Tdata AD

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2010-17-19	THE BOEING COMPANY: Amendment 39-16413. Docket No. FAA-2010-0798; Directorate Identifier 2010-NM-174-AD.

EFFECTIVE DATE

(a) This AD becomes effective September 9, 2010.

AFFECTED ADS

(b) This AD supersedes AD 2010-09-05, Amendment 39-16270.

APPLICABILITY

(c) This AD applies to all  The Boeing Company Model 737-600, -700, -700C,
    -800, -900, and -900ER series airplanes; certificated in any category.

SUBJECT

(d) Air Transport Association (ATA) of America Code 27: Flight controls.

UNSAFE CONDITION

(e) This  AD  results  from  reports  of failure of the aft attach lugs on
    elevator tab  control mechanisms,  which resulted  in severe  elevator
    vibration. This AD also results  from reports of gaps in  elevator tab
    control mechanisms and analysis  that additional elevator tab  control
    mechanisms  might  have bearings  that  will come  loose.  The Federal
    Aviation  Administration  is issuing  this  AD to  detect  and correct
    discrepancies  in the  aft attach  lugs  of  the elevator  tab control
    mechanism,  which  could  result   in  elevator  and  tab   vibration.
    Consequent structural failure of the elevator or horizontal stabilizer
    could result in loss of structural integrity and aircraft control.

COMPLIANCE

(f) You  are  responsible  for  having  the  actions  required  by this AD
    performed within  the compliance  times specified,  unless the actions
    have already been done.

RESTATEMENT  OF  CERTAIN  REQUIREMENTS  OF  AD  2010-09-05,  WITH  REVISED
TERMINATING ACTION

REPETITIVE  INSPECTIONS FOR  GROUP 1  AIRPLANES, AS  IDENTIFIED IN  BOEING
ALERT SERVICE BULLETIN 737-27A1297, DATED APRIL 16, 2010

(g) For Group 1 airplanes,  as identified in Boeing Alert Service Bulletin
    737-27A1297, dated April 16, 2010: Except as required by paragraph (h)
    of this AD, within 12 days after April 29, 2010 (the effective date of
    AD  2010-09-05), do  a detailed  inspection for  discrepancies of  the
    inboard and outboard  aft attach lugs  of the left  and right elevator
    control  tab  mechanisms,   in  accordance  with   the  Accomplishment
    Instructions of Boeing Alert Service Bulletin 737-27A1297, dated April
    16, 2010. Repeat the inspection thereafter at intervals not to  exceed
    300 flight hours. Doing the replacement specified in paragraph (l)  of
    this  AD  before  the  effective  date  of  this  AD  terminates   the
    requirements  of  this  paragraph. Doing  the  inspection  required by
    paragraph  (n)  of  this  AD  terminates  the  requirements  of   this
    paragraph.

(h) For Group 1 airplanes as identified  in  Boeing Alert Service Bulletin
    737-27A1297, dated April  16, 2010: Beginning  7 days after  April 29,
    2010, no person may operate an airplane on an extended twin operations
    (ETOPS) flight unless the initial inspection required by paragraph (g)
    of this  AD has  been accomplished.  Doing the  inspection required by
    paragraph  (n)  of  this  AD  terminates  the  requirements  of   this
    paragraph.

ONE-TIME INSPECTION FOR GROUP 2, CONFIGURATION 1 AIRPLANES, AS  IDENTIFIED
IN BOEING ALERT SERVICE BULLETIN 737-27A1297, DATED APRIL 16, 2010

(i) For Group 2,  Configuration 1 airplanes as identified  in Boeing Alert
    Service Bulletin  737-27A1297, dated  April 16,  2010: Within  30 days
    after  April  29,  2010,   do  a  one-time  detailed   inspection  for
    discrepancies of the inboard and outboard aft attach lugs of the  left
    and  right elevator  control tab  mechanisms, in  accordance with  the
    Accomplishment  Instructions  of  Boeing  Alert  Service  Bulletin 737
    -27A1297,  dated  April 16,  2010.  Doing the  inspection  required by
    paragraph  (n)  of  this  AD  terminates  the  requirements  of   this
    paragraph.

