On April 16, 2001, we issued AD 2001-08-15, Amendment 39-12192 (66 FR 21067, April 27, 2001). That AD requires initial and repetitive inspections for bearing material contamination of the engine oil system. That AD was prompted by reports of rapid failures of the No. 1 bearing. That AD also allows as terminating action to the repetitive inspections, incorporation of Embraer Service Bulletin (SB) 145-79-0001, dated April 24, 1998. That SB installs an electrical jumper in an airplane electrical connector, which adds a second function to the Oil Impending Bypass advisory message, on the Engine Indication and Crew Alerting System (EICAS). After incorporation of the SB, this message can either represent that there is an oil impending bypass, or that the magnetic chip detector plug has collected enough ferrous metal to indicate possible initiation of bearing failure. That condition, if not corrected, could result in smoke in the cabin and an uncommanded in-flight engine shutdown.
Actions Since AD 2001-08-15 Was Issued
Since that AD was issued, the manufacturer has introduced several turbine design changes, each of which sufficiently reduces the axial load on the No. 1 bearing, to virtually eliminate the potentially unsafe condition of rapid, undetected bearing failure. The design changes include:
Modifying the current high pressure (HP)-to-low pressure (LP) seal assembly, part number (P/N) 23068183, with a large geometric rear seal diameter, and remarking it to new P/N 23073953. This modified seal assembly adjusts interstage turbine cavity pressure and effectively reduces the axial load on the No. 1 bearing.
Introducing new HP-to-LP seal assemblies, P/Ns 23074463, 23074729, 23076526, and 23077397, with a smaller geometric rear seal diameter. These new seal assemblies also reduce the axial load on the No. 1 bearing.
Relevant Service Information
We have reviewed and approved the technical contents of the following RR service bulletins (SBs) and Embraer SB:
RR SB AE 3007A-79-034, dated May 14, 2002, which provides procedures for inspecting for bearing material contamination of the engine oil system by reviewing the maintenance page on the cockpit Multi Function Display.
RR SB AE 3007A-72-199, Revision 3, dated May 13, 2002, which provides procedures to modify the HP-to-LP seal assembly, P/N 23068183, and remark seal assembly to P/N 23073953.
RR SB AE 3007A-72-213, Revision 1, dated May 13, 2002, which provides procedures to install new design HP-to-LP seal assembly, P/N 23074729.
RR SB AE 3007A-72-213, Revision 2, dated November 20, 2003, which provides procedures to install new design HP- to-LP seal assembly, P/N 23077397.
RR SB AE 3007A-72-248, dated July 29, 2003, which provides procedures to install new design HP-to-LP seal assembly, P/N 23074463.
RR SB AE 3007A-72-263, Revision 1, dated March 4, 2003, which provides procedures to modify the HP-to-LP seal assembly, P/N 23074729, and remark seal assembly to P/N 23076526.
RR SB AE 3007A-72-284, dated October 16, 2003, which provides procedures to modify the HP-to-LP seal assembly, P/N 23074729 or P/N 23076526, and remark seal assembly to P/N 23077397.
Embraer SB 145-79-0001, dated April 24, 1998, which provides procedures to modify the airplane wiring so that the oil impending bypass message will be displayed in the cockpit when the primary engine magnetic chip detector captures debris.
FAA's Determination and Requirements of This AD
The unsafe condition described previously is likely to exist or develop on other RR AE 3007A, AE 3007A1/1, AE 3007A1/2, AE 3007A1, AE 3007A1/3, AE 3007A1P, and AE 3007A3 turbofan engines of the same type design. We are issuing this AD to prevent the rapid failure of the No. 1 bearing, which could result in smoke in the cabin and an uncommanded in-flight engine shutdown. This AD requires initial and repetitive inspections for bearing material contamination ofthe engine oil system, and adds terminating actions to the repetitive inspections required by this AD. Six of the seven terminating actions listed, eliminate the unsafe condition by installing new or reworked parts, and one terminating action eliminates the unsafe condition by installing an electrical jumper in an airplane electrical connector, which adds a second function to the Oil Impending Bypass advisory message, on the EICAS. You must do these actions in accordance with the service information described previously.
FAA's Determination of the Effective Date
Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Changes to 14 CFR Part 39--Effect on the AD
On July 10, 2002, we issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs our AD system. This regulation now includes material that relates to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "AD Docket No. 2000-NE-29-AD" in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it; we will date-stamp your postcard and mail it back to you. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it. If a person contacts us through a nonwritten communication, and that contact relates to a substantive part of this AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend the AD in light of those comments.
We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications with you. You may get more information about plain language at http://www.faa.gov/language and http://www .plainlanguage.gov.
Examining the AD Docket
You may examine the AD Docket (including any comments and service information), by appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See ADDRESSES for location.
Regulatory Findings
We 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.
For the reasons discussed above, I certify that the 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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include "AD Docket No. 2000-NE-29-AD" in your request.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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. The FAA amends 39.13 by adding the following new airworthiness directive: