[Federal Register Volume 59, Number 86 (Thursday, May 5, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-9001]
[[Page Unknown]]
[Federal Register: May 5, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-NM-184-AD; Amendment 39-8884; AD 94-08-12]
Airworthiness Directives; Aerospatiale Model ATR72 Series
Airplanes, Equipped With Dunlop Main Landing Gear Wheels, Part Number
AHA1752 Pre Mod 6
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Aerospatiale Model ATR72 series airplanes, that
requires inspections to detect cracking in the brake side half hub in
the bearing housing area of certain main landing gear (MLG) wheels, and
replacement of the MLG wheel, if necessary. This amendment also
requires the eventual replacement of certain MLG wheels with other
wheels, as terminating action for the repetitive inspections. This
amendment is prompted by in-service experience that indicates the
possibility of fatigue cracking occurring in the subject area. The
actions specified by this AD are intended to prevent failure of the
brake side half hub due to fatigue cracking, which could lead to
separation of the MLG wheel and tire from the axle.
DATES: Effective June 6, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 6, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Dunlop Limited, Aviation Division, Silverton House,
Vincent Square, London SW1P 2PL, United Kingdom. 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 Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Sam Grober, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-1187; fax (206) 227-1320.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to certain Aerospatiale Model ATR72 series airplanes was
published in the Federal Register on November 19, 1993 (58 FR 61038).
That action proposed to require repetitive eddy current inspections to
detect cracking in the bearing housing of the brake side half hub of
Dunlop MLG wheels, part number AHA1752 Pre Mod 6. Additionally, that
action proposed to require that, if any cracked half hub assemblies are
detected, the complete wheel must be replaced. If certain improved
replacement wheels are installed, the repetitive eddy current
inspections may be discontinued. That action also proposed to require
the eventual replacement of all MLG wheels having part number AHA1752
Pre Mod 6 with other (improved) wheels, as terminating action for the
repetitive inspections.
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.
The commenter supports the proposed rule.
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule as proposed.
The FAA estimates that 16 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours per
airplane to accomplish the required actions, and that the average labor
rate is $55 per work hour. Based on these figures, the total cost
impact of the inspection actions on U.S. operators is estimated to be
$1,760, or $110 per airplane, per inspection. Should a cracked half hub
assembly be found, replacement wheel assemblies will be provided by
Dunlop at no charge to the operator.
The required wheel replacement action will require approximately 2
work hours to accomplish, at an average labor charge of $55 per work
hour. Replacement parts will be provided by Dunlop at no charge to the
operators, as part of Dunlop's repair/replacement program. Based on
these figures, the total cost impact of the replacement actions on U.S.
operators is estimated to be $1,760, or $110 per airplane.
The total 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.
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 14 CFR part
39 of the Federal Aviation Regulations as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-08-12 Aerospatiale: Amendment 39-8884. Docket 93-NM-184-AD.
Applicability: Model ATR72 airplanes; equipped with Dunlop main
landing gear (MLG) wheels, part number AHA1752 Pre Mod 6;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the brake side half hub due to fatigue
cracking, which could lead to separation of the MLG wheel and tire
from the axle, accomplish the following:
(a) At the next tire change after the effective date of this AD,
or within 60 days after the effective date of this AD, whichever
occurs later, conduct an eddy current inspection to detect cracking
in the bearing housing of the brake side half hub of Dunlop MLG
wheels, part number AHA1752 Pre Mod 6, in accordance with the
Accomplishment Instructions of Dunlop Limited, Aviation Division,
Service Bulletin AHA1752-32-1069, dated June 28, 1993.
(b) If no cracking is detected, repeat the inspection specified
in paragraph (a) of this AD thereafter at every tire change until
the requirements of paragraph (d) of this AD are accomplished.
(c) If any cracking is detected, prior to further flight,
accomplish one of the following:
(1) Replace the complete MLG wheel with a serviceable MLG wheel
having part number AHA1752 Pre Mod 6. Thereafter, repeat the
inspections specified in paragraph (a) of this AD at every tire
change. Or
(2) Replace the complete MLG wheel with a MLG wheel having part
number AHA1752 Post Mod 6. Such replacement constitutes terminating
action for the inspection requirements of this AD. Or
(3) Replace the complete MLG wheel with a MLG wheel having part
number AHA1890. Such replacement constitutes terminating action for
the inspection requirements of this AD.
(d) Within 6 months after the effective date of this AD, replace
all Dunlop MLG wheels having part number AHA1752 Pre Mod 6, with MLG
wheels having either part number AHA1752 Post Mod 6 or part number
AHA1890. Such replacement constitutes terminating action for the
requirements of this AD.
(e) 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, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate. Operators shall submit their
requests through an appropriate FAA Principal Maintenance Inspector,
who may add comments and then send it to the Manager,
Standardization Branch, ANM-113.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(f) Special flight permits may be issued in accordance with
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the
airplane to a location where the requirements of this AD can be
accomplished.
(g) The inspections shall be done in accordance with Dunlop
Limited, Aviation Division, Service Bulletin AHA1752-32-1069, dated
June 28, 1993. 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 Dunlop Limited,
Aviation Division, Silverton House, Vincent Square, London SW1P 2PL,
United Kingdom. Copies may be inspected at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or
at the Office of the Federal Register, 800 North Capitol Street,
NW., suite 700, Washington, DC.
(h) This amendment becomes effective on June 6, 1994.
Issued in Renton, Washington, on April 8, 1994.
Darrell M. Pederson,
Acting Manager,Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-9001 Filed 5-4-94; 8:45 am]
BILLING CODE 4910-13-U