- Effective
- September 16, 1964
- Published
- September 15, 1964
- Issued
- September 1, 1964
- Models
- PA-23-250 (Navy UO-1), PA-30
- Registered aircraft
- 1,777 matched by model
- Product
- Aircraft · Small airplane
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 November 21, 2025.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
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On this page
The airworthiness directive
64-21-05 PIPER: Amdt. 809 Part 507 Federal Register September 15, 1964. Applies to Model PA-30 Aircraft Equipped With the Hartzell HC-E2YL-2B/7663-4 Propeller and Model PA-23-250 Aircraft Equipped With the Hartzell HC-E2YK-2RB/8465-7R Propeller.
Compliance required as indicated.
There have been several instances of propeller failure on the Piper PA-30 aircraft. The replacement of governor relief valve springs in accordance with Hartzell Service Bulletin No. 88 dated July 2, 1964, as amended July 8, 1964, has not eliminated these failures. The propeller installation on Piper Model PA-23-250 is similar in design and operation to that used on the Model PA-30. Accordingly, this AD is being made applicable to both Models PA-30 and PA-23-250. To preclude further failures, comply with the following:
(a) For aircraft having propellers previously serviced in accordance with Hartzell Service Bulletin No. 88 dated July 2, 1964, as amended July 8, 1964, service the propeller governors in accordance with Hartzell Service Bulletin No. 88A dated August 4, 1964, within 10 hours' time in service after the effective date of this AD.
(b) For aircraft having propellers which have not been previously serviced in accordance with Hartzell Service Bulletin No. 88A dated July 2, 1964, as amended July 8, 1964, service the propellers in accordance with these service bulletins and, in addition, in accordance with Hartzell Service Bulletin No. 88A dated August 4, 1964, within 10 hours' time in service after the effective date of this AD.
This supersedes AD 64-16-08.
This directive effective September 16, 1964.
Affected TCDS · 2
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 1,777
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1953 | 1 |
|---|---|
| 1957 | 1 |
| 1960 | 33 |
| 1961 | 13 |
| 1962 | 21 |
| 1963 | 101 |
| 1964 | 183 |
| 1965 | 145 |
| 1966 | 231 |
| 1967 | 134 |
| 1968 | 75 |
| 1969 | 151 |
| 1970 | 19 |
| 1971 | 24 |
| 1972 | 27 |
| 1973 | 44 |
| 1974 | 49 |
| 1975 | 36 |
| 1976 | 52 |
| 1977 | 35 |
| 1978 | 36 |
| 1979 | 46 |
| 1980 | 11 |
| 1981 | 10 |
| 1995 | 1 |
298 with no year recorded