02-15642. Airworthiness Directives: General Electric Company CF6-80A1/A3 and CF6-80C2A PMC Series Turbofan Engines

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-80A1/A3 and CF6-80C2A PMC series turbofan engines. This proposal would require performing either a Directional Pilot Valve (DPV) pressure switch moisture purge procedure and an operational check of the fan reverser or replacing the DPV assembly with a serviceable assembly and performing an operational check of the fan reverser. Thereafter, this AD would require one of these actions on a repetitive basis. This proposal is prompted by a review of fan reverser safety analyses resulting from the discovery of an undetectable failure mode of the DPV pressure switch on certain GE CF6-80C2A and CF6-80A engine models. The actions specified in the proposed AD are intended to prevent inadvertent fan reverser deployment, which, if it occurred in-flight, could result in loss of control of the airplane.

DATES:

Comments must be received by August 20, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-NE-09-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location, by appointment, between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. Comments may also be sent via the Internet using the following address: “[e-mail]”. Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in the proposed rule may be obtained from Middle River Aircraft Systems, Mail Point 46, 103 Chesapeake Park Plaza, Baltimore, MD, 21220-4295, telephone: [phone], fax: [phone]. This information may be examined, by appointment, at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT:

Ann C. Mollica, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park; Burlington, MA, 01803; telephone [phone]; fax [phone].

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 should 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.

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 Number 2002-NE-09-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRM's

Any person may obtain a copy of this NPRM by submitting a request to the FAA, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 2002-NE-09-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The FAA received a report of inadvertent thrust reverser deployment on a Pratt & Whitney powered Airbus Industrie A300-600 series airplane. Following that event, the FAA reviewed thrust reverser safety analyses on other make and model engines, including GE CF6-80A1/A3 and CF6-80C2A series turbofan engines. The thrust reverser is also known as the fan reverser on these engine models. A review of the thrust reverser actuation system (TRAS) component failure analyses and system safety analyses revealed that hidden failure modes involving the DPV assembly can exist, and an inadvertent deployment of the fan reverser could occur as a result.

The FAA had received reports of DPV pressure switch failures on several GE CF6-80 engines as early as 1998. Results of an investigation into the root cause of these events indicates that freezing of accumulated moisture within the switch prevented normal functioning of the switch. Under certain circumstances, ice formation within the pressure switch does not allow an internal spring to unload, and therefore results in a switch failure. When the pressure switch fails to actuate, it will erroneously indicate the TRAS is not pressurized, when it in fact is pressurized. These failures are not detectable in certain CF6-80A and CF6-80C2A engine models.

The DPV assembly controls the direction of the operation of the center drive unit when the TRAS is activated. High pressure downstream of the pressure regulating and shutoff valve (PRSOV) can be caused by auto restow, PRSOV open failures, or significant PRSOV leakage. The DPV pressure switch is used to detect PRSOV open failures and significant PRSOV leakage. If high pressure downstream of the PRSOV exists in combination with an undetected DPV pressure switch failure to actuate condition, an inadvertent deployment of the fan reverser could occur.

The FAA reviewed the system safety analysis with respect to the impact of the DPV pressure switch component failure rate and detectability of this failure mode. The FAA found that for certain CF6-80C2A and CF6-80A engine series, if this condition of switch freezing is not corrected, an inadvertent deployment could occur in-flight, and could result in loss of control of the airplane.

Manufacturer's Service Information

The FAA has reviewed and approved the technical contents of Middle River Aircraft Systems Alert Service Bulletin (ASB) CF6-80A1/A3 SB 78A4030, dated April 4, 2002, applicable to GE CF6-80A1/A3 series engines, and ASB CF6-80C2A PMC SB 78A1118, dated April 4, 2002, applicable to GE CF6-80C2A series engines, that describe procedures for DPV pressure switch moisture purges, and refer to applicable manuals which describe the replacement of the DPV assembly.

FAA's Determination of an Unsafe Condition and Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other GE CF6-80A1/A3 and CF6-80C2A PMC series turbofan engines of the same type design, this amendment is being proposed to prevent inadvertent fan reverser deployment. The proposed AD would require one of the following within 1,400 flight hours time-since-new (TSN) or 600 flight hours time in service (TIS) after the effective date of this AD, whichever occurs later:

(1) Performing the DPV pressure switch moisture purge procedure, and performing an operational check of the fan reverser; or

(2) Replacing the DPV assembly with a serviceable assembly and performing an operational check of the fan reverser.

Thereafter, this proposed AD would require one of these actions at intervals not to exceed 1,400 flight hours TIS since the last DPV pressure switch of the same type design moisture purge. The actions would be required to be done in accordance with the service bulletin described previously.

Economic Analysis

There are approximately 678 GE CF6-80A1/A3 and CF6-80C2A PMC series turbofan engines of the affected design in the worldwide fleet. The FAA estimates that 120 engines installed on airplanes of U.S. registry would be affected by this proposed AD. The FAA also estimates that it would take approximately 0.5 work hour per engine to purge the pressure switch and conduct an operational check and 0.5 work hour per engine to replace the DPV assembly and conduct an operational check. Approximately 5 percent of the fleet is expected to have the DPV assembly replaced instead of purging the DPV pressure switch each year. The average labor rate is $60 per work hour. Required parts to replace the DPV assembly would cost approximately $11,733 per engine.

At 1,400 hour intervals, based on an annual utilization rate of 1,600 hours, approximately 58 DPV purges or replacements will occur per year for CF6-80A1/A3 engines installed on US-operated A310 airplanes. Based on the 5 percent expectation, 55 purges will occur and three replacements will occur.