CORRECTIVE ACTIONS FOR PARAGRAPHS (G), (I), AND (K) OF THIS AD

(j) If,  during  any  inspection required by paragraph (g), (i), or (k) of
    this AD, any discrepancy is found, before further flight, replace  the
    elevator  tab  control mechanism  by  doing the  actions  specified in
    paragraphs (j)(1) and (j)(2) of this AD.

(1) Do a detailed inspection for discrepancies of the replacement elevator
    tab control mechanism;  and, if no  discrepancy is found,  install the
    replacement elevator  tab control  mechanism; in  accordance with  the
    Accomplishment  Instructions  of  Boeing  Alert  Service  Bulletin 737
    -27A1297, dated April 16, 2010. If any discrepancy is found, then that
    elevator tab  control mechanism  cannot be  installed and  the actions
    specified in  this paragraph  must be  done before  further flight  on
    another replacement elevator tab control mechanism.

(2) Re-inspect  the  installed  elevator  tab  control mechanism using the
    inspection procedure specified in paragraph (i) of this AD.

REPETITIVE INSPECTIONS FOR CERTAIN GROUP 2, CONFIGURATION 1 AIRPLANES,  AS
IDENTIFIED IN BOEING ALERT  SERVICE BULLETIN 737-27A1297, DATED  APRIL 16,
2010

(k) For Group 2,  Configuration 1  airplanes as identified in Boeing Alert
    Service  Bulletin  737-27A1297, dated  April  16, 2010,  on  which the
    elevator control tab mechanism is replaced with a mechanism other than
    a new, Boeing-built mechanism: Within 300 flight hours after doing the
    replacement, do a detailed inspection for discrepancies of the inboard
    and outboard aft  attach lugs of  the left and  right elevator control
    tab mechanisms, in accordance with the Accomplishment Instructions  of
    Boeing  Alert  Service  Bulletin 737-27A1297,  dated  April  16, 2010.
    Repeat the inspection thereafter at intervals not to exceed 300 flight
    hours. Doing  the replacement  specified in  paragraph (l)  of this AD
    before the effective  date of this  AD is terminating  action for this
    paragraph. Doing the inspection required  by paragraph (n) of this  AD
    terminates the requirements of this paragraph.

TERMINATING ACTION FOR PARAGRAPHS  (G), (I), AND (K)  OF THIS AD, IF  DONE
BEFORE THE EFFECTIVE DATE OF THIS AD

(l) Replacing an elevator tab mechanism with a new, Boeing-built mechanism
    before  the effective  date  of  this AD,  as specified  in paragraphs
    (l)(1) and (l)(2) of this  AD, terminates the inspections required  by
    paragraphs (g), (i), and (k)  of this AD. Replacement of  the elevator
    tab control mechanism on or after  the effective date of this AD  does
    not terminate the inspections required by paragraphs (g), (i), and (k)
    of this AD.

NOTE 1: Refer to paragraphs 3.B.7.b.(1)(a)(1) and 3.B.7.b.(1)(a)(2) of the
Accomplishment Instructions of Boeing Alert Service Bulletin  737-27A1297,
dated April 16, 2010, to establish whether the mechanism is Boeing-built.

(1) Do  a  detailed inspection for discrepancies of the new,  Boeing-built
    replacement elevator tab control mechanism; and, if no discrepancy  is
    found,  install  the  replacement elevator  tab control  mechanism; in
    accordance  with  the  Accomplishment  Instructions  of  Boeing  Alert
    Service Bulletin 737-27A1297, dated April 16, 2010. If any discrepancy
    is found, then that elevator tab control mechanism cannot be installed
    and the actions  specified in this  paragraph must be  done on another
    new, Boeing-built replacement elevator tab control mechanism.

(2) Re-inspect the installed elevator  tab  control  mechanism  using  the
    inspection procedure specified in paragraph (i) of this AD.

REPORTING FOR PARAGRAPHS (G), (I), AND (K) OF THIS AD

(m) At the applicable time specified in paragraph (m)(1) or (m)(2) of this
    AD: Submit  a report  of any  findings (positive  and negative) of the
    first inspection required by paragraphs (g), (i), and (k) of this  AD,
    and any positive findings from the repetitive inspections required  by
    paragraphs (g)  and (k)  of this  AD, to  Boeing Commercial  Airplanes
    Group,     Attention:     Manager,     Airline     Support,    e-mail:
    rse.boecom@boeing.com. The report must include the inspection  results
    including a description of any discrepancies found, the airplane  line
    number,  and  the  total  number of  flight  cycles  and  flight hours
    accumulated on  the airplane.  Under the  provisions of  the Paperwork
    Reduction Act (44 U.S.C. 3501  et seq.), the Office of  Management and
    Budget  (OMB)  has approved  the  information collection  requirements
    contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If  the  inspection  was  done  on or after April 29, 2010: Submit the
    report within 10 days after the inspection.

