FR Doc E7-16424

[Federal Register: August 21, 2007 (Volume 72, Number 161)]
[Proposed Rules]
[Page 46576-46580]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21au07-22]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22623; Directorate Identifier 2004-NM-80-AD]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 767 Airplanes

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

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of
comment period.

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

SUMMARY: The FAA is revising an earlier proposed airworthiness
directive (AD) for all Boeing Model 767 airplanes. The original NPRM
would have required the following actions for the drive mechanism of
the horizontal stabilizer: Repetitive detailed inspections for
discrepancies and loose ball bearings; repetitive lubrication of the
ballnut and ballscrew; repetitive measurements of the freeplay between
the ballnut and the ballscrew; and corrective action if necessary. The
original NPRM resulted from a report of extensive corrosion of a
ballscrew in the drive mechanism of the horizontal stabilizer on a
similar airplane model. This action revises the original NPRM by
including additional initial and repetitive inspections of the
ballscrew-to-ballnut freeplay for certain airplanes, and adding a new
compliance time for those inspections. We are proposing this
supplemental NPRM to prevent an undetected failure of the primary load
path for the ballscrew in the drive mechanism of the horizontal
stabilizer and subsequent wear and failure of the secondary load path,
which could lead to loss of control of the horizontal stabilizer and
consequent loss of control of the airplane.

DATES: We must receive comments on this supplemental NPRM by September
17, 2007.

ADDRESSES: Use one of the following addresses to submit comments on
this supplemental NPRM.
DOT Docket Web site: Go to http://dms.dot.gov and follow

the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your

comments electronically.
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.
Fax: (202) 493-2251.
Hand Delivery: Room W12-140 on the ground floor of the
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle,
Washington 98124-2207, for service information identified in this
proposed AD.

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

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or
arguments regarding this supplemental NPRM. Send your comments to an
address listed in the ADDRESSES section. Include the docket number
``Docket No. FAA-2005-22623; Directorate Identifier 2004-NM-80-AD'' at
the beginning of your comments. We specifically invite comments on the
overall regulatory, economic, environmental, and energy aspects of this
supplemental NPRM. We will consider all comments received by the
closing date and may amend this supplemental NPRM in light of those
comments.
We will post all comments submitted, without change, to http://dms.dot.gov
, including any personal information you provide. We will

also post a report summarizing each substantive verbal contact with FAA
personnel concerning this supplemental NPRM. Using the search function
of that web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review the DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Operations office between 9

a.m. and 5 p.m., Monday through Friday, except Federal holidays. The
Docket Operations office (telephone (800) 647-5527) is located on the
ground floor of the West Building at the street address stated in the
ADDRESSES section. Comments will be available in the AD docket shortly
after the Docket Management System receives them.

Discussion

We proposed to amend 14 CFR part 39 with a notice of proposed
rulemaking (NPRM) for an AD (the ``original NPRM'') for all Boeing
Model 767 airplanes. The original NPRM was published in the Federal
Register on October 7, 2005 (70 FR 58620). The original NPRM proposed
to require the following actions for the drive mechanism of the
horizontal stabilizer: Repetitive detailed inspections for
discrepancies and loose ball bearings; repetitive lubrication of the
ballnut and ballscrew; repetitive measurements of the freeplay between
the ballnut and the ballscrew; and corrective action if necessary.

Actions Since Original NPRM Was Issued

Since we issued the original NPRM, Boeing has revised certain
service information to add initial and repetitive inspections of the
ballscrew-to-ballnut freeplay for certain airplanes, and to add a new
compliance time for those inspections.

