[Federal Register Volume 61, Number 190 (Monday, September 30, 1996)]
[Rules and Regulations]
[Pages 50990-50992]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24653]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-72-AD; Amendment 39-9769; AD 96-20-03]
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 DHC-8-100 and -300 series 
airplanes, that currently requires repetitive inspections to detect 
loose bolts at the retract actuator support fitting of the main landing 
gear, and various follow-on actions, if necessary. That AD was prompted 
by a report of loose actuator supporting bolts and cracks in the relief 
radius of the boss at the forward surface of the fittings. This 
amendment adds a requirement to install a new modification, which, when 
accomplished, terminates the repetitive inspections. The actions 
specified by this AD are intended to prevent loss of hydraulic systems 
and reduced controllability of the airplane due to loose actuator 
support bolts or cracks in the relief radius of the boss at the forward 
surface of the fittings.

DATES: Effective November 4, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of Novmeber 4, 1996.

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,

[[Page 50991]]

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: Jon Hjelm, Aerospace Engineer, 
Airframe and Propulsion Branch, ANE-173, FAA, New York Aircraft 
Certification Office, Engine and Propeller Directorate, 10 Fifth 
Street, Third Floor, Valley Stream, New York 11581; telephone (516) 
256-7523; fax (516) 568-2716.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 91-20-12, 
amendment 39-8046 (56 FR 47901, September 23, 1991), which is 
applicable to all deHavilland DHC-8-100 and -300 series airplanes, was 
published in the Federal Register on July 16, 1996 (61 FR 37019). The 
action proposed to supersede AD 91-20-12 to continue to require 
repetitive inspections to detect loose bolts at the retract actuator 
support fitting of the main landing gear (MLG); and, if necessary, to 
require a magnetic particle inspection, replacement of loose bolts, and 
replacement of cracked fittings. In addition, the action proposed to 
require modification of the frame and the retraction actuator fitting 
of the MLG, which would constitute terminating action for the 
repetitive inspection requirements. The action also proposed to revise 
to revise the applicability of the existing AD.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public.

Conclusion

    The FAA has determined that air safety and the public interest 
require the adoption of the rule as proposed.

Cost Impact

    There are approximately 125 de Havilland Model DHC-8-100 and -300 
series airplanes of U.S. registry that will be affected by this 
proposed AD.
    The actions that are currently required by AD 91-20-12, and 
retained in this AD, take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact on U.S. operators of the actions 
currently required is estimated to be $7,500, or $60 per airplane.
    The installation of modified brackets with new fasteners that is 
required by this AD will take approximately 10 work hours per airplane 
to accomplish, at an average labor rate of $60 per work hour. Required 
parts will cost approximately $3,500 per airplane. Based on these 
figures, the cost impact of the installation required on U.S. operators 
is estimated to be $512,500, or $4,100 per airplane.
    The removal of the enamel application (Modification 8/1830) that is 
required by this AD will take approximately 5 work hours per airplane 
to accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact on U.S. operators of the enamel removed 
required of this AD is estimated to be $37,500, or $300 per airplane.
    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 39-8046 (56 FR 
47901, September 23, 1991), and by adding a new airworthiness directive 
(AD), amendment 39-9769, to read as follows:

96-20-03  de Havilland, Inc.: Amendment 39-9769. Docket 95-NM-72-AD.

