[Federal Register Volume 72, Number 32 (Friday, February 16, 2007)]
[Rules and Regulations]
[Pages 7568-7572]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-2640]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25563; Directorate Identifier 2006-NM-083-AD; 
Amendment 39-14950; AD 2007-04-18]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 23, 24, 24A, 24B, 24B-A, 
24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 
31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, and 55C Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 
24F, 24F-A, 25, 25A, 25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-
21A), 36, 36A, 55, 55B, and 55C airplanes. This AD requires modifying 
the left- and right-hand standby fuel pump switches. This AD also 
requires revising the Emergency and Abnormal Procedures sections of the 
airplane flight manual to advise the flightcrew of the proper 
procedures to follow in the event of failure of the standby fuel pump 
to shut off. This AD results from a report of inadvertent operation of 
a standby fuel pump due to an electrical system malfunction. We are 
issuing this AD to prevent this inadvertent operation, which could 
result in inadvertent fuel transfer by the left or right wing fuel 
system and subsequent over-limit fuel imbalance between the left and 
right wing fuel loads. This imbalance could affect lateral control of 
the airplane which could result in reduced controllability.

DATES: This AD becomes effective March 23, 2007.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of March 23, 
2007.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, 
for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: James Galstad, Aerospace Engineer, 
Mechanical Systems and Propulsion Branch, ACE-116W, FAA, Wichita 
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4135; fax 
(316) 946-4107.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain Learjet Model 
23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 
25B, 25C, 25D, 25F, 28, 29, 31, 31A, 35, 35A (C-21A), 36, 36A, 55, 55B, 
and 55C airplanes. That NPRM was published in the Federal Register on 
August 16, 2006 (71 FR 47154). That NPRM proposed to require modifying 
the left- and right-hand standby fuel pump switches. That NPRM also 
proposed to require revising the Emergency and Abnormal Procedures 
sections of the airplane flight manual (AFM) to advise the flightcrew 
of the proper procedures to follow in the event of failure of the 
standby fuel pump to shut off.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Requests To Withdraw the NPRM

    One private citizen states that the flight department he works for 
operates three Learjet Model 35A airplanes and a Learjet Model 31 
airplane. He adds that the airplanes have never had an inadvertent 
operation of the fuel pumps resulting in an over-limit fuel imbalance. 
He also notes that the fuel crossflow valve must be open in order to 
transfer fuel; this requires two switches to be selected--the standby 
fuel pump and the crossflow valve. He states that even if a standby 
fuel pump is inadvertently activated, no fuel will be transferred 
unless the crossflow valve is also open. He concludes that there is 
already enough protection in the system to avoid an over-limit fuel 
imbalance.

[[Page 7569]]

    We infer that the commenter is stating that an AD is not required. 
We recognize that the crossflow valve must be open for fuel to be 
transferred; however, as the operation of the pump may not be 
recognized by the flightcrew, the transfer valve may be opened in an 
attempt to correct an existing fuel imbalance, creating an even greater 
imbalance. We do not agree that there is enough protection in the 
system to avoid an over-limit fuel imbalance when an electrical 
malfunction provides power to an electric standby pump. This condition 
was found during an accident investigation. We have made no change to 
the AD in this regard.
    Another private citizen states that his organization has operated 
up to 13 Learjet 20 series airplanes (some with 20,000 total airframe 
hours) for almost 20 years and has never encountered the unsafe 
condition. He adds that if this problem were to occur, it should not 
generate an emergency situation but simply an abnormal procedure that 
is addressed by the aircraft checklist. He asks what pertinent 
information leads to the conclusion that an unsafe condition is likely 
to exist or develop on other airplanes. He adds that the condition of 
imbalance caused by inadvertent standby pump operation, as specified in 
the NPRM, is not likely to occur; if it did occur, the flightcrew could 
read the proper procedure in the checklist. He concludes that safety is 
not jeopardized at all.
    We infer that the commenter wants us to withdraw the NPRM; we do 
not agree with the request. We acknowledge that existing airplane 
checklist procedures appear to be adequate, but using previous AFM 
procedures does not ensure that the imbalance will be corrected. Based 
on the data presented to date of over 30 reports of imbalance, we find 
that this AD is warranted. We have made no change to the AD in this 
regard.

