[Federal Register: December 1, 2003 (Volume 68, Number 230)]
[Rules and Regulations]               
[Page 67027-67030]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01de03-7]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-249-AD; Amendment 39-13377; AD 2003-24-08]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to all Boeing Model 737-100, -200, -200C, -300, -400, 
and -500 series airplanes, that currently requires repetitive 
inspections to find cracks, fractures, or corrosion of each carriage 
spindle of the left and right outboard mid-flaps; and corrective 
action, if necessary. That AD also provides for an optional action of 
overhaul or replacement of the carriage spindles. This amendment 
requires repetitive gap checks of the inboard and outboard carriage of 
the outboard mid-flaps to detect fractured carriage spindles; and 
corrective actions, if necessary. This amendment also reduces the 
interval for the existing inspections and revises the overhaul 
procedures. The actions specified in this AD are intended to detect and 
correct cracked, corroded, or fractured carriage spindles and to 
prevent severe flap asymmetry, which could result in reduced control or 
loss of controllability of the airplane. This action is intended to 
address the identified unsafe condition.

DATES: Effective December 4, 2003.
    The incorporation by reference of Boeing Alert Service Bulletin 
737-

[[Page 67028]]

57A1277, Revision 1, dated November 25, 2003, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
December 4, 2003.
    The incorporation by reference of Boeing Alert Service Bulletin 
737-57A1277, dated July 25, 2002, as listed in the regulations, was 
approved previously by the Director of the Federal Register as of 
November 15, 2002 (67 FR 66316, October 31, 2002).
    Comments for inclusion in the Rules Docket must be received on or 
before January 30, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2003-NM-249-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 9-anm-iarcomment@faa.gov. Comments sent via fax or the Internet must 
contain ``Docket No. 2003-NM-249-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in this AD may be obtained from 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT: Robert Hardwick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6457; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: On October 22, 2002, the FAA issued AD 2002-
22-05, amendment 39-12929 (67 FR 66316, October 31, 2002), applicable 
to all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes, to require repetitive inspections to find cracks, fractures, 
or corrosion of each carriage spindle of the left and right outboard 
mid-flaps; and corrective action, if necessary. That AD also provides 
for an optional action of overhaul or replacement of the carriage 
spindles, which would extend the repetitive inspection interval. That 
action was prompted by reports indicating fractures of the carriage 
spindles of the outboard mid-flaps. The actions required by that AD are 
intended to prevent severe flap asymmetry due to fractures of the 
carriage spindles on an outboard mid-flap, which could result in 
reduced control or loss of controllability of the airplane.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has received a report 
indicating that the inboard and outboard carriage spindles (number 7 
and 8 carriage spindles) fractured on the right outboard flap on a 
Boeing Model 737-200 series airplane during approach to landing. The 
flight crew reported a loud bang approximately 500 feet above ground 
level (AGL) followed by the airplane rolling off hard to the right. 
Significant aileron and rudder inputs were required to maintain level 
flight. The fractures resulted from stress-corrosion cracking.
    Investigation revealed that the fractured carriage spindles had 
been ultrasonically inspected per AD 2002-22-05 three weeks before the 
reported incident. Corrosion on the fractured face of the inboard 
carriage spindle indicated that it had failed on some flight previous 
to the failure of the outboard carriage spindle, which had almost no 
corrosion on the fractured surface. The outboard carriage spindle 
failed when the flaps were deployed to detent 40 and at an altitude of 
500 feet AGL.
    If both the inboard and outboard carriage spindles fracture in the 
critical section on an outboard flap when the mid-flaps are deployed 
beyond detent 15, it could result in loss of controllability of the 
airplane.
    The carriage spindles on all Model 737-100, -200C, -300, -400, and 
-500 series airplanes are similar to those on the affected Model 737-
200 series airplanes. Therefore, all of these models may be subject to 
the same unsafe condition.

Other Relevant Rulemaking

    The FAA has previously issued a supplemental notice of proposed 
rulemaking (NPRM) Docket 2002-NM-219-AD (68 FR 62409, November 4, 
2003), applicable to all Boeing Model 737-100, -200, -200C, -300, -400, 
and -500 series airplanes. That action would supersede AD 2002-22-05 to 
require repetitive inspections to find cracks, fractures, or corrosion 
of each carriage spindle of the left and right outboard mid-flaps; and 
corrective action, if necessary. That action also would mandate the 
previously optional overhaul or replacement of the carriage spindles, 
which would end the repetitive inspections required by the existing AD. 
The comment period for that action closes on December 1, 2003.
    This AD affects the proposed requirements of that supplemental 
NPRM. We plan to address any effects of this AD on those proposed 
requirements in future rulemaking.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-57A1277, Revision 1, dated November 25, 2003, which describes the 
following procedures:
    [sbull] Performing repetitive nondestructive test (NDT) inspections 
and general visual inspections for each carriage spindle of the left 
and right outboard mid-flaps to detect cracks, corrosion, or severed 
carriage spindles; and applicable corrective actions, if necessary. The 
corrective actions include removing the carriage spindle and installing 
a new or serviceable carriage spindle.
    [sbull] Performing repetitive gap checks of the inboard and 
outboard carriage of the left and right outboard mid-flaps to determine 
if there is a positive indication of a severed carriage spindle; and 
corrective actions, if necessary. The corrective actions include 
removing the carriage spindle and installing a new or serviceable 
carriage spindle.
    The service bulletin also describes procedures for determining 
whether carriage spindles that are removed can be overhauled, and if 
so, references appropriate overhaul procedures.
    This service bulletin recommends compliance times at the following 
approximate intervals, depending on the flight cycles or years in 
service of the carriage spindle:
    1. For the gap check, ranging from daily to 15 days; and
    2. For the NDT and general visual inspections, ranging from 6 days 
to 180 days.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 2002-22-05 to continue to require repetitive inspections 
to find cracks, fractures, or corrosion of each carriage spindle of the 
left and right outboard mid-flaps; and corrective action, if necessary. 
This AD also requires accomplishment of the actions specified in the 
Boeing Alert Service Bulletin 737-57A1277 described previously, except 
as described below.

