AD 2000-18-06

This amendment adopts a new airworthiness directive (AD), that is applicable to Allison Engine Company AE 3007A and AE 3007C series turbofan engines with certain full authority digital electronic controls (FADEC's), listed by hardware serial number (SN), installed. This action requires inspections of installed FADEC's before further flight to be sure that no more than one engine with suspect FADEC's is installed on the same airplane, and eventual replacement of all of the suspect FADEC's with serviceable FADEC's. This amendment is prompted by reports of uncommanded in-flight shutdowns of engines. The actions specified in this AD are intended to prevent an uncommanded in-flight engine shutdown and the potential for an in-flight dual-engine shutdown caused by a potential hardware failure mode in some AE 3007 series FADEC's.

Final rule; request for comments.

2000-18-06 Allison Engine Company: Amendment 39-11891. Docket 2000-NE-33-AD.

Applicability
This AD is applicable to Allison Engine Company Models AE 3007A, AE 3007A1/1, AE 3007A1/2, AE 3007A1, AE 3007A1/3, AE 3007A1P, AE 3007A3, and AE 3007C turbofan engines with full authority digital electronic controls (FADEC's) that have the following hardware serial numbers (SN's) installed:

Engine Model
FADEC Hardware SN
AE 3007C
BX55758, BX55760, BX55761, BX55763 through BX55765, BX55767, and BX61001 through BX61069, unless the FADEC has been repaired and marked as provided in paragraphs (f) and (g) of this AD.
AE 3007A, AE 3007A1/1, AE 3007A1/2, AE 3007A1/3, AE 3007A1, AE 3007A1P, AE 3007A3
BX56348, BX56361 through BX56364, BX56374, BX56376, BX56392 through BX56395, BX59006, BX59007, BX59013, BX59014, BX59041, BX59050, BX59062, BX59064 through BX59066, BX59075 through BX59078, BX60000 through BX60145, BX60172 through BX60239, BX60265 through BX60287, BX60301, BX60303, BX60311, BX60381 through BX60384, unless the FADEC has been repaired and marked as provided in paragraphs (f) and (g) of this AD.

These engines are installed on, but not limited to Embraer Model EMB-145, EMB-145ER, EMB-145MR, EMB-145LR, EMB-135ER, EMB-135LR, and Cessna 750 airplanes.

Note 1: This airworthiness directive (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 (h) 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 below, unless already done. To prevent an uncommanded in-flight engine shutdown and the potential for an in-flight dual-engine shutdown, do the following:

Inspection for FADEC Serial Number and Removal of FADEC's
(a) Before further flight, inspect the FADEC for a SN that is listed in "Applicability" of this AD to be sure that no airplane has more than one engine with FADEC's that have suspect hardware SN's. The engine may have two FADEC's that have suspect hardware SN's.

(b) If more than one engine per airplane is found with a FADEC that has a suspect hardware SN, remove the FADEC so there is only one engine per airplane with a FADEC that has a suspect hardware SN.

(c) Removed suspect FADEC's may be returned to local stock.

(d) The suspect FADEC's may be installed on another airplane as long as the requirements of paragraphs (a) and (e) of this AD are met.

Replacement of all Suspect FADEC's
(e) Replace all FADEC's that have suspect hardware SN's with serviceable FADEC's within 3 months after the effective date of this AD.

(f) After 3 months from the effective date of this AD, do not install a FADEC that has a hardware SN listed in "Applicability" of this AD on any engine unless the FADEC hardware has been repaired and the modification tag on the FADEC is marked with TR1 day/month. For example, a repair that was accomplished on September 25, 2000, will show as TR1 25/09.

Definition of a Serviceable FADEC
(g) For the purpose of this AD, a serviceable FADEC is a FADEC that does not have a hardware SN listed in "Applicability" of this AD, unless the FADEC with the suspect hardware SN has been modified using Rolls-Royce (RR) service bulletin (SB) AE 3007A-73-042, Revision 1, dated August 23, 2000; or RR SB AE 3007C-73-024, Revision 1, dated August 23, 2000.

Alternative Methods of Compliance
(h) An alternative method of compliance (AMOC) or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Chicago Aircraft Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Chicago Aircraft Certification Office.

Note 2: Information concerning the existence of any approved AMOC with this airworthiness directive, may be obtained from the Chicago Aircraft Certification Office.

Special Flight Permit
(i) 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 accomplished.

Effective Date
(j) This amendment becomes effective on September 22, 2000.

The Allison Engine Company has notified the FAA that there is a quality problem with FADEC's that have certain hardware SN's installed on AE 3007 series engines. This can lead to an uncommanded engine shutdown in flight, the inability of the FADECs to switch from one channel to another channel (channel A to B), or the inability to shutdown an engine. Three uncommanded in-flight engine shutdowns, eight events in which the FADEC channels could not be changed, and three events in which the engine could not be shut down prompted these actions. Allison Engine Company has determined that these events resulted from a quality problem with the internal power supply transistor TR1 in FADEC's with certain hardware SN's. This condition, if not corrected, could also result in an uncommanded in-flight engine shutdown and the potential for an in-flight dual-engine shutdown caused by a potential hardware failure mode in some AE 3007 series FADEC's.

The compliance times of this AD were chosen based on the risk analysis of a dual-engine shutdown. These compliance times assure the desired level of fleet safety of this action as a function of airplane utilization variations throughout the fleet.

Determination of an Unsafe Condition
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to require inspection of FADEC's for suspect hardware SN's and, if necessary, removal of that FADEC before further flight. This is to be sure that no more than one engine with FADEC's that have suspect hardware SN's is installed on each airplane.

This AD will also require the replacement of all FADEC's that have suspect hardware SN's with serviceable FADEC's within 3 months after the effective date of this AD.

Immediate Adoption
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2000-NE-33-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
This proposed rule does not have federalism implications, as defined in Executive Order No. 13132, because it would not have a substantial direct effect on the States, on the relationship between the national government and theStates, 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.

Federalism Assessment
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and 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 it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from 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.
Adoption of the Amendment
Accordingly, pursuant to 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. Section 39-13 is amended by adding a new airworthiness directive, Amendment 39-11891, to read as follows: