AD 2005-20-40

[Federal Register Volume 70, Number 197 (Thursday, October 13, 2005)]
[Rules and Regulations]
[Pages 59640-59644]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 05-20265]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20726; Directorate Identifier 2004-NM-265-AD; 
Amendment 39-14337; AD 2005-20-40]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200, -200CB, and -
200PF Series Airplanes

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

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Boeing Model 757-200, -200CB, and -200PF series airplanes. This 
AD requires an inspection of each trailing edge flap transmission 
assembly to determine the part number and serial number, and related 
investigative and corrective actions and part marking if necessary. 
This AD results from a report indicating that cracked flap transmission 
output gears have been discovered during routine overhaul of the 
trailing edge flap transmission assemblies. We are issuing this AD to 
prevent an undetected flap skew, which could result in a flap loss, 
damage to adjacent airplane systems, and consequent reduced 
controllability of the airplane.

[[Page 59641]]


DATES: Effective November 17, 2005.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of November 17, 
2005.

ADDRESSES: You may examine the AD docket on the Internet at <a href="http://dms.dot.gov">http://dms.dot.gov</a> 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 Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Douglas Tsuji, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6487; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the AD docket on the Internet at <a href="http://dms.dot.gov">http://dms.dot.gov</a> 
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 Boeing Model 
757-200, -200CB, and -200PF series airplanes. That NPRM was published 
in the Federal Register on March 30, 2005 (70 FR 16175). That NPRM 
proposed to require an inspection of each trailing edge flap 
transmission assembly to determine the part number and serial number, 
and related investigative and corrective actions and part marking if 
necessary.

Comments

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

Support for NPRM

    One commenter, the manufacturer, concurs with the content of the 
NPRM.

Request To Allow Maintenance Records Check

    Two commenters request that we revise the NPRM to allow a 
maintenance records check to determine if any affected transmission 
assembly is installed upon an airplane. One commenter states that it 
tracks all its flap transmission assemblies by part number (P/N) and 
serial number (S/N) in order to record all time and cycle information 
for each of these units. The commenter asserts that since Boeing 
Special Attention Service Bulletin (SASB) 757-27-0150, dated December 
9, 2004, specifies all suspect flap transmission assemblies by P/N and 
S/N, it should be allowed to use these data to demonstrate compliance 
with the NPRM. Another commenter states that it recently updated the P/
N and S/N installation records for all transmission assembly positions 
affected by the NPRM and that these records show that none of the 
affected assemblies are installed on its airplanes. The second 
commenter states that the wording of the NPRM prevents it from using 
these data to demonstrate compliance with the NPRM and requires it to 
physically view all P/Ns on its airplanes. Since Boeing SASB 757-27-
0150 specifies 75 hours per airplane to gain access, inspect, and close 
access for the eight transmission assemblies, the second commenter 
asserts that this proposed requirement is excessively onerous.
    We agree with this request. If an operator can clearly demonstrate 
that the maintenance records for an airplane establish that no suspect 
transmission assembly is installed on that airplane, the records check 
is acceptable for compliance with the P/N and S/N inspection 
requirement of the NPRM. Therefore, we have revised paragraph (f) in 
this AD to permit a maintenance records check instead of the required 
inspection.

Request To Allow Replacement of Transmission Assembly

    One commenter requests that we revise the NPRM to allow replacing a 
transmission assembly having a defective output gear with a compliant 
transmission. The commenter states that it does not have the means to 
repair and test the transmission itself and anticipates sending any 
suspect transmission to a repair facility for inspection, test, and 
marking.
    We agree with this request. Since the intent of the AD is to remove 
defective transmission assembly output gears from service, this can be 
accomplished either by replacing the defective output gear with a 
compliant output gear or replacing the entire transmission assembly 
with a compliant transmission assembly. Therefore, we have revised 
paragraph (f) of this AD to permit ``replacing the entire transmission 
assembly with a new or serviceable flap transmission assembly.''

Request To Increase Total Number of Affected Transmission Assemblies

    One commenter requests that we change the number of affected 
transmission assemblies shown in the NPRM. The commenter states that 
there are four different transmission configurations, each having S/Ns 
1 through 325 inclusive, which yields a total of 1,300 affected 
transmission assemblies rather than 325.
    We agree with this request for the reason stated by the commenter. 
Therefore, we have revised the number of suspect transmission 
assemblies from 325 to 1,300 in this AD.

Request To Revise Applicability

    One commenter requests that we revise the applicability of the NPRM 
to include only those airplanes with transmission assemblies installed 
that have the affected P/Ns and S/Ns. The commenter suggests that the 
applicability could be revised to read, instead of the current wording, 
``This AD applies to Boeing Model 757-200, -200CB, and -200PF series 
airplanes, with part number 251N4050-37, -38, -39, or -40 having S/Ns 1 
through 325 inclusive, or part number 251N4022-28, -29, -30 and -31 
having S/Ns 1 through 325 inclusive.''
    We do not agree with this request. We have no means of ensuring 
that every trailing edge flap transmission assembly with part numbers 
251N4050-37, -38, -39, and -40; and 251N4022-28, -29, -30 and -31; each 
having S/Ns 1 through 325 inclusive; can be located for inspection 
without canvassing all Model 757-200, -200CB, and -200PF series 
airplanes. We have not changed this AD in this regard. However, as 
previously discussed, we have revised this AD to permit a maintenance 
records check to locate suspect transmission assemblies instead of the 
required inspection, which should greatly reduce the burden to 
operators.