Request To Publish Service Information/Incorporate by Reference in NPRM

    The Modification and Replacement Parts Association (MARPA) states 
that ADs are based on service information that originates from the type 
certificate holder or its suppliers. MARPA adds that manufacturer's 
service documents are privately authored instruments, generally having 
copyright protection against duplication and distribution. When a 
service document is incorporated by reference into a public document, 
such as an AD, pursuant to 5 U.S.C. 552(a) and 1 CFR part 51, it loses 
its private, protected status and becomes a public document. MARPA 
notes that if a service document is used as a mandatory element of 
compliance, it should not simply be referenced, but should be 
incorporated by reference. MARPA believes that public laws, by 
definition, should be public, which means they cannot rely upon private 
writings for compliance. MARPA adds that the legal interpretation of a 
document is a question of law, not of fact; therefore, unless the 
service document is incorporated by reference it cannot be considered. 
MARPA is concerned that failure to incorporate essential service 
information could result in a court decision invalidating the AD.
    MARPA also states that service documents incorporated by reference 
should be made available to the public by publication in the Docket 
Management System (DMS), keyed to the action that incorporates those 
documents. MARPA notes that the stated purpose of the incorporation by 
reference method is brevity, to keep from expanding the Federal 
Register needlessly by publishing documents already in the hands of the 
affected individuals. MARPA adds that, traditionally, ``affected 
individuals'' means aircraft owners and operators, who are generally 
provided service information by the manufacturer. MARPA adds that a new 
class of affected individuals has emerged, since the majority of 
aircraft maintenance is now performed by specialty shops instead of 
aircraft owners and operators. MARPA notes that this new class includes 
maintenance and repair organizations, component servicing, and/or 
servicing alternatively certified parts under section 21.303 
(``Replacement and modification parts'') of the Federal Aviation 
Regulations (14 CFR 21.303). MARPA notes that distribution to owners 
may, when the owner is a financing or leasing institution, not actually 
reach the people responsible for accomplishing the AD. Therefore, MARPA 
asks that the service documents deemed essential to the accomplishment 
of the NPRM be incorporated by reference into the regulatory instrument 
and published in DMS.
    We acknowledge MARPA's comments. The Office of the Federal Register 
(OFR) requires that documents that are necessary to accomplish the 
requirements of the AD be incorporated by reference during the final 
rule phase of rulemaking. This final rule incorporates by reference the 
documents necessary for the accomplishment of the requirements mandated 
by this AD. Further, we point out that while documents that are 
incorporated by reference do become public information, as noted by the 
commenter, they do not lose their copyright protection. For that 
reason, we advise the public to contact the manufacturer to obtain 
copies of the referenced service information.
    In regard to MARPA's request to post service bulletins on the 
Department of Transportation's DMS, we are currently in the process of 
reviewing issues surrounding the posting of service bulletins on the 
DMS as part of an AD docket. Once we have thoroughly examined all 
aspects of this issue and have made a final determination, we will 
consider whether our current practice needs to be revised. No change to 
the AD is necessary in response to these comments.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD as proposed.

Costs of Compliance

    There are about 1,613 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this AD, at an average labor rate of $80 
per work hour, depending on airplane configuration.

                                                 Estimated Costs
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                                                                                 Number of U.S.-
           Action                Work hours         Parts           Cost per       registered       Fleet cost
                                                                    airplane        airplanes
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Modification................  Between 4 and    Between $1,426   Between $1,746            1,150  Between
                               12.              and $1,470.      and $2,430.                      $2,007,900 and
                                                                                                  $2,794,500.
AFM Revision................  1..............  None...........  $80............           1,150  $92,000
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[[Page 7570]]

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 this AD:
    (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.
    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

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2007-04-18 Learjet: Amendment 39-14950. Docket No. FAA-2006-25563; 
Directorate Identifier 2006-NM-083-AD.

