E6-1188. Airworthiness Directives; Boeing Model 757 Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 757 airplanes. This proposed AD would require installing a control wheel damper assembly at the first officer's drum bracket assembly and aileron quadrant beneath the flight deck floor in section 41; doing a functional test and adjustment of the new installation; and doing related investigative/corrective actions if necessary. For certain airplanes, this proposed AD would require doing an additional adjustment test of the re-located control wheel position sensor, and an operational test of the flight data recorder and the digital flight data acquisition unit. This proposed AD also would require installing vortex generators (vortilons) on the leading edge of the outboard main flap on certain airplanes. This proposed AD results from several reports that flightcrews experienced unintended roll oscillations during final approach, just before landing. We are proposing this AD to prevent unintended roll oscillations near touchdown, which could result in loss of directional control of the airplane, and consequent airplane damage and/or injury to flightcrew and passengers.

DATES:

We must receive comments on this proposed AD by March 17, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• 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: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., 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 the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

John Neff, Aerospace Engineer, Flight Test Branch, ANM-160S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-23734; Directorate Identifier 2005-NM-174-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, 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 proposed AD. 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 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 Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT 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 have received eleven confirmed reports that flightcrews on Boeing Model 757 airplanes experienced unintended roll oscillations during final approach, just before landing. One event resulted in a nose gear collapse after a hard landing; another event resulted in a tail strike during a landing that was aborted because of the oscillations. Of the eleven events that have been confirmed, three occurred with Flight Test personnel aboard, during flight-testing activities.

These roll oscillations occur when the pilot makes large, rapid movements of the control wheel, and the airplane does not respond as expected. Boeing has developed a damper for the control wheel that reduces the likelihood of these roll oscillations by providing resistive force to large, rapid control wheel movements that exceed a set value.

We have also received flight test data indicating that one potential cause of these unintended roll oscillations occurs when airflow over the outboard trailing edge flap separates due to the movement of the spoilers resulting from large control wheel inputs. Abrupt control wheel inputs to counteract the resulting roll can lead to roll oscillations of increasing magnitude. Boeing has developed vortex generators (vortilons) that create vortices over the flap surface and help to mitigate a sudden and premature airflow separation when the flaps are set in landing configuration and the spoilers forward of the flaps are deployed.

Unintended roll oscillations near touchdown, if not corrected, could result in loss of directional control of the airplane, and consequent airplane damage and/or injury to flightcrew and passengers.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 757-27A0146, dated October 14, 2004 (for Model 757-200, -200PF, and -200CB series airplanes); and Boeing Alert Service Bulletin 757-27A0147, dated October 14, 2004 (for Model 757-300 series airplanes). These service bulletins describe procedures for installing a control wheel damper assembly at the first officer's drum bracket assembly and aileron quadrant beneath the flight deck floor in section 41. This installation involves adding a new damper, bracket, crank arm, and control rod. The new damper bracket is installed at four existing holes on the drum bracket assembly. The service bulletins also describe procedures for doing a functional test and adjustment of the new installation, including doing any necessary related investigative and corrective actions and repeating the test and adjustment until all discrepancies are corrected. These service bulletins also describe procedures for sending a report when the applicable service bulletin is complete for each airplane.

We have also reviewed Boeing Alert Service Bulletin 757-57A0058, Revision 1, dated January 10, 2002 (for Model 757-200, -200PF and -200CB series airplanes). This service bulletin describes procedures for installing vortex generators (vortilons) on the leading edge of the outboard main flap. The service bulletin specifies that the vortex generators should be installed on both the left and right flaps at the same time. Installation of vortex generators on only one flap of an airplane may adversely affect the airplane's flight characteristics.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletins.”

