# Proposed AD 94-ANE-44: Certain Textron Lycoming 320 and 360 Series Reciprocating Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-02-08
- Action: Supplemental notice of proposed rulemaking.
- Published: January 3, 1997, 62 FR 343
- Comments due: April 3, 1997
- Became: [AD 98-02-08](https://openairdocs.org/ad/98-02-08)
- Docket: 94-ANE-44
- FR document: 97-32
- Official PDF: https://openairdocs.org/files/sha256/5f/42/5f42b0537c7917692ce16b063ae60fe8c2067fe4fb9699cfd0568d5bc741d988 (from https://www.govinfo.gov/content/pkg/FR-1997-01-03/pdf/97-32.pdf)
- Federal Register: https://www.federalregister.gov/documents/1997/01/03/97-32/airworthiness-directives-certain-textron-lycoming-320-and-360-series-reciprocating-engines
- Page: https://openairdocs.org/proposed/94-ANE-44

## Summary

This notice revises an earlier proposed airworthiness directive (AD), which would have been applicable to all Textron Lycoming 235 series and 290 series, and certain 320 and 360 series reciprocating engines, that would have required initial and repetitive inspections of the crankshaft inner diameter (ID) for corrosion and cracks, and replacement of cracked crankshafts with a serviceable part. In addition, that proposed AD would have permitted operation of engines with crankshafts that were found to have corrosion pits but were free of cracks, provided repetitive inspections were performed by only certain qualified individuals until the next engine overhaul or 5 years after the initial inspection, whichever occurred first, at which time the proposed AD would have required those crankshafts with corrosion pits but no cracks to be replaced with serviceable crankshafts. That proposal was prompted by reports of crankshaft breakage originating from corrosion pits on the inside wall. This action revises the proposal by limiting the applicability of the proposed AD to only certain Textron Lycoming 320 and 360 series reciprocating engines, excluding additional engines installed in helicopters; permitting any certificated mechanic holding an airframe or powerplant rating to perform the Fluorescent Penetrant Inspection (FPI); permitting continued use of a pitted crankshaft as long as repetitive FPI inspections are performed; and deleting the five year limit on the use of crankshafts that are pitted but not cracked. Also, the FAA has received new cost information, and has revised the economic analysis with respect to the initial inspection time, the time to remove and replace crankshafts, the cost of the replacement crankshafts, and the cost for repetitive FPI inspections. Finally, this revised proposal introduces a public reporting survey to provide the FAA with a broader database on the condition of crankshafts when observed during the initial inspections. The actions specified by this proposed AD are intended to prevent crankshaft failure, which can result in engine failure, propeller separation, forced landing, and possible damage to the aircraft.

## Notices in this docket

- Nov 28, 1995: Notice of proposed rulemaking (NPRM). (first notice), FR document 95-28956, comments due Jan 29, 1996 (https://www.federalregister.gov/documents/1995/11/28/95-28956/airworthiness-directives-textron-lycoming-235-series-290-series-and-certain-320-and-360-series)
- Apr 8, 1996: Proposed rule; extension of comment period., FR document 96-8283, comments due Jun 7, 1996 (https://www.federalregister.gov/documents/1996/04/08/96-8283/airworthiness-directives-textron-lycoming-235-series-290-series-and-certain-320-and-360-series)
- Jan 3, 1997: Supplemental notice of proposed rulemaking., FR document 97-32, comments due Apr 3, 1997 (https://www.federalregister.gov/documents/1997/01/03/97-32/airworthiness-directives-certain-textron-lycoming-320-and-360-series-reciprocating-engines)

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