(2) If  the  inspection  was done before April 29, 2010: Submit the report
    within 10 days after April 29, 2010.

NEW REQUIREMENTS OF THIS AD

REPETITIVE INSPECTIONS

(n) At  the  applicable  time  specified  in  paragraph (n)(1), (n)(2), or
    (n)(3) of this AD: Do  a detailed inspection for discrepancies  of the
    inboard and outboard  aft attach lugs  of the left  and right elevator
    tab  control  mechanisms,   in  accordance  with   the  Accomplishment
    Instructions of Boeing Alert Service Bulletin 737-27A1297, Revision 1,
    dated  August 2,  2010. For  Groups 1  and 2  airplanes identified  in
    Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2,
    2010, repeat the inspection thereafter at intervals not to exceed  300
    flight hours, except as provided  by paragraph (t)(2) of this  AD. For
    Group  3 airplanes  identified in  Boeing Alert  Service Bulletin  737
    -27A1297,  Revision 1,  dated August  2, 2010,  repeat the  inspection
    thereafter at intervals  not to exceed  1,800 flight hours,  except as
    required by paragraphs (p) and (t)(2) of this AD. Doing the inspection
    specified in this paragraph terminates the requirements of  paragraphs
    (g), (h), (i), and (k) of this AD.

(1) For  Group 1  airplanes  identified  in  Boeing Alert Service Bulletin
    737-27A1297, Revision 1, dated August 2, 2010: Within 300 flight hours
    after  doing an  inspection in  accordance with  Boeing Alert  Service
    Bulletin 737-27A1297, dated  April 16, 2010,  or within 30  days after
    the effective date of this AD, whichever occurs later.

(2) For  Group 2  airplanes  identified  in  Boeing Alert Service Bulletin
    737-27A1297, Revision  1, dated  August 2,  2010: At  the later of the
    times specified in paragraph (n)(2)(i) and (n)(2)(ii) of this AD.

(i) Before  the  accumulation  of 2,000 total flight cycles or 4,000 total
    flight hours, whichever occurs first.

(ii) Within 14 days after the effective date of this AD.

(3) For  Group 3  airplanes  identified  in  Boeing Alert Service Bulletin
    737-27A1297, Revision  1, dated  August 2,  2010: Within  180 days  or
    1,800 flight  hours after  the effective  date of  this AD,  whichever
    occurs first.

CORRECTIVE ACTIONS

(o) If, during any inspection required by paragraph (n) or (p) of this AD,
    any discrepancy is found, before further flight, replace the  elevator
    tab control  mechanism by  doing the  actions specified  in paragraphs
    (o)(1) and (o)(2) of this AD.

(1) Do a detailed inspection for discrepancies of the replacement elevator
    tab control mechanism;  and, if no  discrepancy is found,  install the
    replacement elevator  tab control  mechanism; in  accordance with  the
    Accomplishment  Instructions  of  Boeing  Alert  Service  Bulletin 737
    -27A1297, Revision  1, dated  August 2,  2010. If  any discrepancy  is
    found, then that  elevator tab control  mechanism cannot be  installed
    and  the  actions specified  in  this paragraph  must  be done  before
    further flight on another replacement elevator tab control mechanism.

(2) Re-inspect the installed elevator  tab  control  mechanism  using  the
    inspection procedure specified in paragraph (n) of this AD.

