, or $720 per airplane.
The installation of new angle-gasket assemblies that is required by
this new AD will take approximately 2 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Required
parts will be provided by the manufacturer at no cost to operators.
Based on these figures, the cost impact of this installation on U.S.
operators is estimated to be $12,000, or $120 per airplane.
The inspection of the upper access panels and firewalls of both
nacelles, and the application of labels, that is required by this new
AD will take approximately 7 work hours per airplane to accomplish, at
an average labor rate of $60 per work hour. Required parts will cost
approximately $43 per airplane. Based on these figures, the cost impact
of this inspection and application of labels on U.S. operators is
estimated to be $46,300, or $463 per airplane.
The replacement of the Camloc receptacles with improved receptacles
that is required by this new AD will take approximately 8 work hours
per airplane to accomplish, at an average labor rate of $60 per work
hour. Required parts will cost approximately $15 per airplane. Based on
these figures, the cost impact of this replacement on U.S. operators is
estimated to be $49,500, or $495 per airplane.
The inspection and application of additional sealant to the
firewalls of the nacelles that is required by this new AD will take
approximately 4 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. The cost of required parts is
estimated to be minimal. Based on these figures, the cost impact of
this inspection and application of sealant on U.S. operators is
estimated to be $24,000, or $240 per airplane.
The replacement of the seals on the cowling doors that is required
by this new AD will take approximately 4 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Required
parts will be provided at no cost to operators, or will cost $1,270,
depending on the kit required. Based on these figures, the cost impact
of this replacement on U.S. operators is estimated to be between
$24,000 and $151,000, or between $240 and $1,510 per airplane,
depending on the kit required.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the requirements of this
AD action, and that no operator would accomplish those actions in the
future if this AD were not adopted.
Regulatory Impact
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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from 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 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-8281 (57 FR
37872, August 21, 1992), and by adding a new airworthiness directive
(AD), amendment 39-10055, to read as follows:
97-13-08 De Havilland, Inc.: Amendment 39-10055. Docket 96-NM-73-
AD. Supersedes AD 92-13-11, Amendment 39-8281.
Applicability: All Model DHC-8-100 and -300 series airplanes,
certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 (h) 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, unless accomplished
previously.
To prevent the spread of fire through the zones of each nacelle,
in the event of an explosion during flight, and consequent
structural damage to the airplane, accomplish the following:
Note 2: The requirements of paragraphs (a) and (b) of this AD
are restatements of the same paragraphs that appeared in AD 92-13-
11, amendment 39-8281. These paragraphs require no additional action
by operators who have already completed the specified actions.
(a) For airplanes having serial numbers 3 through 248,
inclusive, on which Modification No. 8/1208 has not yet been
accomplished, accomplish the following:
(1) Within 30 days after September 8, 1992 (the effective date
of AD 92-13-11, amendment 39-8281), remove and inspect the low fuel
pressure switch adapter/snubber located on each engine fuel heater
for damage to threads, indication of over-torque, and for proper
seating, in accordance with the accomplishment instructions of de
Havilland Alert Service Bulletin A8-73-14, Revision B, dated April
24, 1992. If the adapter/snubber is damaged or if evidence of over-
torque is present, prior to further flight, replace the adapter/
snubber with a serviceable part, in accordance with that service
bulletin.
(2) Thereafter, at any time in which the low fuel pressure
switch adapter/snubber assembly is removed, accomplish the
inspection of the assembly as described in paragraph (a)(1) of this
AD.
(3) Installation of Modification 8/1208, in accordance with de
Havilland Service Bulletin 8-28-15, Revision A, dated April 17,
1992, constitutes terminating action for the inspections required by
paragraphs (a)(1) and (a)(2) of this AD.
(b) For all Model DHC-8-100 and -300 series airplanes: Within 30
days after September 8, 1992 (the effective date of AD 92-13-11,
amendment 39-8281), accomplish the procedures specified in
paragraphs (b)(1) and (b)(2) of this AD.
(1) Inspect the nacelle vertical firewall section, firewall
extension, and engine mounted firewall (reference: Maintenance
Manual section 71-30-00) for gaps and openings that could permit
flammable fluid to pass through. Gaps and openings may be found at
lap joints, between bolts, and at carry-through fittings and
grommets. If gaps are found, prior to further flight, seal the gaps
using PR812, Pro-Seal 700, or other approved firewall sealants
(reference: Maintenance Manual section 20-21-20). Allow the sealant
[[Page 34163]]
to cure for at least 4 hours prior to further flight.