Differences Between the Proposed AD and the Service Bulletins

Boeing Alert Service Bulletin 757-27A0146 and Boeing Alert Service Bulletin 757-27A0147 specify a compliance time of 36 months for installing a control wheel damper assembly. Boeing Alert Service Bulletin 757-57A0058, Revision 1, recommends installing the vortex generators at the next “heavy maintenance check.” This proposed AD would require doing all the actions within 24 months after the effective date of the proposed AD. In developing an appropriate compliance time for this proposed AD, we considered the manufacturer's recommendation, the degree of urgency associated with the subject unsafe condition, the probability of future occurrences, and the average utilization of the affected fleet. In light of all these factors we find that a 24-month compliance time represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Although the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0146 and Boeing Alert Service Bulletin 757-27A0147 describe procedures for submitting a sheet recording accomplishment of the service bulletin, this proposed AD would not require that action.

Although Boeing Alert Service Bulletin 757-27A0146 and Boeing Alert Service Bulletin 757-27A0147 specify that operators may contact the manufacturer if a just-installed (new) wheel damper does not function properly, this proposed AD would require operators to correct that condition according to a method approved by the FAA.

These differences have been coordinated with Boeing.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently investigating an additional modification that may further reduce or eliminate the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.

Costs of Compliance

There are about 1,036 airplanes of the affected design in the worldwide fleet and about 629 U.S.-registered airplanes. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. Not all of the required actions must be done on all U.S.-registered airplanes.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Install control wheel damper assembly, and do functional test (Model 757-200, -200PF, and -200CB series airplanes)	9 to 11	$65	$7,650 to $10,550	$8,235 to $11,265	578	$4,759,830 to $6,511,170.
Install control wheel damper assembly, and do functional test (Model 757-300 series airplanes)	15	65	$10,550	$11,525	51	$587,775.
Install vortex generators (Model 757-200, -200PF, and -200CB series airplanes)	10	65	$3,336	$3,986	527	$2,100,622.

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 proposed 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
• 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.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-23734; Directorate Identifier 2005-NM-174-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by March 17, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category; as identified in the applicable service bulletin or bulletins in Table 1 of this AD.

Table 1.—Boeing Service Bulletins

Boeing Alert Service Bulletin	Revision	Date	Model
757-27A0146	Original	October 14, 2004	757-200, -200PF, and -200CB.
757-27A0147	Original	October 14, 2004	757-300 series airplanes.
757-57A0058	1	January 10, 2002	757-200, -200PF, and -200CB.

Unsafe Condition

(d) This AD results from several reports that flightcrews experienced unintended roll oscillations during final approach, just before landing. We are issuing this AD to prevent unintended roll oscillations near touchdown, which could result in loss of directional control of the airplane, and consequent airplane damage and/or injury to flightcrew and passengers.

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.

Installations

(f) Within 24 months after the effective date of this AD, do the actions in paragraphs (f)(1) and (f)(2) of this AD, as applicable.

(1) For all airplanes: Install a control wheel damper assembly at the first officer's drum bracket assembly and aileron quadrant beneath the flight deck floor in section 41; and do all applicable functional and operational tests and adjustments of the new installation, and all applicable related investigative/corrective actions before further flight after the installation. Do all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0146, dated October 14, 2004 (for Model 757-200, -200PF, and -200CB series airplanes); and Boeing Alert Service Bulletin 757-27A0147, dated October 14, 2004 (for Model 757-300 series airplanes).

(2) For Model 757-200, -200PF, and -200CB series airplanes: Install vortex generators (vortilons) on the leading edge of the outboard main flap in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-57A0058, Revision 1, dated January 10, 2002.

Parts Installation

(g) As of the effective date of this AD, no person may install a damper bracket assembly part number (P/N) 251N1432-2, a bracket-sensor P/N 251N1430-2, or a crank arm P/N 251N1431-2, on any airplane.

Actions Accomplished in Accordance With Previous Revision of Service Bulletin

(h) Actions done before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 757-57-0058, dated March 9, 2000, are acceptable for compliance with the actions in paragraph (f)(2) of this AD.

No Reporting Required

(i) Although the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0146 and Boeing Alert Service Bulletin 757-27A0147 describe procedures for submitting a sheet recording accomplishment of the service bulletin, this AD does not require that action.

Alternative Methods of Compliance (AMOCs)

(j)(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) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on January 11, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.