Requests To Revise Estimated Work Hours

    Two commenters request that we revise the Costs of Compliance 
section of the NPRM to increase the estimated number of work hours 
needed to accomplish the required actions. One commenter states that 
the 1 work hour specified to accomplish the inspection of eight 
trailing edge flap transmission assemblies is considerably less than 
the 75 work hours to accomplish the task specified by Boeing SASB 757-
27-0150. The commenter states that the NPRM does not accurately reflect 
the costs for

[[Page 59642]]

the amount of work required. A second commenter states that the NPRM 
does not assess the impact of the corrective action. The second 
commenter states that unscheduled maintenance in heavy maintenance 
facilities would be required to perform any needed repairs for some 
airplanes. The second commenter states that, in cases where repair is 
needed, the time required to gain and close up access and for return-
to-service actions is considerably greater than the time specified by 
the NPRM and would result in unscheduled time out-of-service. Both 
commenters assert the cost to accomplish the requirements shown in the 
NPRM should more closely reflect the labor costs specified by Boeing 
SASB 757-27-0150 and assert that the discrepancy in the cost estimates 
places undue hardship on operators.
    In reply to the first commenter: We acknowledge that the amount of 
work estimated by the Boeing service bulletin to open and close the 
access ways is considerable. However, the cost information specified 
describes only the direct costs of the specific actions required by 
this AD. Based on the best data available, the manufacturer provided 
the number of work hours necessary to do the required inspection; one 
(1) work hour in this case. This number represents the time necessary 
to perform only the actions actually required by this AD. We recognize 
that, in doing the actions required by an AD, operators may incur 
additional costs in addition to the direct costs. The cost analysis in 
AD rulemaking actions, however, typically does not include additional 
costs such as the time required to gain access and close up, time 
necessary for planning, or time necessitated by other administrative 
actions. Those additional costs may be significant, but may also vary 
greatly among operators, which makes them almost impossible to 
calculate.
    In reply to the second commenter: The economic analysis of an AD is 
limited to the cost of actions that are actually required and does not 
consider the costs of conditional actions, such as repairing a crack 
detected during a required inspection (``repair, if necessary''). Such 
conditional repairs would be required--regardless of AD direction--to 
correct an unsafe condition identified in an airplane and to ensure 
that the airplane is operated in an airworthy condition, as required by 
the Federal Aviation Regulations. In this case, we included the 
manufacturer's estimate of 20 work hours to remove a transmission 
assembly; remove, inspect, and reassemble the transmission output gear; 
and reinstall the transmission assembly, but we have no way of knowing 
how many transmission assemblies will require these actions or what 
additional actions will be needed to retrofit one transmission 
assembly. Therefore, we can't provide any further assessment of the 
total cost impact of the corrective action.
    We have not changed this AD with regard to these comments. However, 
as previously discussed, we have revised paragraph (f) of this AD to 
specify that a maintenance records check is acceptable instead of the 
required inspection. A maintenance records check could greatly reduce 
the burden to operators.