(2) Inspect access panels 419AT and 429AT as specified in DHC-8
Maintenance Manual [section 40-10, pages 12 and 14 (reference:
Illustrated Parts Catalog 54-30-00, Figure 5, Items 410 and 420)]
for the presence and condition of the weather seal in the gap
between the panels and the adjacent structure. If the gap is not
sealed, prior to further flight, seal the panels using PR1422,
PR1435, or other sealant specified in the DHC-8 Maintenance Manual,
section 20-21-16. A release agent, applied prior to sealing, also
may be used as specified in DHC-8 Maintenance Manual, section 20-21-
19. Allow the sealant or release agent to cure for at least 4 hours,
prior to further flight.
(c) For airplanes having serial numbers 3 through 137,
inclusive, on which Modification No. 8/1126 has not been installed:
Within 1 year after the effective date of this AD, seal the firewall
of the lower cowling of each engine by installing angle-gasket
assemblies and applying sealant, in accordance with de Havilland
Service Bulletin 8-54-12, dated January 27, 1989.
(d) For airplanes having serial numbers 003 through 331,
inclusive, on which Modification No. 8/1885 has not been installed:
Within 1 year after the effective date of this AD, accomplish the
procedures specified in paragraphs (d)(1), (d)(2), and (d)(3) of
this AD in accordance with de Havilland Service Bulletin S.B. 8-54-
25, Revision `A,' dated July 29, 1994.
(1) Inspect the vertical firewall section, firewall extension,
and engine-mounted firewall of the upper structure of each nacelle,
including the lap joints between bolts and at carry-through fittings
and grommets, to detect gaps and openings through which flammable
fluid could pass, in accordance with the service bulletin. If any
gap or opening is detected, prior to further flight, seal the gap or
opening, in accordance with the service bulletin.
(2) Inspect the upper access panels of each nacelle to detect
the presence and condition of sealant in any gap between each panel
and its adjacent structure, in accordance with the service bulletin.
If there is no sealant or the sealant is discrepant, prior to
further flight, apply or replace sealant, as applicable, in
accordance with the service bulletin.
(3) Apply exterior labels and protective coatings to each access
panel of the left and right nacelle in accordance with the service
bulletin.
(e) For airplanes having serial numbers 003 through 332,
inclusive, on which Modification No. 8/1887 has not been installed:
Within 1 year after the effective date of this AD, replace the
Camloc receptacles in each nacelle with stainless steel receptacles,
and apply additional sealant to the firewall of each nacelle, in
accordance with de Havilland Service Bulletin S.B. 8-54-30, Revision
`B,' dated February 5, 1993.
(f) For airplanes having serial numbers 003 through 357,
inclusive, on which Modification No. 8/1966 has not been installed:
Within 1 year after the effective date of this AD, inspect the
forward and rearward faces of the firewall, firewall extension, and
engine mounted firewall of the lower structure of each nacelle for
any gap or opening at lap joints, between bolts, and at carry-
through fittings and grommets through which flammable fluid could
pass, in accordance with de Havilland Service Bulletin S.B. 8-54-31,
dated March 8, 1994. If any gap or opening is detected, prior to
further flight, apply sealant in accordance with the service
bulletin.
(g) For airplanes having serial numbers 003 through 369,
inclusive, on which Modification No. 8/2001 has not been installed:
Within 1 year after the effective date of this AD, replace the
existing seals on the cowling doors of each nacelle with improved
seals, in accordance with de Havilland Service Bulletin S.B. 8-71-
19, Revision `B,' dated February 24, 1995.
(h) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, New York Aircraft Certification
Office (ACO), FAA, Engine and Propeller Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, New York ACO.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York ACO.
(i) 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.
(j) The actions shall be done in accordance with de Havilland
Alert Service Bulletin A8-73-14, Revision B, dated April 24, 1992;
de Havilland Service Bulletin 8-54-12, dated January 27, 1989; de
Havilland Service Bulletin S.B. 8-54-25, Revision `A', dated July
29, 1994; de Havilland Service Bulletin S.B. 8-54-30, Revision `B',
dated February 5, 1993; de Havilland Service Bulletin S.B. 8-54-31,
dated March 8, 1994; and de Havilland Service Bulletin S.B. 8-71-19,
Revision `B', dated February 24, 1995. The incorporation by
reference of de Havilland Alert Service Bulletin A8-73-14, Revision
B, dated April 24, 1992, was approved previously by the Director of
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51 as of September 8, 1992 (57 FR 37872, August 21, 1992). The
incorporation by reference of the other publications listed in the
regulations 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 Bombardier, Inc., Bombardier Regional Aircraft
Division, Garratt Boulevard, Downsview, Ontario, Canada M3K 1Y5.
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York
Aircraft Certification Office, Engine and Propeller Directorate, 10
Fifth Street, Third Floor, Valley Stream, New York; or at the Office
of the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(k) This amendment becomes effective on July 30, 1997.
Issued in Renton, Washington, on June 16, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-16270 Filed 6-24-97; 8:45 am]
BILLING CODE 4910-13-U
