Background \n\n\tOn April 29, 2005, we issued AD 2005-10-03, amendment 39-14080 (70 FR 24703, May 11, 2005), for certain Boeing Model 777-200 and "300 series airplanes. That AD requires modification of the operational program software (OPS) of the air data inertial reference unit (ADIRU) from software version part number (P/N) 3470-HNC-100-03 to software version P/N 3475-HNC-100-06 or 3474-HNC-100-07. That AD resulted from a report of the display of erroneous heading information to the pilot due to a defect in the OPS of the ADIRU. We issued that 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. \n\nActions Since Issuance of Previous AD \n\n\tOn August 29, 2005, we issued emergency AD 2005-18-51, which applies to all Boeing Model 777 airplanes. That AD resulted from a recent report ofa significant nose-up pitch event on a Boeing Model 777-200 series airplane while climbing through 36,000 feet altitude. The flightcrew disconnected the autopilot and stabilized the airplane, during which time the airplane climbed above 41,000 feet, decelerated to a minimum speed of 158 knots, and activated the stick shaker. A review of the flight data recorder shows there were abrupt and persistent errors in the outputs of the ADIRU. These errors were caused by the OPS using data from faulted (failed) sensors. This problem exists in all software versions after P/N 3470-HNC-100-03, beginning with P/N 3477-HNC-100-04 approved in 1998 and including the versions mandated by AD 2005-10-03. While these versions have been installed on many airplanes before we issued AD 2005-10-03, they had not caused an incident until recently, and the problem was therefore unknown until then. OPS using data from faulted sensors, if not corrected, could result in anomalies of the fly-by-wire primary flightcontrol, autopilot, auto-throttle, pilot display, and auto-brake systems, which could result in high pilot workload, deviation from the intended flight path, and possible loss of control of the airplane. \n\nRelevant Service Information \n\n\tWe have reviewed Boeing Alert Service Bulletin 777-34A0137, dated August 26, 2005. The service bulletin describes procedures for installing OPS, P/N 3470-HNC-100-03, in the ADIRU. \n\n\tWe also have reviewed Boeing 777 Operations Manual Bulletin (OMB) CS3-3093, dated August 26, 2005, which describes operating instructions to inform the flightcrew of possible heading errors following on-ground automatic realignment of the ADIRU with the OPS, P/N 3470-HNC-100-03, installed. \n\n\tIn addition, we have reviewed Boeing 777 OMB CS3-3155, dated August 26, 2005, which describes operating instructions to inform the flightcrew of potential drift angle discrepancies on the primary flight display and the navigation display with the OPS, P/N 3470-HNC-100-03, installed. \n\nFAA's Determination and Requirements of This AD \n\n\tSince the unsafe conditions described previously are likely to exist or develop on other airplanes of the same type design, we issued emergency AD 2005-18-51 to supersede AD 2005-10-03. This new AD requires accomplishing the actions specified in Boeing Alert Service Bulletin 777-34A0137, described previously. Because these actions reintroduce the unsafe condition identified in AD 2005-10-03, this new AD also requires revising the Limitation section of the Airplane Flight Manual by inserting a copy of Boeing 777 OMBs CS3-3093 and CS3-3155, described previously. \n\nInterim Action \n\n\tWe consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD and AD 2005-10-03. Once this modification is developed, approved, and available, we may consider additional rulemaking \n\nFAA's Determination of the Effective Date \n\n\tWe found that immediate corrective action was required; therefore, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual notices issued on August 29, 2005, to all known U.S. owners and operators of Boeing Model 777 airplanes. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to Sec. 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons. \n\nComments Invited \n\n\tThis AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2005- 22252; Directorate Identifier 2005-NM-182-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments. \n\n\tWe 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 AD. Using the search function of our docket 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 can review the 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. \n\nExamining the Dockets \n\n\tYou 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 (800) 647- 5227) 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. \n\nAuthority for This Rulemaking \n\n\tTitle 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. \n\n\tWe 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 proceduresthe 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. \n\nRegulatory Findings \n\n\tWe have determined that this AD will not have federalism implications under Executive Order 13132. This 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. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If this emergency regulation is later deemed significant under DOT Regulatory Policies and Procedures, we will prepare a final regulatory evaluation and place it in the AD Docket. See the ADDRESSES section for a location to examine the regulatory evaluation, if filed. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing amendment 39-14080 (70 FR 24703, May 11, 2005) and adding the following new airworthiness directive (AD):