REDUCED  REPETITIVE  INSPECTION  INTERVAL   FOR  GROUP  3  AIRPLANES,   AS
IDENTIFIED IN BOEING  ALERT SERVICE BULLETIN  737-27A1297, REVISION 1,  ON
WHICH THE MECHANISM IS REPLACED

(p) For  Group 3  airplanes as identified in Boeing Alert Service Bulletin
    737-27A1297, Revision 1, dated August  2, 2010, on which the  elevator
    tab  control  mechanism is  replaced  during the  actions  required by
    paragraph (o)  of this  AD: Within  300 flight  hours after  doing the
    replacement, do a detailed inspection for discrepancies of the inboard
    and outboard  aft attach  lugs of  the replaced  elevator tab  control
    mechanism,  in  accordance  with  the  Accomplishment  Instructions of
    Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2,
    2010.  Repeat  the inspection  of  the replaced  elevator  tab control
    mechanism  thereafter at  intervals not  to exceed  300 flight  hours,
    except as provided by paragraph (t)(2) of this AD.

CREDIT FOR INITIAL INSPECTION DONE  IN ACCORDANCE WITH THE ORIGINAL  ISSUE
OF THE SERVICE BULLETIN

(q) For  Group 1  airplanes as identified in Boeing Alert Service Bulletin
    737-27A1297, Revision  1, dated  August 2,  2010: Inspections  done in
    accordance with Boeing Alert Service Bulletin 737-27A1297, dated April
    16,  2010,  are  acceptable  for  compliance  with  only  the  initial
    inspection required by paragraph (n) of this AD.

REPORTING FOR PARAGRAPHS (N) AND (P) OF THIS AD

(r) At the applicable time specified in paragraph (r)(1) or (r)(2) of this
    AD: Submit  a report  of any  findings (positive  and negative) of the
    first inspection required by paragraphs (n) and (p) of this AD, except
    for airplanes on which a report  required by paragraph (m) of this  AD
    has been submitted, only submit positive findings; and submit a report
    of any positive findings  from the repetitive inspections  required by
    paragraphs (n)  and (p)  of this  AD; to  Boeing Commercial  Airplanes
    Group,     Attention:     Manager,     Airline     Support,    e-mail:
    rse.boecom@boeing.com. The report must include the inspection  results
    including a description of any discrepancies found, the airplane  line
    number,  and  the  total  number of  flight  cycles  and  flight hours
    accumulated on  the airplane.  Under the  provisions of  the Paperwork
    Reduction Act (44 U.S.C. 3501  et seq.), the Office of  Management and
    Budget  (OMB)  has approved  the  information collection  requirements
    contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If the inspection was done on or  after the effective date of this AD:
    Submit the report within 10 days after the inspection.

(2) If  the  inspection  was  done  before  the effective date of this AD:
    Submit the report within 10 days after the effective date of this AD.

NO RETURN OF PARTS

(s) Although Boeing Alert Service Bulletins 737-27A1297,  dated  April 16,
    2010; and  Revision 1,  dated August  2, 2010;  specify to  return the
    affected elevator tab control  mechanism to the manufacturer,  this AD
    does not require the return of the part to the manufacturer.

PARTS INSTALLATION

(t) As of the effective date  of  this  AD,  comply  with  the  conditions
    specified in paragraphs (t)(1) and (t)(2) of this AD.

(1) No  person  may install an elevator tab control mechanism, part number
    251A2430-( ), on any airplane, unless the mechanism has been inspected
    before  and  after   installation  using  the   inspection  procedures
    specified  in  paragraphs  (o)(1)  and  (o)(2)  of  this  AD,  and  no
    discrepancies have been found.

(2) An  elevator  tab  control mechanism, part number 251A2430-( ), may be
    installed, provided that the inspection specified in paragraph (n)  of
    this AD is done within 300 flight hours after doing the  installation,
    and  that the  inspection specified  in paragraph  (n) of  this AD  is
    repeated thereafter at intervals not to exceed 300 flight hours.

ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

(u)(1) The Manager,  Seattle Aircraft Certification Office (ACO), FAA, has
       the authority to approve AMOCs for this AD, if requested using  the
       procedures found in 14 CFR  39.19. Send information to ATTN:  Kelly
       McGuckin,  Aerospace Engineer,  Systems and  Equipment Branch,  ANM
       -130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton,  Washington
       98057-3356; telephone  425-917-6490; fax  425-917-6590. Information
       may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.

