05-991. Airworthiness Directives; Boeing Model 777-200 and 777-300 Series 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 777-200 and -300 series airplanes. This proposed AD would require modification of the operational program software (OPS) of the air data inertial reference unit (ADIRU). This proposed AD is prompted by a report of the display of erroneous heading information to the pilot due to a defect in the OPS of the ADIRU. We are proposing this AD to prevent the display of erroneous heading information to the pilot, which could result in loss of the main sources of attitude data, consequent high pilot workload, and subsequent deviation from the intended flight path.

DATES:

We must receive comments on this proposed AD by March 7, 2005.

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.
• By 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.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-20081; the directorate identifier for this docket is 2004-NM-132-AD.

FOR FURTHER INFORMATION CONTACT:

Paul Feider, 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].

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 under ADDRESSES. Include “Docket No. FAA-2005-20081; Directorate Identifier 2004-NM-132-AD” in the subject line 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 submitted 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 website, 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 can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can 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 DMS receives them.

Discussion

We have received a report of the display of erroneous heading information to the pilot due to a defect in the operational program software (OPS) of the air data inertial reference unit (ADIRU) on certain Model 777 series airplanes. Investigation revealed a timing defect in the ADIRU Auto Navigation Realign Logic, which could potentially result in the use of a “stale” update, which would then produce incorrect heading information with a variable error magnitude. This condition, if not corrected, could result in loss of the main sources of attitude data, consequent high pilot workload, and subsequent deviation from the intended flight path.

Relevant Service Information

We have reviewed Boeing Service Bulletin 777-34A0082, Revision 1, dated December 19, 2002. The service bulletin describes procedures for modification of the OPS of the ADIRU. The modification includes installing new OPS in the flight compartment at the maintenance access terminal (MAT), or, as an option, replacing the hard drive for the existing OPS in the MAT and/or the Portable MAT. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

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. Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between the Proposed AD and Service Information.”

Difference Between the Proposed AD and Service information

Although the service information recommends accomplishing the modification “at the earliest opportunity when manpower, parts, and facilities are available,” we have determined that this imprecise compliance time would not address the identified unsafe condition in a timely manner. However, the manufacturer has recommended that the compliance time not exceed 6 months. In developing an appropriate compliance time for this AD, we considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the modification. In light of all of these factors, we find a compliance time of 6 months for completing the required modification to be warranted, in that it represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Costs of Compliance

There are about 409 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 130 airplanes of U.S. registry. The proposed actions would take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $8,450, or $65 per airplane.

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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.

This rulemaking is promulgated 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 proposed AD.

Regulatory Findings

We have determined that this proposed AD will not have federalism implications under Executive Order 13132. This proposed 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 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. 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20081; Directorate Identifier 2004-NM-132-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by March 7, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 777-200 and -300 series airplanes, certificated in any category; as listed in Boeing Service Bulletin 777-34A0082, Revision 1, dated December 19, 2002.

Unsafe Condition

(d) This AD was prompted by a report of the display of erroneous heading information to the pilot due to a defect in the operational program software (OPS) of the air data inertial reference unit (ADIRU). The Federal Aviation Administration is issuing this AD to prevent the display of erroneous heading information to the pilot, which could result in loss of the main sources of attitude data, consequent high pilot workload, and subsequent deviation from the intended flight path.

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.

Modification

(f) Within 6 months after the effective date of this AD: Modify the OPS of the ADIRU by doing the applicable actions specified in the Accomplishment Instructions of Boeing Service Bulletin 777-34A0082, Revision 1, dated December 19, 2002.

Alternative Methods of Compliance (AMOCs)

(g) 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.

Issued in Renton, Washington, on January 7, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.