    Supersedes AD 91-20-12, Amendment 39-8046.
    Applicability: Model DHC-8-100 and -300 series airplanes, serial 
numbers 3 through 400 inclusive, except serial number 391; 
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 (d) 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 loss of hydraulic systems and reduced controllability 
of the airplane due to loose actuator support bolts or cracks in the 
relief radius of the boss at the forward surface of the fittings, 
accomplish the following:
    (a) For Model DHC-8-100 series airplanes: Within 24 hours after 
September 9, 1991 (the effective date of AD 91-15-51, amendment 39-
8016), inspect the three actuator attachment fitting bolts on the 
right- and left-hand main landing gears (MLG) to detect loose bolts 
by applying a torque of not less than 10 foot-pounds to each bolt.
    (1) If no loose bolt is found as a result of the inspection 
required by paragraph (a) of this AD, repeat this inspection 
thereafter at intervals not to exceed 500 landings.
    (2) If any loose bolt is found as a result of the inspection 
required by paragraph (a) of this AD, accomplish paragraphs 
(a)(2)(i), (a)(2)(ii), and (a)(2)(iii) of this AD.
    (i) Prior to further flight, replace the loose bolt with a new 
bolt of the same part number.
    (ii) Within 250 landings after October 7, 1991 (the effective 
date of 91-20-12, amendment 39-8046) accomplish paragraphs 
(a)(2)(ii)(A) and (a)(2)(ii)(B) of this AD.
    (A) Remove the associated support fitting having part number (P/
N) 85410084.

[[Page 50992]]

    (B) Perform a magnetic particle inspection to detect cracks 
throughout the fitting, paying particular attention to the relief 
radius at the forward surface boss. If any crack is detected as a 
result of this inspection, prior to further flight, replace the 
fitting with a serviceable part.
    (iii) Repeat the inspection required by paragraph (a) of this AD 
thereafter at intervals not to exceed 500 landings.
    (b) For Model DHC-8-300 series airplanes: Within 250 landings 
after October 7, 1991 (the effective date of AD 91-20-12, amendment 
39-8046), inspect the three actuator attachment fitting bolts on the 
right- and left-hand ML's to detect loose bolts by applying a torque 
of not less than 10 foot-pounds to each bolt.
    (1) If no loose bolt is found as a result of the inspection 
required by paragraph (b) of this AD, repeat this inspection 
thereafter at intervals not to exceed 500 landings.
    (2) If any loose bolt is found as a result of the inspection 
required by paragraph (a) of this AD, accomplish paragraphs 
(b)(2)(i), (b)(2)(ii), and (b)(2)(iii) of this AD.
    (i) Prior to further flight, replace the loose bolt with a new 
bolt of the same part number.
    (ii) Within 250 landings after October 7, 1991 (the effective 
date of AD 91-20-12, amendment 39-8046), accomplish (b)(2)(ii)(A) 
and (b)(2)(ii)(B) of this AD.
    (A) Remove the associated support fitting (P/N 85410084 for 
Model DHC-8-301 airplanes, and P/N 85411701 for Model DHC-8-311 
airplanes).
    (B) Perform a magnetic particle inspection to detect cracks 
throughout the fitting, pay particular attention to the relief 
radius at the forward surface boss. If any crack is detected as a 
result of this inspection, prior to further flight, replace the 
fitting with a serviceable part.
    (iii) Repeat the inspection required by paragraph (b) of this AD 
thereafter at intervals not to exceed 500 landings.
    (c) Within 90 days after the effective date of this AD, 
accomplish paragraphs (c)(1) and (c)(2), as applicable, of this AD. 
Accomplishment of this paragraph constitutes terminating action for 
the inspections required by paragraphs (a) and (b) of this AD.
    (1) For Model DHC-8-100 and -300 series airplanes, having serial 
numbers 3 through 400 inclusive, except serial number 391: Modify 
the frame and the retraction actuator fitting of the MLG, in 
accordance with de Havilland Service Bulletin S.B. 8-54-34, Revision 
`A', dated July 21, 1995.
    (2) For Model DHC-8-100 and -300 series airplanes, having serial 
number 3 through 332 inclusive: Modify the retraction actuator 
fitting of the MLG, in accordance with de Havilland Service Bulletin 
S.B. 8-54-27, Revision AD, dated August 22, 1994.
    (d) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (e) 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.
    (f) The modifications shall be done in accordance with de 
Havilland Service Bulletin S.B. 8-54-34, Revision `A', dated July 
21, 1995; and de Havilland Service Bulletin S.B. 8-54-27, Revision 
`B', dated August 22, 1994, as applicable. 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 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.
    (g) This amendment becomes effective on November 4, 1996.

    Issued in Renton, Washington, on September 19, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-24653 Filed 9-27-96; 8:45 am]
BILLING CODE 4910-13-U