| AD Number | 73-20-03 | Status | Active |
| Effective Date | October 30, 1973 | Issue Date | Not specified |
| Docket Number | Unknown | Amendment | 39-1724 |
| Product Type | ["Aircraft"] | Product Subtype | ["Rotorcraft"] |
| CFR Part | --- - Part 39 | CFR Section | N/A |
| Citation | This information is not available. | ||
| Manufacturer(s) | Hiller Aviation Siam Hiller Holdings, Inc. |
| Model(s) | UH-12 UH-12A UH-12B UH-12C UH-12D UH-12E UH-12E-L |
73-20-03 HILLER AVIATION: Amdt. 39-1724. Applies to Hiller Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E Helicopters certificated in all categories.
Compliance required within the next 5 hours time in service after the effective date of this AD, unless already accomplished on receipt of the airmail AD dated September 6, 1973, and thereafter at intervals not to exceed 50 hours time in service from the last inspection.
To detect cracks in the main rotor hub P/N's 51437, 51437-6, 51437-7, 51437-8, 51437- 9, 51437-11, 51437-901, and 51437-11-911, accomplish the following: Conduct dye penetrant inspection of the main rotor hubs P/N's 51437, 51437-6, 51437-7, 51437-8, 51437-9, 51437-11, 51437-901, 51437-11-911, inside the hub in the area opposite the control rotor trunnion attachments. If cracks are found, replace with a new part before further flight and continue the 50 hour interval dye penetrant inspections. Report cracks found, model and serial number, and total time in service on the main rotor hub, to Chief, Aircraft Engineering Division, Federal Aviation Administration, Western Region, P.O. Box 92007, Worldway Postal Center, Los Angeles, California 90009. (Reporting approved by the Bureau of the Budget under B.O.B. No. 04-R0174).
This amendment is effective on October 30, 1973.