Relevant Service Information

We have reviewed the following service bulletins:
Boeing Service Bulletin 767-27A0194, Revision 2, dated
July 13, 2006 (for Model 767-200, -300, and -300F series airplanes);
and
Boeing Service Bulletin 767-27A0195, Revision 2, dated
July 13, 2006 (for Model 767-400ER series airplanes).
The procedures in Revision 2 of the service bulletins are
essentially the same as those in Revision 1 of the service bulletins,
both dated July 21, 2005 (which were referenced in the NPRM as the
appropriate sources of service information for accomplishing the
specified actions); except Revision 2 includes additional requirements
for

[[Page 46577]]

airplanes on which the A55001-22 lock equipment was used to accomplish
the ballscrew-to-ballnut freeplay inspection specified in Revision 1 of
the service bulletins. For airplanes on which the ballscrew-to-ballnut
freeplay inspection was done incorrectly, as specified in section 1.D.
``Description'' of the service bulletins, Revision 2 also adds a new
compliance time for that additional ballscrew-to-ballnut freeplay
inspection of within 60 months after the last inspection, or 60 months
after the delivery date of the airplane, or 18 months after the date on
the service bulletin, whichever occurs latest. Revision 2 also
recommends repeating those inspections thereafter at intervals not to
exceed 72 months. Accomplishing the actions specified in the service
information is intended to adequately address the unsafe condition. We
added a new paragraph (g) to this AD to include these requirements.

Comments

We have considered the following comments on the original NPRM.

Request To Change Relevant Service Information Section

Boeing asks that we change the second paragraph of the Relevant
Service Information section in the original NPRM to read ``For
airplanes on which an FAA-approved low utilization maintenance program
is in effect * * *'' We agree with Boeing that the second paragraph
could be changed for clarification; however, that paragraph is not
included in this supplemental NPRM. We have made no change to the
supplemental NPRM in this regard.

Request To Change Additional Sources of Service Information Table

Boeing asks that we change the table in Note 1 of the original NPRM
titled ``Additional Sources of Service Information'' to reflect that
the airplane maintenance manual is applicable to all Model 767
airplanes, not just Model 767-200 airplanes. Boeing states that the
original NPRM is applicable to all Model 767 airplanes. We agree with
Boeing for the reason provided, and we have changed Note 1 of this
supplemental NPRM accordingly.

Request To Change Compliance Time for Previously Accomplished Actions

Boeing asks that the compliance time specified in paragraph (g) of
the original NPRM (paragraph (h) of the supplemental NPRM) be reduced
from 4,000 to 3,500 flight hours. Boeing states that this compliance
time is specified in section 1.D. ``Description'' of Service Bulletin
767-27A0194, Revision 1. We agree with Boeing for the reason provided.
The compliance time specified in Service Bulletin 767-27A0195, Revision
1, is also 3,500 flight hours. The compliance time specified in the
original NPRM was incorrect; therefore, we have changed the compliance
time in paragraph (h) of this supplemental NPRM accordingly.

Request To Withdraw Original NPRM

Air Transport Association (ATA) on behalf of its member Delta
Airlines, states that operators are already accomplishing the intent of
the original NPRM and there are no instances of the underlying
airworthiness concerns occurring on Model 767 airplanes.
Delta Airlines disagrees with the requirements in the original NPRM
that would mandate what it considers routine maintenance program tasks.
Delta states that it already performs all of these tasks and does not
agree that the tasks should be mandated. Delta adds that the tasks and
compliance intervals specified in the referenced service bulletins are
similar to the tasks and intervals already defined in the Maintenance
Planning Document (MPD). Delta notes that bundling these tasks allows
efficiency, but mandating arbitrary limits through an AD significantly
reduces operator scheduling flexibility and is not merited in this
case.
We infer that the commenters are asking that the original NPRM be
withdrawn; we do not agree. We have determined that a degraded
stabilizer trim actuator can be a safety concern because each airplane
has only one stabilizer trim actuator, which is both a critical system
component and a critical structural component of the airplane. As we
stated in the original NPRM, the unsafe condition is undetected failure
of the primary load path for the ballscrew in the horizontal stabilizer
and subsequent wear and failure of the secondary load path, which could
lead to loss of control of the horizontal stabilizer and consequent
loss of control of the airplane. The proposed maintenance tasks and
intervals must be mandated because of the criticality of the horizontal
stabilizer system, the consequences of not performing the maintenance
tasks, and the adverse service history attributed to problems with the
horizontal stabilizer system on other airplanes. These tasks and
intervals were not chosen arbitrarily, but instead were based on the
minimum maintenance requirements needed to maintain the integrity of
the stabilizer trim system. Although the lubrication and inspection
procedures are normally handled by the procedures in the maintenance
program, these maintenance actions can affect the safety of the
airplane if they are not performed in a timely manner. We do not
mandate the implementation of MPD revisions, and we cannot control
escalation of MPD intervals related to maintenance. We consider it
unacceptable that maintenance intervals can be escalated for economic
reasons when these maintenance actions directly affect the safety of
the airplane. Failure to perform these maintenance tasks at the proper
intervals can lead to an unsafe condition. Therefore, we consider that
mandating the actions in this supplemental NPRM appropriate and
necessary.

