Airworthiness Directive · Amendment 39-21815 · Propeller hub section
Hoffmann GmbH & Co. KG Propellers
Superseded. A later AD replaced this one: AD 2022-21-13. Comply with the one in force.
This AD applies to all Hoffmann GmbH & Co. KG model HO-V 72 propellers.
The FAA is superseding Airworthiness Directive (AD) 2020-25-05 for all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 2020-25-05 required amending the existing aircraft flight manual (AFM) with abnormal propeller vibration instructions. AD 2020-25-05 also required visual inspection and non-destructive test (NDT) inspection of the propeller hub and, depending on the results of the inspections, replacement of the propeller hub with a part eligible for installation. AD 2020-25-05 also required replacement of the propeller hub before exceeding 30 years since the date of manufacture. This AD was prompted by reports of cracks at different positions on two affected propeller hubs and subsequent manufacturer revision of the service information, which showed that the 30-year life limit of the propeller hub is no longer needed. This AD requires amending the existing AFM by inserting abnormal propeller vibration instructions, visual inspection and NDT inspection of the propeller hub and, depending on the results of the inspections, replacement of the propeller hub with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Before the next flight after December 22, 2020 (the effective date of AD 2020-25-05), amend the existing aircraft flight manual by inserting the procedure: “Abnormal propeller vibrations: As applicable, reduce engine RPM.”
(2) Before the next flight after the effective date of this AD, and thereafter, before the next flight after any flight where abnormal propeller vibrations have been experienced, visually inspect propeller hub HO-V 72 () ()-()-() for cracks using paragraph 2.1 of Hoffmann Propeller GmbH & Co. KG Service Bulletin SB E53, Rev. D, dated February 18, 2021 (the SB).
(3) Within 20 flight hours after the effective date of this AD, perform a non-destructive test (NDT) inspection of propeller hub HO-V 72 () ()-()-() using paragraph 2.3 of the SB.
(4) During each overhaul of propeller hub HO-V 72 () ()-()-() after the effective date of this AD, perform an NDT inspection using paragraph 2.3 of the SB.
(5) If, during any inspection required by paragraph (g)(2), (3), or (4) of this AD, any crack is detected, replace propeller hub HO-V 72 () ()-()-() with a part eligible for installation.
For the purpose of this AD, a “part eligible for installation” is a propeller hub HO-V 72 () ()-()-() with zero hours time since new or a propeller hub HO-V 72 () ()-()-() that has passed an NDT inspection using paragraph 2.3 of the SB.
(1) Sending the propeller to Hoffmann for investigation, as contained in paragraph 2.1 of the SB, is not required by this AD.
(2) Reporting propeller hubs with cracks to Hoffmann, as contained in paragraph 2.3 of the SB, is not required by this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Propellers