Effective Date

    (a) This AD becomes effective March 23, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the Learjet models identified in the 
applicable Bombardier service bulletin listed in Table 1 of this AD.

                                   Table 1.--Applicability by Service Bulletin
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   Bombardier service bulletin        Revision level                    Date                  Learjet model(s)
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SB 23-28-6......................  Original..............  April 21, 1998..................  23.
SB 24/25-28-3...................  2.....................  February 21, 1998...............  24, 24A, 24B, 24B-A,
                                                                                             24C, 24D, 24D-A,
                                                                                             24E, 24F, and 24F-A
                                                                                             airplanes; and 25,
                                                                                             25A, 25B, 25C, 25D,
                                                                                             and 25F airplanes.
SB 28/29-28-4...................  3.....................  June 2, 1999....................  28 and 29 airplanes.
SB 31-28-7......................  3.....................  January 26, 2001................  31 and 31A
                                                                                             airplanes.
SB 35/36-28-11..................  4.....................  December 4, 2000................  35 and 35A (C-21A)
                                                                                             airplanes; 36 and
                                                                                             36A airplanes.
SB 55-28-13.....................  3.....................  December 15, 2000...............  55, 55B and 55C
                                                                                             airplanes.
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Unsafe Condition

    (d) This AD results from a report of inadvertent operation of a 
standby fuel pump due to an electrical system malfunction. We are 
issuing this AD to prevent this inadvertent operation, which could 
result in inadvertent fuel transfer by the left or right wing fuel 
system and subsequent over-limit fuel imbalance between the left and 
right wing fuel loads. This imbalance could affect lateral control 
of the airplane which could result in reduced controllability.

Compliance

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

Modification

    (f) Within 24 months after the effective date of this AD: Modify 
the left- and right-hand standby fuel pump switches, in accordance 
with the Accomplishment Instructions of the applicable service 
bulletin identified in Table 1 of this AD.

Airplane Flight Manual (AFM) Revision

    (g) Before further flight after accomplishing the modification 
required by paragraph (f) of this AD: Revise the Emergency and 
Abnormal Procedures sections of the applicable Learjet AFM to advise 
the flightcrew of proper procedures to follow in the event of 
failure of the standby fuel pump to shut off by including the 
information in the applicable Learjet temporary flight manual (TFM) 
changes identified in Table 2 of this AD. This may be done by 
inserting a copy of the TFM changes into the AFM. When the TFM 
changes have been included in the general revisions of the AFM, 
those general revisions may be inserted into the AFM, provided the 
relevant information in the general revisions is identical to that 
in the TFM changes.

[[Page 7571]]



                                              Table 2.--TFM Changes
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       Learjet model(s)           Learjet TFM change            Date                  To the Learjet AFM
----------------------------------------------------------------------------------------------------------------
24, 25, 28, 29, 31, 35, 36,     TFM 96-08............  May 30, 1996.........  24 (FM-004), 24B (FM-006), 24D (FM-
 and 55 airplanes.                                                             009), 24E (FM-011), 24F (FM-012),
                                                                               24 ECR 736 (FM-008), 25 (FM-014),
                                                                               25B/C (FM-016), 25D/F (FM-018),
                                                                               28/29 (FM-100), 31 (FM-112), 31A
                                                                               (FM-121), 35/36 (FM-019), 35A/36A
                                                                               FC-200 (FM-102), 35A/36A FC-530
                                                                               (FM-108), 55 (FM-103), 55B (FM-
                                                                               110), 55C (FM-114).
24, 25, 28, 29, 31, 35, 36,     TFM 96-09............  May 30, 1996.........  24 (FM-004), 24B (FM-006), 24D (FM-
 and 55 airplanes.                                                             009), 24E (FM-011), 24F (FM-012),
                                                                               24 ECR 736 (FM-008), 25 (FM-014),
                                                                               25B/C (FM-016), 25D/F (FM-018),
                                                                               28/29 (FM-100), 31 (FM-112), 31A
                                                                               (FM-121), 35/36 (FM-019), 35A/36A
                                                                               FC-200 (FM-102), 35A/36A FC-530
                                                                               (FM-108), 55 (FM-103), 55B (FM-
                                                                               110), 55C (FM-114).
23 airplanes..................  TFM 98-01............  May 11, 1999.........  23 (FM-003).
23 airplanes..................  TFM 98-02............  May 11, 1999.........  23 (FM-003).
----------------------------------------------------------------------------------------------------------------