Request To Re-Evaluate Flap Skew Event

    One commenter requests that we re-evaluate the probability of a 
flap skew event and the classification of this condition as an ``unsafe 
condition.'' The commenter states that it has surveyed its own data, 
which indicate that it has 252 affected transmission assemblies, and 
that all of these units had new torque limiters installed because of 
the requirements of AD 2000-04-18, amendment 39-11601 (65 FR 10693). 
The commenter states that during this retrofit process, 221 of the 252 
transmission assemblies were overhauled and had their output gears 
checked for defects per the component maintenance manual (CMM). The 
commenter asserts that, since all operators of the affected airplanes 
are required to accomplish AD 2000-04-18, the commenter's experience 
might be taken as typical of the industry's experience, which could 
mean the quantity of defective output gears has been substantially 
reduced. The commenter asserts this could lead us to decide that no 
unsafe condition exists and, therefore, withdraw the NPRM.
    We do not agree with this request for the following reasons:
    <bullet> The commenter assumes that most affected airplanes are no 
longer subject to the unsafe condition due to industry compliance with 
AD 2000-04-18, which specifies Boeing Service Bulletin 757-27A0127 as a 
source of service information. However, AD 2000-04-18 is applicable 
only to airplanes having line numbers from 1 through 796 inclusive, 
whereas this AD is applicable to airplanes having line numbers from 1 
through 979 inclusive. This leaves 183 airplanes not covered by AD 
2000-04-18.
    <bullet> AD 2000-04-18 requires replacing the transmission 
assemblies with new assemblies incorporating new, improved torque 
limiters or replacing the torque limiters in the transmission 
assemblies with new, improved torque limiters, as provided in CMM 
Chapter 27-51-13. The commenter asserts that it is likely that all 
operators who accomplished this retrofit checked the transmission 
output gears for defects at the same time. We cannot assume that all 
operators checked the output gears during this retrofit, since checking 
the output gears was not specified by the CMM as a required part of the 
retrofit process.
    <bullet> AD 2000-04-18 requires that retrofitted transmission 
assemblies having P/N 251N4050-37, -38, -39, or -40 be reidentified as 
P/N 251N4022-28, -29, -30 or -31, respectively. As already discussed, 
the commenter asserts that such retrofitted and re-identified 
transmission assemblies no longer are subject to the unsafe condition. 
However, Boeing Service Bulletin 757-27-0150 identifies the modified 
assemblies having those new P/Ns 251N4022-28, -29, -30 and -31, and 
having S/Ns 1 through 325 inclusive, as possibly having suspect output 
gears.
    <bullet> The commenter suggests that its experience might be taken 
as typical for the industry and again assumes that most affected 
transmissions are no longer affected by the unsafe condition. As 
discussed earlier, we determined that, instead of 325 suspect 
transmission assemblies, there are actually 1,300 suspect transmission 
assemblies. This larger number indicates the unsafe condition 
represented by the faulty transmission assemblies could be more 
extensive than represented in the NPRM.
    Our reasoning has led us to determine that the possibility of a 
flap skew event remains a significant unsafe condition for an 
unacceptable number of airplanes. We have not changed this AD in this 
regard.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any approved AMOC on 
any airplane to which the AMOC applies.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been received, and determined that air safety and 
the public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

[[Page 59643]]

Costs of Compliance

    There are about 979 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 644 airplanes of U.S. 
registry.
    It will take approximately 1 work hour per airplane to accomplish 
the required inspection at an average labor rate of $65 per work hour. 
Based on this figure, the cost impact of the AD on U.S. operators is 
estimated to be $41,860, or $65 per airplane.
    Removal of a transmission assembly; removal, inspection, and 
reassembly of the transmission output gear; and reinstallation of the 
transmission assembly; if required; will take about 20 work hours per 
transmission assembly, at an average labor rate of $65 per work hour. 
Required parts will cost about $325 per transmission output gear. Based 
on these figures, we estimate the cost of replacement is $1,625 per 
transmission output assembly (there are 8 transmission output 
assemblies per airplane and 1,300 suspect assemblies).

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

    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):

2005-20-40 Boeing: Amendment 39-14337. Docket No. FAA-2005-20726; 
Directorate Identifier 2004-NM-265-AD.

Effective Date

    (a) This AD becomes effective November 17, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 757-200, -200CB, and -200PF 
series airplanes, certificated in any category, as identified in 
Boeing Special Attention Service Bulletin 757-27-0150, dated 
December 9, 2004.

Unsafe Condition

    (d) This AD was prompted by a report indicating that cracked 
flap transmission output gears have been discovered during routine 
overhaul of the trailing edge flap transmission assemblies. We are 
issuing this AD to prevent an undetected flap skew, which could 
result in a flap loss, damage to adjacent airplane systems, and 
consequent reduced controllability of the airplane.

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.

Inspection To Determine Part Number and Serial Number

    (f) Within 60 months after the effective date of this AD: Do an 
inspection of each trailing edge flap transmission assembly to 
determine the part number (P/N) and serial number (S/N) and any 
applicable related investigative and corrective actions and part 
marking, by accomplishing all of the applicable actions specified in 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 757-27-0150, dated December 9, 2004. If, during any related 
investigative action, any transmission output gear is found with a 
defect or crack, before further flight, replace that transmission 
output gear or replace the entire flap transmission assembly with a 
new or serviceable flap transmission assembly. Operators should note 
that, instead of the P/N and S/N inspection required by this AD, a 
review of airplane maintenance records for any trailing edge flap 
transmission assembly is considered acceptable if the P/N and S/N of 
that assembly can be conclusively determined from that review.

Parts Installation

    (g) As of the effective date of this AD, no person may install a 
trailing edge flap transmission assembly, P/N 251N4050-37, -38, -39, 
or -40 or P/N 251N4022-28, -29, -30, or -31; having any S/N 001 
through 325 inclusive; on any airplane; unless the transmission 
assembly has been inspected, and any applicable related 
investigative and corrective actions and part marking has been 
accomplished, in accordance with the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 757-27-0150, dated 
December 9, 2004.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office, 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 14 CFR 
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 Boeing Special Attention Service Bulletin 757-
27-0150, dated December 9, 2004, to perform the actions that are 
required by this AD, unless the AD specifies otherwise. The Director 
of the Federal Register approved the incorporation by reference of 
this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, 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 <a href="http://dms.dot.gov">http://dms.dot.gov</a>; 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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.


[[Page 59644]]


    Issued in Renton, Washington, on September 30, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-20265 Filed 10-12-05; 8:45 am]
BILLING CODE 4910-13-P