Requests To Extend Compliance Times

Delta states that there are no data provided in the original NPRM
to support the proposed compliance time limits. Delta notes that both
of these limits fall short of its C-check visit, and would impose
significant down time and costs to accomplish tasks with such arbitrary
limits. Delta recommends that, if the FAA decides to mandate these
tasks, the limits be written in a manner that allows flexibility in
scheduling, such as ``the later of either (a) or (b), where (a) is
2,000 flight hours or 12 months, whichever occurs first; or (b) every
C-check.''
United Parcel Service (UPS) asks that we consider revising the NPRM
to specify accomplishment of the referenced time-controlled tasks
within paragraph (g) of the original NPRM as follows: ``For airplanes
on which Boeing Maintenance Program Changes are in place to perform
repetitive Inspections/Lubrications/Freeplay checks of the horizontal
stabilizer, within 15,000 flight hours after the last Ballscrew-to-
Ballnut Freeplay Inspection, or 24 months after the effective date,
accomplish applicable actions required by paragraph (f) of this AD.''
UPS states that the continuation of the referenced time-controlled
tasks would provide an equivalent level of safety and relieve
scheduling burdens that might be encountered during the accomplishment
of proposed requirements.
We do not agree with allowing operators to perform the actions at
later compliance times. We cannot specify a letter check for mandatory
inspection intervals because letter checks vary among different
operators and can be escalated. The inspection intervals were
determined from the results of a safety review by means of testing,
failure mode analysis, and fault tree analysis. In developing an
appropriate compliance time for this action, we also considered

[[Page 46578]]

the urgency associated with the subject unsafe condition, the practical
aspect of accomplishing the required actions within an interval of time
that corresponds to the normal scheduled maintenance for most affected
operators, and the recommendation of the manufacturer. However,
according to the provisions of paragraph (k) of this AD, we may approve
requests to adjust the compliance time if the request includes data
that substantiate that the new compliance time would provide an
acceptable level of safety. We have made no change to the supplemental
NPRM in this regard.

Request To Change Paragraph (i) of the Proposed AD

UPS states that no overhaul instructions are provided in the
referenced service bulletins that are specified in paragraph (i) of the
original NPRM, and adds that sufficient inspection requirements are
given in the Component Maintenance Manual (CMM). Therefore, UPS
recommends that paragraph (i) of the original NPRM (Parts Installation)
specify that ``* * * no person may install on any airplane a horizontal
stabilizer trim actuator unless it is new or has been overhauled in
accordance with the CMM; or has been inspected, lubricated, and
measured in accordance with paragraph (f) of this AD.'' UPS states that
the referenced service bulletins do not provide any direction over and
above the requirements of the associated CMM.
We disagree that the referenced service bulletins do not contain
the overhaul instructions for the horizontal stabilizer trim actuator.
Although the service bulletins do not list the detailed steps required
to overhaul the stabilizer trim actuator, the bulletins do reference
the appropriate CMM for accomplishing this task. We have made no change
to the supplemental NPRM in this regard.

Request for Addition of Indication

The Air Line Pilots Association (ALPA) recommends that there be a
clear indication to the operator when the primary load path has been
compromised to the point of loading the secondary load path, so that
corrective action can be taken immediately. The ALPA did not provide a
specific reason for, or data to support, its recommendation.
We acknowledge ALPA's request; however, we do not agree with the
need for this specific indication. The maintenance tasks and intervals
identified in the service bulletins, and proposed by this supplemental
NPRM, are intended to ensure proper operation and detect any
degradation of the stabilizer trim actuator ballscrew and ballnut,
without the need to provide a separate indication. Detection of any
degradation of the primary load path, as detailed in the service
bulletins, requires corrective action before further flight. The
proposed maintenance interval limits are intended to detect any
degradation of the primary load path in advance of loading the
secondary load path. We have made no change to the supplemental NPRM in
this regard.

