[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]


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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.

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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

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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

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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