- Effective
- February 4, 1972
- Model
- 421B
- Data sheet
- TCDSA7CE
- Registered aircraft
- 225 matched by model
- Product
- Aircraft · Small airplane
- Amendment
- 39-1388
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 May 30, 2024.
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 | 19 KB | cc610c66…d190f92 | FAA DRS (API key needed) |
On this page
The airworthiness directive
72-03-04 CESSNA: Amdt. 39-1388. Applies to Model 421B (S/Ns 421B0001 through 421B0149) airplanes.
Compliance: Within the next 50 hours' time in service after the effective date of this AD, unless already accomplished.
To prevent blockage of the crankcase vent line by ice with subsequent engine failure due to loss of engine oil, accomplish the following modifications in accordance with Cessna Service Letter ME72-2, dated January 28, 1972, or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region:
A) Install a protective insulation sleeve over the crankcase vent line and scarf the vent line outlet to face aft.
B) Install propeller shaft seal retainer on each engine.
This amendment becomes effective February 4, 1972.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 225
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1970 | 6 |
|---|---|
| 1971 | 6 |
| 1972 | 19 |
| 1973 | 50 |
| 1974 | 57 |
| 1975 | 36 |
| 1993 | 1 |
50 with no year recorded