At 1,400 hour intervals, based on an annual utilization rate of 2,600 hours, approximately 130 DPV purges will occur per year for the CF6-80C2 PMC engines installed on US-operated A300-600 PMC airplanes. Based on the 5 percent expectation, 123 purges will occur and seven replacements will occur.

There are no US-operated A310 airplanes with CF6-80C2 PMC engines.

Based on these figures, the total yearly cost of the proposed AD on U.S. operators is estimated to be: $5,640 for labor and $117,330 for parts for a total cost of $122,970 per year.

Regulatory Analysis

This proposed rule does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposed rule.

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:

General Electric Company: Docket No. 2002-NE-09-AD.

Applicability

This airworthiness directive (AD) is applicable to General Electric Company (GE) CF6-80A1/A3 and CF6-80C2A PMC series turbofan engines. These engines are installed on, but not limited to Airbus Industrie A300-600 and A310 series airplanes.

Note 1:

This AD applies to each engine 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 engines 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 (j) 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

Compliance with this AD is required as indicated, unless already done.

To prevent inadvertent fan reverser deployment, which, if it occurred in-flight, could result in loss of control of the airplane, do the following:

GE CF6-80A1/A3 Series Engines

(a) For GE CF6-80A1/A3 series engines, perform one of the following no later than 1,400 flight hours time-since-new (TSN) or 600 flight hours time-in-service (TIS) after the effective date of this AD, whichever occurs later:

(1) Perform the directional pilot valve (DPV) pressure switch moisture purge, in accordance with Paragraph 3.C. of the Accomplishment Instructions of Middle River Aircraft Systems Alert Service Bulletin (ASB) CF6-80A1/A3 SB 78A4030, dated April 4, 2002, or

(2) Replace the DPV assembly with a serviceable assembly.

(b) After each purge or replacement done in accordance with paragraphs (a)(1) or (a)(2) of this AD, perform an operational check of the fan reverser in accordance with Paragraph 3.E. of the Accomplishment Instructions of ASB CF6-80A1/A3 SB 78A4030, dated April 4, 2002.

(c) Thereafter, for GE CF6-80A1/A3 series engines, at intervals not to exceed 1,400 hours TIS since the last pressure switch purge or replacement of the DPV assembly, perform one of the following:

(1) Perform the DPV pressure switch moisture purge, in accordance with Paragraph 3.C. of the Accomplishment Instructions of Middle River Aircraft Systems ASB CF6-80A1/A3 SB 78A4030, dated April 4, 2002, or

(2) Replace the DPV assembly with a serviceable assembly.

(d) After each purge or replacement done in accordance with paragraphs (c)(1) or (c)(2) of this AD, perform an operational check of the fan reverser in accordance with Paragraph 3.E. of the Accomplishment Instructions of ASB CF6-80A1/A3 SB 78A4030, dated April 4, 2002.

GE CF6-80C2A Series Engines

(e) For GE CF6-80C2A1/A2/A3/A5/A8 series engines, perform one of the following no later than 1,400 flight hours TSN or 600 flight hours TIS after the effective date of this AD, whichever occurs later:

(1) Perform the DPV pressure switch moisture purge, in accordance with Paragraph 3.C. of the Accomplishment Instructions of Middle River Aircraft Systems ASB CF6-80C2A PMC SB 78A1118, dated April 4, 2002, or

(2) Replace the DPV assembly with a serviceable assembly.

(f) After each purge or replacement done in accordance with paragraphs (e)(1) or (e)(2) of this AD, perform an operational check of the fan reverser, in accordance with Paragraph 3.E. of the Accomplishment Instructions ASB CF6-80C2A PMC SB 78A1118, dated April 4, 2002, 2002.

(g) Thereafter, for GE CF6-80C2A1/A2/A3/A5/A8 series engines, perform one of the following at intervals not to exceed 1,400 hours TIS since the last pressure switch purge or replacement of the DPV assembly:

(1) Perform the DPV pressure switch moisture purge, in accordance with Paragraph 3.C. of the Accomplishment Instructions of Middle River Aircraft Systems ASB CF6-80C2A PMC SB 78A1118, dated April 4, 2002, or

(2) Replace the DPV assembly with a serviceable assembly.

(h) After each purge or replacement done in accordance with paragraphs (g)(1) or (g)(2) of this AD, perform an operational check of the fan reverser, in accordance with Paragraph 3.E. of the Accomplishment Instructions of ASB CF6-80C2A PMC SB 78A1118, dated April 4, 2002.

Serviceable DPV Assembly

(i) For the purpose of this AD, a serviceable DPV assembly is an assembly that has:

(1) Accumulated zero time since new, or

(2) Passed the tests in the Middle River Aircraft Systems Component Maintenance Manual GEK 85007 (78-31-51), Revision No. 7 or later, Directional Pilot Solenoid Valve, Page Block 101, Testing and Troubleshooting, and that has zero flight hours TIS since passing the tests, or

(3) Been successfully purged according to paragraphs (a)(1), (c) (1), (e)(1) or (g)(1) of this AD immediately before installation on the fan reverser.

Alternative Methods of Compliance

(j) 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, Engine Certification Office (ECO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

Special Flight Permits

(k) Special flight permits may be issued in accordance with §§ 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 done.

Issued in Burlington, Massachusetts, on June 14, 2002.

Jay J. Pardee,

Manager, Engine and Propeller Directorate, Aircraft Certification Service.