02-16310. Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes. This proposal would require repetitive inspections to detect discrepancies of the drip shield and supports located above the rudder pedal mechanisms; corrective action, if necessary; and eventual modification of the drip shield, which would terminate the repetitive inspections. This action is necessary to prevent unrestrained drip shields from interfering with the rudder pedal mechanism, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by August 12, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-46-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-46-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

 

Technical Information: Clint Jones, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

Other Information: Sandi Carli, Airworthiness Directive Technical Editor/Writer; telephone [phone], fax [phone]. Questions or comments may also be sent via the Internet using the following address: [e-mail]. Questions or comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket 2002-NM-46-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket 2002-NM-46-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of two occurrences of a limitation of rudder pedal travel from the neutral position. Investigation revealed that a drip shield, located in the ceiling of the forward passenger compartment, became unrestrained and dropped down onto the rudder pedal mechanism, causing the limitation. The FAA has also received reports of evidence marks on drip shields, indicating interference contact with the rudder pedal mechanism. Analysis by the manufacturer indicates that an unrestrained drip shield can limit rudder pedal movement by up to 50% in one direction. (Movement in the opposite direction would be unaffected.) The limitation is caused by failure of the bonded drip shield supports, which would allow the drip shield to fall onto the rudder pedal mechanism. Limitation of rudder pedal movement could reduce the controllability of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001, which describes procedures for repetitive inspections of the drip shield and supports of the forward rudder quadrant to detect discrepancies (insufficient clearance from the components in the forward rudder quadrant, disbonded clip plates, and missing fasteners). Corrective actions include replacing missing fasteners and disbonded clip plates with new parts. The service bulletin also describes procedures for modifying the drip shield by installing blind rivets and changing the part numbers of the clip plates and drip shield, which would eliminate the need for the repetitive inspections. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin, except as discussed below.

Differences Between Proposed AD and Service Bulletin

The service bulletin recommends that the inspections be accomplished at regular “C-check” intervals. This proposed AD would require that the inspections be repeated every 3,000 flight hours (until the terminating action is accomplished). The FAA finds a 3,000-flight-hour interval appropriate for affected airplanes to continue to operate without compromising safety. Because C-check schedules vary among operators, such a nonspecific interval would provide no assurance that operators would follow the prescribed actions within the prescribed schedule.

Cost Impact

There are approximately 498 airplanes of the affected design in the worldwide fleet. The FAA estimates that 60 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be $3,600, or $60 per airplane, per inspection cycle.

It would take approximately 3 work hours per airplane to accomplish the proposed terminating action, at an average labor rate of $60 per work hour. The cost of required parts would be minimal. Based on these figures, the cost impact of the proposed terminating action on U.S. operators is estimated to be $10,800, or $180 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2002-NM-46-AD.

Applicability: Model 747-400 series airplanes, certificated in any category, as listed in Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously. To prevent unrestrained drip shields from interfering with the rudder pedal mechanism, which could result in reduced controllability of the airplane, accomplish the following:

Repetitive Inspections

(a) Within 1,200 flight hours after the effective date of this AD: Perform a general visual inspection of the drip shield and supports of the forward rudder quadrant to detect discrepancies (less than 0.50 inch clearance from the components in the forward rudder quadrant, disbonded clip plates, and missing fasteners), in accordance with Figure 1 of Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

(1) If no discrepancy is found: Repeat the inspection thereafter at least every 3,000 flight hours until the terminating action required by paragraph (b) of this AD has been accomplished.

(2) If any discrepancy is found during any inspection required by this paragraph: Before further flight, perform the specified corrective actions in accordance with Figure 1 of the service bulletin. Thereafter repeat the inspection at least every 3,000 flight hours until the terminating action required by paragraph (b) of this AD has been accomplished.

Note 3:

Accomplishment before the effective date of this AD of an inspection and applicable corrective actions in accordance with Boeing Service Bulletin 747-25A3271, dated April 12, 2001, is acceptable for compliance with the initial inspection requirement of paragraph (a) of this AD.

Terminating Action

(b) Within 2 years after the effective date of this AD, modify the drip shield by installing blind rivets in each clip plate and changing the part numbers of the clip plates and drip shield, in accordance with Figure 2 of Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.