- Effective
- November 30, 1987
- Superseded by
- AD97-26-17
- Models
- IO-520 Series (all), TSIO-520 Series (all)
- Registered aircraft
- 13,648 matched by model
- Product
- Engine
- Amendment
- 39-5735
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed August 7, 2025.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 23 KB | c64668f1…61217b8 | FAA DRS (API key needed) |
On this page
The airworthiness directive
87-23-08 TELEDYNE CONTINENTAL MOTORS (TCM): Amendment 39-5735. Applies to TCM IO-520 and TSIO-520 series engines.
Compliance is required as indicated, unless already accomplished.
To prevent the installation of crankshafts with existing subsurface fatigue cracks which could result in crankshaft failure with resultant loss of engine power, at the next and every subsequent crankshaft removal from the engine case or installation of a replacement crankshaft, accomplish the following:
(a) Prior to installation in the engine, conduct an ultrasonic inspection in accordance with TCM Service Bulletin M87-5, Revision 1, dated May 25, 1987, and Crankshaft Ultrasonic Inspection Procedure, Form X30554, dated February 1981.
(b) If any cracks are found, replace crankshaft with serviceable crankshaft in accordance with TCM Service Bulletin M87-5, Revision 1, dated May 25, 1987.
(c) If no cracks are found, mark the propeller mounting flange in accordance with TCM Service BulletinM87-5, Revision 1, dated May 25, 1987. NOTE: Accomplishment of the ultrasonic inspection does not set aside any requirements for magnaflux or other inspections specified in TCM overhaul manuals.
Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Atlanta Aircraft Certification Office, Federal Aviation Administration, Central Region, 1669 Phoenix Parkway, Suite 210, Atlanta, Georgia 30349.
TCM Service Bulletin M87-5, Revision 1, dated May 25, 1987, identified and described in this document, is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). Copies may be obtained from Teledyne Continental Motors, P.O. Box 90, Mobile, Alabama 36601. Copies may be examined in the Regional Rules Docket, Office of the Regional Counsel, Room 311, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803 or at the Office of the Federal Register, 1100 LStreet NW, Room 8401, Washington, DC.
This amendment becomes effective November 30, 1987.
Registered aircraft · 13,648
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1918 | 1 |
|---|---|
| 1944 | 1 |
| 1946 | 2 |
| 1947 | 5 |
| 1948 | 7 |
| 1949 | 2 |
| 1950 | 7 |
| 1952 | 1 |
| 1953 | 2 |
| 1954 | 5 |
| 1955 | 7 |
| 1956 | 10 |
| 1957 | 4 |
| 1958 | 2 |
| 1959 | 3 |
| 1960 | 6 |
| 1961 | 10 |
| 1962 | 20 |
| 1963 | 44 |
| 1964 | 431 |
| 1965 | 331 |
| 1966 | 572 |
| 1967 | 446 |
| 1968 | 468 |
| 1969 | 386 |
| 1970 | 284 |
| 1971 | 236 |
| 1972 | 412 |
| 1973 | 600 |
| 1974 | 627 |
| 1975 | 781 |
| 1976 | 815 |
| 1977 | 846 |
| 1978 | 1,032 |
| 1979 | 1,072 |
| 1980 | 715 |
| 1981 | 660 |
| 1982 | 291 |
| 1983 | 147 |
| 1984 | 154 |
| 1985 | 127 |
| 1986 | 85 |
| 1987 | 84 |
| 1988 | 92 |
| 1989 | 64 |
| 1990 | 74 |
| 1991 | 60 |
| 1992 | 37 |
| 1993 | 40 |
| 1994 | 23 |
| 1995 | 8 |
| 1996 | 9 |
| 1997 | 8 |
| 1998 | 14 |
| 1999 | 14 |
| 2000 | 12 |
| 2001 | 15 |
| 2002 | 3 |
| 2003 | 2 |
| 2004 | 4 |
| 2005 | 1 |
| 2007 | 1 |
| 2015 | 1 |
| 2017 | 1 |
1,424 with no year recorded
By model
Aircraft
NTSB investigations that cite this AD · 1
Their narratives or probable cause name AD 87-23-08, often to say whether the aircraft complied with it.