[[Page 67029]]

Differences Between This AD and Referenced Service Bulletin

    Operators should note that, for the optional overhaul procedures 
specified in the service bulletin, this AD imposes additional 
requirements to prevent improper nickel plating and hydrogen 
embrittlement. Boeing will add these procedures in the next revision of 
the overhaul manual.
    Operators should also note that, although the Accomplishment 
Instructions of the Boeing Alert Service Bulletin 737-57A1277 describe 
procedures for reporting inspection findings to the manufacturer, this 
AD does not require that action. We do not need this information from 
operators.

Interim Action

    We consider this AD interim action. We are currently considering 
requiring overhaul of the carriage spindles of the left and right 
outboard mid-flaps, which will allow for deferral of the repetitive 
inspections and gap checks required by this AD for some period of time. 
However, the planned compliance time for the overhaul would allow 
enough time to provide notice and opportunity for prior public comment 
on the merits of the overhaul.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    [sbull] For each issue, state what specific change to the AD is 
being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2003-NM-249-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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

0
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

0
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]

0
2. Section 39.13 is amended by removing amendment 39-12929 (67 FR 
66316, October 31, 2002), and by adding a new airworthiness directive 
(AD), amendment 39-13377, to read as follows:

2003-24-08 Boeing: Amendment 39-13377. Docket 2003-NM-249-AD. 
Supersedes AD 2002-22-05, Amendment 39-12929.

    Applicability: All Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct cracked, corroded, or fractured carriage 
spindles and to prevent severe flap asymmetry, which could result in 
reduced control or loss of controllability of the airplane, 
accomplish the following:

Requirements of AD 2002-22-05, Amendment 39-12929

Repetitive Inspections

    (a) Do general visual and nondestructive test (NDT) inspections 
of each carriage spindle (two on each flap) of the left and right 
outboard mid-flaps to find cracks, fractures, or corrosion at the 
later of the times specified in paragraphs (a)(1) and (a)(2) of this 
AD, as applicable, per the Work Instructions of Boeing Alert Service 
Bulletin 737-57A1277, dated July 25, 2002. Repeat the inspection at 
least every 180 days until paragraph (d) or (f) of this AD is done.
    (1) Before the accumulation of 12,000 total flight cycles or 8 
years in-service on new or overhauled carriage spindles, whichever 
is first.
    (2) Within 90 days after November 15, 2002 (the effective date 
of AD 2002-22-05).

    Note 1: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made from within 
touching distance unless otherwise specified. A mirror may be 
necessary to enhance visual access to all exposed surfaces in the 
inspection area. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or droplight and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''


[[Page 67030]]



Corrective Action

    (b) If any crack, fracture, or corrosion is found during any 
inspection required by paragraph (a) of this AD: Before further 
flight, do the applicable actions for that spindle as specified in 
paragraph (b)(1) or (b)(2) of this AD, per the Work Instructions of 
Boeing Alert Service Bulletin 737-57A1277, dated July 25, 2002. Then 
repeat the inspections required by paragraph (a) of this AD every 
12,000 flight cycles or 8 years, whichever is first; on the 
overhauled or replaced spindle only until paragraph (d) or (f) of 
this AD is done.
    (1) If any corrosion is found in the carriage spindle, overhaul 
the spindle.
    (2) If any crack or fracture is found in the carriage spindle, 
replace with a new or overhauled carriage spindle.

New Actions Required by This AD

Compliance Times for New Actions

    (c) The tables in paragraph 1.E., ``Compliance'' of Boeing Alert 
Service Bulletin 737-57A1277, Revision 1, dated November 25, 2003, 
specify the compliance times for this AD. For carriage spindles that 
have accumulated the number of flight cycles or years in service 
specified in the ``Threshold'' column of the tables, accomplish the 
gap check and NDT and general visual inspections specified in 
paragraphs (d) and (f) of this AD within the corresponding interval 
after the effective date of this AD, as specified in the 
``Interval'' column. Repeat the gap check and NDT and general visual 
inspections at the same intervals, except:
    (1) The gap check does not have to be done at the same time as 
an NDT inspection; after doing an NDT inspection, the interval for 
doing the next gap check can be measured from the NDT inspection; 
and
    (2) As carriage spindles gain flight cycles or years in service 
and move from one category in the ``Threshold'' column to another, 
they are subject to the repetitive inspection intervals 
corresponding to the new threshold category.