Request To Notify Boeing of the Status of Original NPRM

Royal Brunei Airlines asks that Boeing be notified of the status of
the original NPRM if the FAA's intent is to mandate Service Bulletin
767-27A0194, Revision 2 (the original NPRM is identified in Revision 2
as related information); then operators can eliminate unnecessary
duplication of tasks. Royal Brunei Airlines states that the inspection
and lubrication of the horizontal trim actuator are already called out
in the relevant Boeing maintenance schedule. Royal Brunei Airlines adds
that the Boeing maintenance schedule is approved and mandated by its
local regulatory authority.
We acknowledge the commenter's request. However, it is not
necessary that Boeing be notified of the status of the original NPRM.
Boeing is aware that this supplemental NPRM to the original NPRM will
be issued to include the procedures specified in Revision 2 of the
referenced service bulletins. Boeing is also aware of the duplication
of tasks between the MPD and Service Bulletin 767-27A0194, Revision 2.
Although we agree that the inspection and lubrication tasks are
duplicated, the requirements in this AD take precedence over the
maintenance actions in the MPD. Boeing may, in a future revision to the
MPD, align the MPD with the requirements of the service bulletin. We
have made no change to the supplemental NPRM in this regard.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

Certain changes discussed above expand the scope of the original
NPRM; therefore, we have determined that it is necessary to reopen the
comment period to provide additional opportunity for public comment on
this supplemental NPRM.

Explanation of Change to Costs of Compliance

After the original NPRM was issued, we reviewed the figures we have
used over the past several years to calculate AD costs to operators. To
account for various inflationary costs in the airline industry, we find
it necessary to increase the labor rate used in these calculations from
$65 per work hour to $80 per work hour. The cost impact information,
below, reflects this increase in the specified hourly labor rate.

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.

Costs of Compliance

There are about 941 airplanes of the affected design in the
worldwide fleet. This supplemental NPRM would affect about 411
airplanes of U.S. registry. The following table provides the estimated
costs for U.S. operators to comply with this proposed AD, per cycle.

Estimated Costs
----------------------------------------------------------------------------------------------------------------
Number of U.S.-
Repetitive actions Work Average labor Cost per registered Fleet cost
hours rate per hour airplane airplanes
----------------------------------------------------------------------------------------------------------------
Detailed inspection................ 1 $80 $80 411 $32,880
Lubrication........................ 1 80 80 411 32,880
Freeplay measurement............... 3 80 240 411 98,640
====================================
----------------------------------------------------------------------------------------------------------------

[[Page 46579]]

The additional ballscrew-to-ballnut freeplay inspection would take
about 1 work hour per airplane, at an average labor rate of $80 per
work hour. Based on these figures, the estimated cost of the new
inspection on U.S. operators is $32,880, or $80 per airplane, per
inspection cycle.

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 proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 proposed
regulation:
1. Is not a ``significant regulatory action'' under Executive Order
12866;
2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979); and
3. 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 supplemental NPRM 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, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-22623; Directorate Identifier 2004-NM-
80-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by September
17, 2007.

Affected ADs

(b) None.

Applicability

Unsafe Condition

(d) This AD was prompted by a report of extensive corrosion of a
ballscrew in the horizontal stabilizer of a similar airplane model.
We are issuing this AD to prevent an undetected failure of the
primary load path for the ballscrew in the drive mechanism of the
horizontal stabilizer and subsequent wear and failure of the
secondary load path, which could lead to loss of control of the
horizontal stabilizer and consequent loss of control 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.

