Applies To Some Piper And Mooney GA Airplanes

The FAA has put out a Special Airworthiness Information Bulletin (SAIB) concerning Hartzell Propeller spinner assemblies, part numbers (P/N) 835-54(P) or 835-58(P) that may be installed on  Piper PA-24, Piper PA-28R-180, Piper PA-28R-200, and Mooney M20 airplanes. The SAIB does not include the Mooney M20(J). The SAIB warns of the potential for cracking of the spinner dome which could lead to failure and liberation of the spinner.

The FAA has have received reports of Hartzell spinners, P/N 835-54(P) and 835-58(P), installed on the aircraft listed above which have developed cracks. These cracks will propagate with use, eventually leading to spinner liberation and damage to the airplane. The reported failures have caused in-flight vibrations resulting in premature landings. Many of these spinners were newly manufactured and had a relatively low amount of time-in-service. Hartzell Propeller conducted testing and analysis on the spinner failures and noted that during some flight operations a resonant vibratory condition was present. Hartzell Propeller has developed a replacement spinner configuration that mitigates the vibratory environment. There are approximately 380 airplanes affected by this condition. Spinners installed on Mooney M20 (J) airplanes in accordance with Hartzell STC SA02414CH-D are not affected by this condition because they do not have the subject spinner assembly installed.

If a crack on the spinner is discovered during pre-flight inspection, the FAA recommends replacement of the spinner before further flight. If a crack is not found, then, replacement of the spinner assembly is recommended within 50 flight hours.

Guidance may be found Hartzell Service Bulletin HC-SB-61-311, Revision 5, dated December 13, 2011 and Hartzell Alert Service Bulletin HC-ASB-61-332, Revision 5, dated December 13, 2011, or later FAA approved revisions. The airworthiness concern is not an unsafe condition that would warrant airworthiness directive action at this time, the agency said.

FMI: SAIB