Work Package 2: Gap Check

    (d) Perform a gap check of the inboard and outboard carriage of 
the left and right outboard mid-flaps to determine if there is a 
positive indication of a severed carriage spindle, in accordance 
with Work Package 2 of paragraph 3.B., ``Work Instructions'' of 
Boeing Alert Service Bulletin 737-57A1277, Revision 1, dated 
November 25, 2003. Accomplishment of the gap check terminates the 
repetitive inspection requirements of paragraphs (a) and (b) of this 
AD.

Work Package 2: Corrective Actions

    (e) If there is a positive indication of a severed carriage 
spindle during the gap check required by paragraph (d) of this AD, 
before further flight, remove the carriage spindle and install a new 
or serviceable carriage spindle in accordance with Work Package 2 of 
paragraph 3.B., ``Work Instructions'' of Boeing Alert Service 
Bulletin 737-57A1277, Revision 1, dated November 25, 2003. If, as a 
result of the detailed inspection described in paragraph 4.b. of 
Work Package 2 of the service bulletin, a carriage spindle is found 
not to be severed and no corrosion or crack is present, it can be 
reinstalled on the mid-flap per the service bulletin.

Work Package 1: Inspections

    (f) Perform a NDT inspection and general visual inspection for 
each carriage spindle of the left and right outboard mid-flaps to 
detect cracks, corrosion, or severed carriage spindles, in 
accordance with Work Package 1 of paragraph 3.B., ``Work 
Instructions'' of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003. Accomplishment of these 
inspections terminates the repetitive inspection requirements of 
paragraphs (a) and (b) of this AD.

Work Package 1: Corrective Actions

    (g) If any corroded, cracked, or severed carriage spindle is 
found during any inspection required by paragraph (f) of this AD, 
before further flight, remove the carriage spindle and install a new 
or serviceable carriage spindle in accordance with Work Package 1 of 
paragraph 3.B., ``Work Instructions'' of Boeing Alert Service 
Bulletin 737-57A1277, Revision 1, dated November 25, 2003.

Parts Installation

    (h) Except as provided in paragraph (e) of this AD: As of the 
effective date of this AD, no person may install on any airplane a 
carriage spindle that has been removed as required by paragraph (e) 
or (g) of this AD, unless it has been overhauled per paragraph 3.B., 
``Work Instructions'' of Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003; except that, to be eligible for 
installation under this paragraph, the carriage spindle must have 
been overhauled per the requirements of paragraph (i) of this AD.
    (i) During accomplishment of any overhaul specified in paragraph 
(h) of this AD, use the procedures specified in paragraphs (i)(1) 
and (i)(2) of this AD during application of the nickel plating to 
the carriage spindle in addition to those specified in Boeing 737 
Standard Overhaul Practices Manual, Chapter 20-42-09.
    (1) The maximum deposition rate of the nickel plating in any one 
plating/baking cycle must not exceed 0.002-inches-per-hour.
    (2) Begin the hydrogen embrittlement relief bake within 10 hours 
after application of the plating, or less than 24 hours after the 
current was first applied to the part, whichever is first.

Exception to Reporting Recommendations in Service Bulletins

    (j) Although the service bulletins recommend that operators 
report inspection findings to the manufacturer, this AD does not 
contain such a reporting requirement.

Alternative Methods of Compliance

    (k)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office (ACO), FAA, is authorized to approve 
alternative methods of compliance (AMOCs) for this AD.
    (2) Alternative methods of compliance, approved previously per 
AD 2002-22-05, amendment 39-12929, are approved as alternative 
methods of compliance for paragraphs (a) and (b) of this AD.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Seattle ACO, to make such findings.

Incorporation by Reference

    (l) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Alert Service Bulletin 737-57A1277, 
dated July 25, 2002; and Boeing Alert Service Bulletin 737-57A1277, 
Revision 1, dated November 25, 2003.
    (1) The incorporation by reference of Boeing Alert Service 
Bulletin 737-57A1277, Revision 1, dated November 25, 2003, is 
approved by the Director of the Federal Register, in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 737-57A1277, dated July 25, 2002, was approved previously 
by the Director of the Federal Register as of November 15, 2002 (67 
FR 66316, October 31, 2002).
    (3) Copies may be obtained from Boeing Commercial Airplanes, 
P.O. Box 3707, Seattle, Washington 98124-2207. 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.

Effective Date

    (m) This amendment becomes effective on December 4, 2003.

    Issued in Renton, Washington, on November 24, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-29784 Filed 11-25-03; 11:56 am]

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