Repetitive Detailed Inspections/Lubrications/Freeplay Measurement/
Corrective Action

(f) Do all the applicable actions, including any applicable
corrective action, specified in Work Packages 1, 2, and 3 of the
Accomplishment Instructions of Boeing Service Bulletin 767-27A0194
(for Model 767-200, -300, and -300F series airplanes) or Boeing
Service Bulletin 767-27A0195 (for Model 767-400ER series airplanes),
both Revision 1, both dated July 21, 2005, or Revision 2, both dated
July 13, 2006, as applicable. Do the actions at the applicable
compliance time specified in Table 1 of paragraph 1.E.
``Compliance'' of the service bulletins; except, where the service
bulletins specify a compliance time relative to the original issue
date of the service bulletin, this AD requires compliance relative
to the effective date of this AD. Where the service bulletins
specify a compliance time relative to the delivery date of the
airplane, this AD requires compliance relative to the date of
issuance of the original standard airworthiness certificate or the
date of issuance of the original export certificate of
airworthiness. Do all applicable corrective actions before further
flight. Repeat the actions at the applicable repeat interval
specified in Table 1 of paragraph 1.E ``Compliance'' of the service
bulletins. As of the effective date of this AD only Revision 2 of
the service bulletin may be used.

Repetitive Ballscrew-to-Ballnut Freeplay Inspections

(g) For airplanes on which the A55001-22 lock equipment was used
to do the ballscrew-to-ballnut freeplay inspection, and the
maintenance records do not show that the tool was correctly adjusted
in accordance with Appendix A, step 1.E.3, of Boeing Service
Bulletin 767-27A0194 or 767-27A0195, both Revision 1, both dated
July 21, 2005: Do the ballscrew-to-ballnut freeplay inspection
specified in Work Package 3, including any applicable corrective
action, at the time specified in Table 1 of paragraph 1.E.
``Compliance'' of Boeing Service Bulletin 767-27A0194 or 767-
27A0195, both Revision 2, both dated July 13, 2006, as applicable.
Do all applicable corrective actions before further flight. Repeat
the inspection thereafter at the intervals specified in Table 1 of
paragraph 1.E ``Compliance'' of the service bulletins.

Previously Accomplished Actions

(h) For airplanes on which the drive mechanism of the horizontal
stabilizer was replaced before the effective date of this AD with a
drive mechanism that was not new or overhauled, and the detailed and
freeplay inspections were not accomplished in accordance with Boeing
Alert Service Bulletin 767-27A0194 or 767-27A0195, both dated August
21, 2003: Within 3,500 flight hours or 24 months after the effective
date of this AD, whichever is first, accomplish the inspections and
perform all applicable corrective actions before further flight in
accordance with Work Package 3 of the Accomplishment Instructions of
Boeing Service Bulletin 767-27A0194 or Boeing Service Bulletin 767-
27A0195, both Revision 1, both dated July 21, 2005; or Revision 2,
both dated July 13, 2006; as applicable. As of the effective date of
this AD only Revision 2 of the service bulletin may be used.
(i) For Model 767 airplanes that have line numbers 002 through
175 inclusive: Accomplishing the initial inspection, applicable
corrective action, and lubrication before the effective date of this
AD in accordance with Boeing Alert Service Bulletin 767-27A0185,
dated July 10, 2003; is considered acceptable for compliance with
the applicable actions required by paragraph (f) of this AD.

Note 1: Boeing Service Bulletins 767-27A0194 and 767-27A0195,
both Revision 2, both dated July 13, 2006, refer to the applicable
Boeing 767 Airplane Maintenance Manuals as additional sources of
service information for accomplishing the detailed inspections,
lubrications, freeplay measurements, and corrective action.

[[Page 46580]]

Parts Installation

(j) As of the effective date of this AD, no person may install
on any airplane a horizontal stabilizer trim actuator unless it is
new or has been overhauled as specified in Boeing Service Bulletins
767-27A0194 and 767-27A0195, both Revision 2, both dated July 13,
2006; or has been inspected, lubricated, and measured in accordance
with paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Seattle 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) 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 appropriate principal inspector (PI) in the FAA
Flight Standards District Office (FSDO), or lacking a PI, your local
FSDO.

Issued in Renton, Washington, on July 31, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-16424 Filed 8-20-07; 8:45 am]

BILLING CODE 4910-13-P