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CFR Citation: 14 CFR Part 39

Docket ID: [Docket No. FAA-2008-0585; Directorate Identifier 2008-NM-027-AD]

RIN ID: RIN 2120-AA64

NOTICE: PROPOSED RULES

ACTION: Airworthiness Directives:

DOCUMENT ACTION: Notice of proposed rulemaking (NPRM).

SUBJECT CATEGORY: Airworthiness Directives; Boeing Model 747SP Series Airplanes

DATES: We must receive comments on this proposed AD by July 7, 2008.

DOCUMENT SUMMARY: We propose to adopt a new airworthiness directive (AD) for all Boeing Model 747SP series airplanes. This proposed AD would require repetitive lubrication of the rudder tab hinges and repetitive replacement of the rudder tab control rods. This proposed AD results from reports of freeplayinduced vibration of the control surfaces on Boeing Model 727, 737, 757, and 767 airplanes. We are proposing this AD to prevent damage to the control surface structure during flight, which could result in loss of control of the airplane.

SUMMARY: Boeing Model 747SP Series Airplanes,

SUPPLEMENTAL INFORMATION

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include ``Docket No. FAA20080585; Directorate Identifier 2008NM027AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed 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 proposed AD.

Discussion

We have received reports of freeplayinduced vibration of control surfaces on Boeing Model 727, 737, 757, and 767 airplanes. Excessive wear of components or interfaces allows excessive freeplay of the control surfaces and can cause unacceptable airframe vibration during flight. The potential for vibration of the control surface should be avoided because the point of transition from vibration to divergent flutter is unknown. Divergent flutter can cause damage to the control surface structure during flight. This condition, if not corrected, could result in loss of control of the airplane.

Although there have been no reports of freeplayinduced vibration of the rudder tabs for Model 747SP airplanes, the affected control surfaces on Boeing Model 727, 737, 757, and 767 airplanes and Boeing Model 747SP airplanes are similar in design. Therefore, all of these models might be subject to the identified unsafe condition. Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 74727 2447, dated January 17, 2008. The service bulletin describes procedures for repetitive lubrication of the rudder tab
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hinges, and repetitive replacement of the rudder tab control rods. For airplanes on which BMS 333 grease is used to lubricate the rudder tab hinges, the compliance time for the first lubrication is within 9 months after the date on the service bulletin, and the repetitive interval is not to exceed 18 months thereafter. For airplanes on which BMS 333 grease is not used to lubricate the rudder tab hinges, the compliance time for the first lubrication is 9 months after the date on the service bulletin, and the repetitive interval is not to exceed 9 months thereafter. The compliance time for all airplanes for the first replacement of the rudder tab control rods is within 6,000 flight hours after the date on the service bulletin, and the repetitive interval is not to exceed 8,000 flight hours thereafter.

Other Relevant Rulemaking

The following ADs resulted from reports of freeplayinduced vibration of control surfaces on Boeing Model 727, 737, 757, and 767 airplanes.

On March 30, 2006, we issued AD 20060723 (amendment 3914550, 71 FR 18194, April 11, 2006) for all Boeing Model 757 airplanes. That AD requires repetitive measurements of the freeplay of each of the three power control units that move the rudder; repetitive lubrication of rudder components; and corrective actions if necessary. That AD resulted from a report of freeplayinduced vibration of the rudder. That AD explained that the potential for vibration of the control surface should be avoided because the point of transition from vibration to divergent flutter is unknown. We issued that AD to prevent excessive vibration of the airframe during flight, which could result in divergent flutter and loss of control of the airplane.

On June 15, 2006, we issued AD 20061316 (amendment 3914669, 71 FR 36481, June 27, 2006) for certain Boeing Model 727 airplanes. That AD requires repetitive measurements of the freeplay of the left and right outboard aileron balance tabs and of the upper and lower rudder tabs, and related investigative/corrective actions if necessary. That AD also requires repetitive lubrication of the hinge bearings and rod end bearings of the outboard aileron balance tabs. That AD resulted from reports of freeplayinduced vibration of the outboard aileron balance tabs and rudder tabs. We issued that AD to prevent excessive vibration of the airframe during flight, which could result in divergent flutter and loss of control of the airplane.

On September 28, 2006, we issued AD 20062101 (amendment 3914784, 71 FR 59368, October 10, 2006) for all Boeing Model 737 airplanes. That AD requires repetitive measurement of the freeplay of both aileron balance tabs; repetitive lubrication of the aileron balance tab hinge bearings and rod end bearings; and related investigative and corrective actions if necessary. That AD resulted from reports of freeplayinduced vibration of the aileron balance tab. That AD also explained that the potential for vibration of the control surface should be avoided because the point of transition from vibration to divergent flutter is unknown. We issued that AD to prevent excessive vibration of the airframe during flight, which could result in loss of control of the airplane.

On November 16, 2007, we issued AD 20072408 (amendment 3915274, 72 FR 67236, November 28, 2007), for all Boeing Model 767 airplanes. That AD requires repetitive measurements of the rudder freeplay and the elevator freeplay for each of the power control actuators that move the rudder and elevator, corrective and related investigative actions if necessary, and repetitive lubrications of the rudder and elevator components. For some airplanes, that AD also requires related concurrent actions. That AD also explained that the potential for vibration of the control surface should be avoided because the point of transition from vibration to divergent flutter is unknown. We issued that AD to prevent excessive vibration of the airframe during flight, which could result in loss of control of the airplane.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the(se) same type design(s). This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD would affect 7 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. The average labor rate is $80 per work hour.
Estimated Costs Work
Action hours Parts Cost per product Fleet cost Lubrication....................... 2 None................. $160, per cycle...... $1,120, per cycle. Replacement....................... 16 $39,511.............. $40,791, per cycle... $285,537, per 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 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 this 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,
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on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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 39AIRWORTHINESS 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 FAA amends Sec. 39.13 by adding the following new AD: Boeing: Docket No. FAA20080585; Directorate Identifier 2008NM 027AD.
Comments Due Date
(a) We must receive comments by July 7, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to all Boeing Model 747SP series airplanes. Unsafe Condition
(d) This AD results from reports of freeplayinduced vibration of the control surfaces on Boeing Model 727, 737, 757, and 767 airplanes. We are issuing this AD to prevent damage to the control surface structure during flight, which could result in loss of control of the airplane.
Compliance
(e) Comply with this AD within the compliance times specified, unless already done.
Repetitive Lubrication and Replacement
(f) At the applicable compliance time listed in Paragraph 1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin 74727 2447, dated January 17, 2008, lubricate the rudder tab hinges and replace the rudder tab control rods with new control rods. Repeat the lubrication and replacement thereafter at the applicable repeat interval listed in paragraph 1.E., ``Compliance,'' of the service bulletin. Do all actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 74727 2447, dated January 17, 2008. Where Boeing Special Attention Service Bulletin 747272447, dated January 17, 2008, specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Kathleen Arrigotti, Aerospace Engineer, Airframe Branch, ANM120S, 1601 Lind Avenue, SW., Renton, Washington 980573356; telephone (425) 9176426; fax (425) 9176590; has the authority to approve AMOCs for this AD, if requested using 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.
(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 an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who 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.

Issued in Renton, Washington, on May 8, 2008.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. E811567 Filed 52208; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Kathleen Arrigotti, Aerospace Engineer, Airframe Branch, ANM120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057 3356; telephone (425) 9176426; fax (425) 9176590.