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AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Notice of proposed rulemaking (NPRM).
SUMMARY:
The FAA proposes to supersede Airworthiness Directive (AD) 2023-20-03, which applies to certain Austro Engine GmbH Model E4 and E4P engines. AD 2023-20-03 requires repetitive engine oil analysis for aluminum content outside the acceptable limits and, if necessary, replacement of the pistons, piston rings, con-rods assembly, and crankcase or, as an alternative, replacement of the engine core. Since the FAA issued AD 2023-20-03, the manufacturer identified errors in the lists of affected engines and provided updated information, which prompted this proposed AD. This proposed AD would retain the requirements of AD 2023-20-03, add compliance times for additional affected engine serial numbers, and remove certain engine serial numbers from the applicability of the existing AD. The FAA is proposing this AD to address the unsafe condition on these products.
DATES:
The FAA must receive comments on this NPRM by November 14, 2024.
ADDRESSES:
You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
- Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
- Fax: (202) 493-2251.
- Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
- Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2024-2318; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, the mandatory continuing airworthiness information (MCAI) any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
- For Austro Engine GmbH material identified in this proposed AD, contact Austro Engine GmbH, Rudolf-Diesel-Strasse 11, A-2700 Weiner Neustadt, Austria; phone: +43 2622 23000; website:austroengine.at.
- You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call (817) 222-5110.
FOR FURTHER INFORMATION CONTACT:
Morton Lee, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (860) 386-1791; email: morton.y.lee@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2024-2318; Project Identifier MCAI-2023-00981-E” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.
Confidential Business Information
CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Morton Lee, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background
The FAA issued AD 2023-20-03, Amendment 39-22562 (88 FR 76104, November 6, 2023) (AD 2023-20-03), for certain Austro Engine GmbH Model E4 and E4P engines. AD 2023-20-03 was prompted by an MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued EASA AD 2022-0240R1, dated December 15, 2022 (EASA AD 2022-0240R1), to address reports of piston failures.
AD 2023-20-03 requires repetitive engine oil analysis for aluminum content outside the acceptable limits and, if necessary, replacement of the pistons, piston rings, con-rods assembly, and crankcase or as an alternative, replacement of the engine core. The FAA issued AD 2023-20-03 to prevent piston failure, which could result in loss of oil, loss of engine power, and reduced control of the airplane.
Actions Since AD 2023-20-03 Was Issued
Since the FAA issued AD 2023-20-03, EASA superseded EASA AD 2022-0240R1 and issued EASA AD 2023-0163, dated August 18, 2023 (EASA AD 2023-0163) (also referred to as the MCAI). The MCAI states that a manufacturer investigation into reports of piston failures determined that certain batches of pistons were manufactured with a dimensional deviation in the piston pin bore and in the piston diameter, which could cause piston failure, with consequent loss of oil, loss of engine power, and reduced control of the airplane. To address the unsafe condition, EASA issued EASA AD 2022-0240, dated December 6, 2022, to specify repetitive oil analyses and replacement of the pistons, piston rings, con-rods assembly, and crankcase, or as an alternative, replacement of the engine core. EASA AD 2022-0240 also prohibited release to service of an airplane until receipt of the results for each oil analysis.
Since EASA AD 2022-0240 was issued, the manufacturer determined that aluminum levels outside of the acceptable limits would be found during the first oil analysis and would be unlikely to be found during subsequent oil analyses. As a result, EASA revised EASA AD 2022-0240 and issued EASA AD 2022-0240R1 to allow release to service of airplanes for a limited number of flight hours immediately after the second and subsequent oil samples are taken for analyses.
Since EASA AD 2022-0240R1 was issued, the manufacturer identified errors in the lists of affected engine serial numbers in the service information and issued Mandatory Service Bulletin No. MSB-E4-039/2, Revision 2, dated July 31, 2023, to revise the list of affected engine serial numbers, which prompted EASA to supersede EASA AD 2022-0240R1 with EASA AD 2023-0163, dated August 18, 2023. Since EASA issued EASA AD 2023-0163, the manufacturer revised the service information again and issued Mandatory Service Bulletin No. MSB-E4-039/3, Revision 3, dated November 22, 2023, to amend the labor efforts section.