(2) To request a different method of compliance or  a different compliance
    time for this AD, follow the procedures in 14 CFR 39.19. Before  using
    any approved AMOC  on any airplane  to which the  AMOC applies, notify
    your  principal  maintenance  inspector  (PMI)  or  principal avionics
    inspector (PAI),  as appropriate,  or lacking  a principal  inspector,
    your local Flight Standards District Office. The AMOC approval  letter
    must specifically reference 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  the Boeing
    Commercial Airplanes Organization Designation Authorization (ODA) that
    has  been  authorized  by  the Manager,  Seattle  ACO,  to  make those
    findings. For a repair method to be approved, the repair must meet the
    certification  basis   of  the   airplane,  and   the  approval   must
    specifically refer to this AD.

(4) AMOCs approved previously in accordance with AD 2010-09-05,  amendment
    39-16270, are approved  as AMOCs for  the corresponding provisions  of
    paragraphs (g), (h), (i), (j), and (k) of this AD.

MATERIAL INCORPORATED BY REFERENCE

(v) You must use  Boeing Alert Service Bulletin 737-27A1297,  dated  April
    16, 2010; and Boeing  Alert Service Bulletin 737-27A1297,  Revision 1,
    dated August  2, 2010;  as applicable;  to do  the actions required by
    this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference  of  Boeing Alert Service Bulletin 737-27A1297,  Revision 1,
    dated August 2, 2010, under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The   Director  of  the  Federal  Register   previously  approved  the
    incorporation  by  reference  of  Boeing  Alert  Service  Bulletin 737
    -27A1297,  dated April 16, 2010, on April 29, 2010 (75 FR 21499, April
    26, 2010).

(3) For  service  information  identified  in  this  AD,   contact  Boeing
    Commercial Airplanes, Attention: Data & Services Management, P.O.  Box
    3707,  MC  2H-65, Seattle,  Washington  98124-2207; telephone  206-544
    -5000,  extension  1; fax  206-766-5680;  e-mail me.boecom@boeing.com;
    Internet https://www.myboeingfleet.com.

(4) You may review copies of the service information at the FAA, Transport
    Airplane Directorate, 1601 Lind  Avenue, SW., Renton, Washington.  For
    information on the availability of this material at the FAA, call  425
    -227-1221.

(5) You  may  also  review  copies  of  the  service  information  that is
    incorporated  by  reference  at  the  National  Archives  and  Records
    Administration (NARA).  For information  on the  availability of  this
    material   at   NARA,   call   202-741-6030,   or   go   to:   http://
    www.archives.gov/federal_register/code_of_federal_regulations/
    ibr_locations.html.

Issued in Renton,  Washington, on August  11, 2010. Ali  Bahrami, Manager,
Transport Airplane Directorate, Aircraft Certification Service.

FOR  FURTHER  INFORMATION  CONTACT:  Kelly  McGuckin,  Aerospace Engineer,
Systems  and  Equipment  Branch, ANM-130S,  FAA,  Seattle  ACO, 1601  Lind
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6490;  fax
(425) 917-6590.

PREAMBLE

AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION: Final rule; request for comments.

SUMMARY: The FAA is superseding an existing airworthiness directive (AD) that applies to all Model 737-600, -700, -700C, -800, -900, and - 900ER series airplanes. The existing AD currently requires, for certain airplanes, a one-time detailed inspection of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms for discrepancies, and replacement of any discrepant elevator tab control mechanism. For certain other airplanes, the existing AD requires that the inspections be done repetitively. Replacing the elevator tab control mechanism with a new Boeing-built mechanism terminates the repetitive inspections in the existing AD. This new AD requires that modified repetitive inspections be done on all airplanes, regardless of accomplishment of the terminating action specified in the existing AD. This AD results from reports of failure of the aft attach lugs on the elevator tab control mechanisms, which resulted in severe elevator vibration. This AD also results from reports of gaps in elevator tab control mechanisms and analysis that additional elevator tab control mechanisms might have bearings that will come loose. We are issuing this AD to detect and correct discrepancies in the aft attach lugs of the elevator tab control mechanism, which could result in elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control.

DATES: This AD becomes effective September 9, 2010.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of September 9, 2010.
On April 29, 2010 (75 FR 21499, April 26, 2010), the Director of the Federal Register approved the incorporation by reference of a certain other publication listed in the AD.
We must receive any comments on this AD by October 12, 2010.

DATES: This AD becomes effective September 9, 2010.

ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http:// www.regulations.gov. Follow the instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Kelly McGuckin, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6490; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

On April 19, 2010, we issued AD 2010-09-05, amendment 39-16270 (75 FR 21499, April 26, 2010). That AD applies to all Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. That AD requires, for certain airplanes, a one-time detailed inspection of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms for discrepancies, and replacement of any discrepant elevator tab control mechanism (the replacement includes performing the detailed inspection on the replacement part before and after installation, and corrective actions if necessary). For certain other airplanes, that AD requires repetitive inspections for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, and replacement if necessary. For airplanes on which the elevator tab control mechanism is replaced with a certain mechanism, that AD requires repetitive inspections for discrepancies of the elevator tab control mechanism and replacement if necessary. Replacing the elevator tab control mechanism with a new Boeing-built mechanism terminates the repetitive inspections in that AD. That AD resulted from reports of failure of the aft attach lugs on the elevator tab control mechanisms, which resulted in severe elevator vibration. One event occurred on an airplane on which a previous AD (emergency AD 2010-06-51, Amendment 39-16250 (75 FR 16648, April 2, 2010)) had been done. The actions specified in AD 2010-09-05 are intended to detect and correct discrepancies in the aft attach lugs of the elevator tab control mechanism, which could result in unwanted elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control.

Actions Since AD 2010-09-05 Was Issued

Since we issued AD 2010-09-05, we have received reports of gaps and loose bearings. For Boeing-built mechanisms, we received reports of gaps but no reports of loose bearings. Also, additional analysis has shown that non-Boeing-built mechanisms installed on airplanes having Line Number 2708 and subsequent might have bearings that will come loose. We have determined that the identified unsafe condition is related to the design of the elevator tab control mechanism. Therefore, all airplanes identified in the applicability of this AD must be repetitively inspected. In addition, installing a Boeing-built mechanism is no longer terminating action for the repetitive inspections.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010. This service bulletin describes procedures for repetitive inspections for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator tab control mechanisms, and replacement if necessary. We referred to Boeing Alert Service Bulletin 737-27A1297, dated April 16, 2010, as the appropriate source of service information for accomplishing certain required actions in AD 2010-09-05. Boeing Alert Service Bulletin 737-27A1297, Revision 1, no longer specifies that installing a Boeing-built mechanism ends the repetitive inspections. Boeing Alert Service Bulletin 737-27A1297, Revision 1, also modifies the inspection procedure by expanding the allowable gap depth in the lug-to-lug interface and the lug-to-spacer interface. Boeing Alert Service Bulletin 737-27A1297, Revision 1, also removes the procedure to determine if replacement mechanisms are Boeing-built or non-Boeing- built.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to supersede AD 2010-09-05. This new AD retains certain requirements of the existing AD. This AD also requires accomplishing the actions specified in Boeing Alert Service Bulletin 737-27A1297, Revision 1, dated August 2, 2010, described previously, except this AD does not require sending discrepant elevator tab control mechanisms to the manufacturer. This AD does require sending the inspection results to the manufacturer.

Change to Existing AD

This AD retains certain requirements of AD 2010-09-05. As a result, the corresponding paragraph identifiers have changed in this AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2010-09-05	Corresponding requirement in this AD
paragraph (m)	paragraph (g)
paragraph (n)	paragraph (h)
paragraph (o)	paragraph (i)
paragraph (p)	paragraph (j)
paragraph (q)	paragraph (k)
paragraph (r)	paragraph (l)
paragraph (s)	paragraph (m)

Interim Action

This AD is considered to be interim action. The manufacturer is currently developing a terminating action that will address the unsafe condition identified in this AD. Once final action has been identified, we might consider further rulemaking.

FAA's Justification and Determination of the Effective Date

Discrepancies, including loose bearings, in the aft attach lugs of the elevator tab control mechanism could result in elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control. Because of our requirement to promote safe flight of civil aircraft and thus, the critical need to ensure the structural integrity of the airplane and the short compliance time involved with this action, this AD must be issued immediately.
Because an unsafe condition exists that requires the immediate adoption of this AD, we find 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

This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2010-0798; Directorate Identifier 2010-NM-174-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.
We will post all comments we receive, without change, to http:// www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, "General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.
For the reasons discussed above, I certify that the 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. 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.
We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA 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. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing amendment 39-16270 (75 FR 21499, April 26, 2010) and by adding the following new airworthiness directive (AD):