[Federal Register Volume 63, Number 173 (Tuesday, September 8, 1998)]
[Proposed Rules]
[Pages 47445-47447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24060]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-129-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Model BAe 146 and 
Model Avro 146-RJ Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain British Aerospace Model 
BAe 146 and Model Avro 146-RJ series airplanes. This proposal would 
require a one-time measurement to determine the thickness of the outer 
links of the side stays of the main landing gear (MLG), and corrective 
actions, if necessary. This proposal also would provide for replacement 
of a thin outer link with a new or serviceable part in lieu of certain 
follow-on inspections. This proposal is prompted by issuance of 
mandatory continuing airworthiness information by a foreign civil 
airworthiness authority. The actions specified by the proposed AD are 
intended to prevent cracking of the outer links of the side stays of 
the MLG, which could result in increased braking distance during 
landing, and consequent runway overrun.

DATES: Comments must be received by October 8, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-129-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from AI(R) American Support , Inc., 13850 Mclearen Road, 
Herndon, Virginia 20171. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-129-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 97-NM-129-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain British Aerospace Model BAe 146 and 
Model Avro 146-RJ series airplanes. The CAA advises that it has 
received a report of cracking on the shoulder of two outer links of a 
side stay of the main landing gear (MLG). Investigation has revealed 
that the insufficient thickness of the outer links on certain Model BAe 
146 and Model Avro 146-RJ series airplanes causes them to be 
susceptible to this type of cracking. In addition, this cracking may 
have been aggravated by insufficient greasing of the spherical bearing, 
which could result in increased stress on the side stay when the gear 
is in transit. Such cracking, if not corrected, could result in 
increased braking distance during landing, and consequent runway 
overrun.

Explanation of Relevant Service Information

    The manufacturer has issued British Aerospace Service Bulletin 
SB.32-144, dated December 11, 1996, which describes procedures for a 
one-time measurement to determine the thickness of the outer links of 
the side stays of the MLG. The measurement involves placing a profile 
gauge over the thinnest section of the outer link profile. For outer 
links on which a profile gauge slips over the profile, the service 
bulletin also describes procedures for follow-on repetitive detailed 
visual inspections to detect cracking of the outer links, and 
replacement of any cracked outer link with a new or serviceable part.
    The British Aerospace service bulletin references Messier-Dowty 
Service Bulletin 146-32-128, dated December 6, 1996, as an additional 
source of service information for accomplishment of the measurement.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition. The CAA 
approved Messier-Dowty Service Bulletin 146-32-128, dated December 6, 
1996; classified British Aerospace Service Bulletin SB.32-144, dated 
December 11, 1996, as mandatory; and issued British airworthiness 
directive 005-12-96 in order to assure the continued airworthiness of 
these airplanes in the United Kingdom.

FAA's Conclusions

    These airplane models are manufactured in the United Kingdom and 
are type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the CAA, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are

[[Page 47446]]

certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require accomplishment of 
the actions specified in the British Aerospace service bulletin 
described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike the procedures described in 
Messier-Dowty Service Bulletin 146-32-128 and British Aerospace Service 
Bulletin SB.32-144, this proposed AD would not permit further flight if 
cracks are detected in the outer links of the side stays of the MLG. 
The FAA has determined that, because of the safety implications and 
consequences associated with such cracking, any subject outer link that 
is found to be cracked must be replaced prior to further flight.
    In addition, operators should note that, for airplanes on which the 
profile gauge slips over the top edge of the outer link profile, the 
service bulletins do not describe a terminating action for the follow-
on repetitive inspections to detect cracking of the outer links. 
However, this proposed AD would allow replacement of a thin outer link 
with a new or serviceable part in lieu of the follow-on inspections.

Cost Impact

    The FAA estimates that 37 airplanes of U.S. registry would be 
affected by this proposed AD. It would take approximately 1 work hour 
per airplane to accomplish the proposed measurement, at an average 
labor rate of $60 per work hour. Required parts would be supplied by 
the manufacturer at no cost to operators. Based on this figure, the 
cost impact of the measurement proposed by this AD on U.S. operators is 
estimated to be $2,220, or $60 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 draft 
regulatory 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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 adding the following new 
airworthiness directive:
British Aerospace Regional Aircraft (Formerly British Aerospace 
Regional Aircraft Limited, Avro International Aerospace Division; 
British Aerospace, PLC; British Aerospace Commercial Aircraft 
Limited): Docket 97-NM-129-AD.

    Applicability: Model BAe 146 and Model Avro 146-RJ series 
airplanes, equipped with side stays of the main landing gear (MLG) 
having part numbers (P/N) listed in Messier-Dowty Service Bulletin 
146-32-128, dated December 6, 1996; certificated in any category.

    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 (c) 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 cracking of the outer links of the side stays of the 
main landing gear (MLG), which could result in increased braking 
distance during landing, and consequent runway overrun, accomplish 
the following:
    (a) Within 500 landings or 60 days after the effective date of 
this AD, whichever occurs later, perform a one-time measurement to 
determine the thickness of the outer links of the side stays of the 
MLG, in accordance with British Aerospace Service Bulletin SB.32-
144, dated December 11, 1996.

    Note 2: The British Aerospace service bulletin references 
Messier-Dowty Service Bulletin 146-32-128, dated December 6, 1996, 
as an additional source of service information for accomplishment of 
the measurement.
    (1) If the profile gauge does not slip over the top edge of the 
outer link profile, no further action is required by this AD.
    (2) If the profile gauge slips over the top edge of the outer 
link profile, prior to further flight, accomplish either paragraph 
(a)(2)(i) or (a)(2)(ii) of this AD.
    (i) Replace the outer link with a new or serviceable part in 
accordance with the service bulletin. After replacement of the outer 
link, no further action is required by this AD.

    Note 3: For purposes of this AD, a ``serviceable'' outer link is 
defined as an outer link that is not cracked and on which a profile 
gauge does not slip over the top edge of the profile, as described 
in the service bulletin.

    (ii) Perform a detailed visual inspection to detect cracking of 
the outer links of the side stays of the MLG, in accordance with the 
service bulletin.
    (A) If no cracking is detected, repeat the detailed visual 
inspection thereafter at intervals not to exceed 4,000 landings.
    (B) If any cracking is detected during any detailed visual 
inspection required by this AD, prior to further flight, replace the 
cracked outer link with a new or serviceable part in accordance with 
the service bulletin. After replacement of the outer link, no 
further action is required by this AD.
    (b) As of the effective date of this AD, no person shall install 
on any airplane a side stay of the MLG having a part number listed 
in paragraph 1.A. of Messier-Dowty Service Bulletin 146-32-128, 
dated December 6, 1996; unless the profile gauge does not slip over 
the profile of the outer links of the side stay, as described in 
British Aerospace Service Bulletin SB.32-144, dated December 11, 
1996.
    (c) An alternative method of compliance or adjustment of the 
compliance time that

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provides an acceptable level of safety may be used if approved by 
the Manager, International Branch, ANM-116, 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, International Branch, ANM-
116.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (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.

    Note 5: The subject of this AD is addressed in British 
airworthiness directive 005-12-96.

    Issued in Renton, Washington, on September 1, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-24060 Filed 9-4-98; 8:45 am]
BILLING CODE 4910-13-P