You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2024-2318.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Austro Engine GmbH Mandatory Service Bulletin No. MSB-E4-039/3, Revision 3, dated November 22, 2023, which identifies affected engine serial numbers and specifies procedures for oil analysis and replacement of the pistons, piston rings, con-rods assembly, crankcase, and engine core.
This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
FAA's Determination
These products have been approved by the aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI and material referenced above. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would retain all of the requirements of AD 2023-20-03. This proposed AD would also add compliance times for additional affected engine serial numbers and remove certain engine serial numbers from the applicability of the existing AD, as specified in the material already described.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 357 engines installed on aircraft of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
Estimated Costs
| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
|---|---|---|---|---|
| Oil analysis | 1 work-hour × $85 per hour = $85 | $0 | $85 | $30,345 |
On-Condition Costs
| Action | Labor cost | Parts cost | Cost per product |
|---|---|---|---|
| Replace engine core | 35 work-hours × $85 per hour = $2,975 | $15,524 | $18,499 |
| Replace pistons, piston rings, and con-rod assembly | 65 work-hours × $85 per hour = $5,525 | 2,216 | 7,741 |
| Replace pistons, piston rings, con-rod assembly, and crankcase | 75 work-hours × $85 per hour = $6,375 | 4,141 | 10,516 |
Table 1 to Paragraph ( g )(1)—Oil Analysis for All Affected Engines
| Engine group | Compliance time | Interval |
|---|---|---|
| Group 1 and Group 3 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Within 15 flight hours (FHs) from December 11, 2023 (the effective date of AD 2023-20-03) | Before exceeding 50 FHs since last oil analysis. |
| Group 1 and Group 3 engines that have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Within 15 FHs from the effective date of this AD | Before exceeding 50 FHs since last oil analysis. |
| Group 2 and Group 4 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Within 25 FHs from December 11, 2023 (the effective date of AD 2023-20-03) | Before exceeding 100 FHs since last oil analysis. |
| Group 2 and Group 4 engines that have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Within 25 FHs from the effective date of this AD | Before exceeding 100 FHs since last oil analysis. |
Table 2 to Paragraph ( g )(1)—Affected ESNs Not Included in AD 2023-20-03
| Engine group | ESN | ESN | ESN | ESN |
|---|---|---|---|---|
| Group 1 | E4-A-06367 | E4-A-06248 | ||
| Group 2 | E4-C-06249 | E4P-C-06185 | ||
| Group 3 | E4-A-05072 | E4-A-05074 | E4-A-05075 | E4-A-05078 |
| Group 3 | E4-A-05079 | E4-A-05080 | E4-A-05081 | E4-A-05082 |
| Group 3 | E4-A-05083 | E4-A-05084 | E4-A-05085 | E4-A-05086 |
| Group 3 | E4-A-05087 | |||
| Group 4 | E4-C-00559 | E4-C-05089 | E4-C-05090 | E4-C-05091 |
| Group 4 | E4-C-05092 | E4-C-05093 | E4-C-05094 | E4-C-05096 |
| Group 4 | E4-C-05098 | E4-C-05099 | E4-C-05100 | E4-C-05101 |
| Group 4 | E4-C-05102 | E4-C-05103 | E4-C-05104 | E4-C-05105 |
| Group 4 | E4-C-05106 | E4-C-05107 | E4-C-05108 | E4-C-05109 |
| Group 4 | E4-C-05110 | E4-C-05111 | E4P-C-06073 |
Table 3 to Paragraph ( g )(5)—Replacement for Group 3 and 4 Engines
| Engine group | Compliance time |
|---|---|
| Group 3 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Before exceeding 900 FHs since new, or within 15 FHs after December 11, 2023 (the effective date of AD 2023-20-03), whichever occurs later. |
| Group 3 engines that have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Before exceeding 900 FHs since new, or within 15 FHs after the effective date of this AD, whichever occurs later |
| Group 4 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Before exceeding 1,000 FHs since new, or within 25 FHs after December 11, 2023 (the effective date of AD 2023-20-03), whichever occurs later. |
| Group 4 engines that have an ESN identified in Table 2 to paragraph (g)(1) of this AD | Before exceeding 1,000 FHs since new, or within 25 FHs after the effective date of this AD, whichever occurs later. |