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Wichita Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (i) You must use the applicable service information identified 
in Tables 3 and 4 of this AD to perform the actions that are 
required by this AD, unless the AD specifies otherwise. (Only page 1 
of Learjet Temporary Flight Manual Change TFM 96-08, dated May 30, 
1996; and Learjet Temporary Flight Manual Change TFM 96-09, dated 
May 30, 1996; contain the document date, no other pages of the 
document contain this information.) The Director of the Federal 
Register approved the incorporation by reference of these documents 
in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact 
Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, for a 
copy of this service information. You may review copies at the 
Docket Management Facility, U.S. Department of Transportation, 400 
Seventh Street SW., Room PL-401, Nassif Building, Washington, DC; on 
the Internet at http://dms.dot.gov; or at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

                              Table 3.--Service Bulletins Incorporated by Reference
----------------------------------------------------------------------------------------------------------------
       Bombardier service bulletin                Revision level                           Date
----------------------------------------------------------------------------------------------------------------
SB 23-28-6...............................  Original Issue..............  April 21, 1998.
SB 24/25-28-3............................  2...........................  February 21, 1998.
SB 28/29-28-4............................  3...........................  June 2, 1999.
SB 31-28-7...............................  3...........................  January 26, 2001.
SB 35/36-28-11...........................  4...........................  December 4, 2000.
SB 55-28-13..............................  3...........................  December 15, 2000.
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          Table 4.--Temporary Changes Incorporated by Reference
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                                                       To the Learjet
   Learjet Temporary Flight            Date           Airplane Flight
      Manual (TFM) change                                  Manual
------------------------------------------------------------------------
TFM 96-08.....................  May 30, 1996.....  24 (FM-004), 24B (FM-
                                                    006), 24D (FM-009),
                                                    24E (FM-011), 24F
                                                    (FM-012), 24 ECR 736
                                                    (FM-008), 25 (FM-
                                                    014), 25B/C (FM-
                                                    016), 25D/F (FM-
                                                    018), 28/29 (FM-
                                                    100), 31 (FM-112),
                                                    31A (FM-121), 35/36
                                                    (FM-019), 35A/36A FC-
                                                    200 (FM-102), 35A/
                                                    36A FC-530 (FM-108),
                                                    55 (FM-103), 55B (FM-
                                                    110), 55C (FM-114)
TFM 96-09.....................  May 30, 1996.....  24 (FM-004), 24B (FM-
                                                    006), 24D (FM-009),
                                                    24E (FM-011), 24F
                                                    (FM-012), 24 ECR 736
                                                    (FM-008), 25 (FM-
                                                    014), 25B/C (FM-
                                                    016), 25D/F (FM-
                                                    018), 28/29 (FM-
                                                    100), 31 (FM-112),
                                                    31A (FM-121), 35/36
                                                    (FM-019), 35A/36A FC-
                                                    200 (FM-102), 35A/
                                                    36A FC-530 (FM-108),
                                                    55 (FM-103), 55B (FM-
                                                    110), 55C (FM-114)
TFM 98-01.....................  May 11, 1999.....  23 (FM-003)
TFM 98-02.....................  May 11, 1999.....  23 (FM-003)
------------------------------------------------------------------------



[[Page 7572]]

    Issued in Renton, Washington, on February 6, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-2640 Filed 2-15-07; 8:45 am]
BILLING CODE 4910-13-P