PROPELLER CONTROLLING SYSTEM

FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: PROPELLER CONTROLLING SYSTEM SAIB: 2025-10 Date: September 26, 2025 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) advises owners and operators of Hamilton Sundstrand Corporation Model 247F-3 propellers of possible pitch change yoke fractures.

At this time, the airworthiness concern is isolated to Hamilton Sundstrand Model 247F-3 propellers installed on Xi'an Aircraft Industrial Corporation (Xi’an) Model MA60 airplanes. The Xi’an Model MA60 airplane is not an FAA type certificated product. This airworthiness concern is not an unsafe condition that would warrant an FAA airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39 for other airplanes with a 247F series propeller installed.

Background

Hamilton Sundstrand issued Service Bulletin 247F-61-66, dated October 31, 2018, to address pitch change yoke fractures on the Xi’an Model MA60 airplane experiencing elevated propeller vibrations. It is known that propeller actuators from the 247F-3 propeller system installed on Xi’an Model MA60 airplane were identified with pitch change yoke fractures, adjacent to the anti-torque arm slot. Hamilton Sundstrand’s root cause investigation concluded that, as integrated into the Xi’an Model MA60 airplane, the propeller pitch change yoke is subjected to oil temperatures that exceed the design requirements during certain operating conditions, which adversely affects the pitch change yoke, creating a potential for cracking. These out-of-specification operating conditions were verified by Hamilton Sundstrand during testing at the airplane manufacturer’s facility.

The Hamilton Sundstrand 247F-3 propeller system installed on the Xi’an Model MA60 airplane has an air-cooled oil cooler. All other 247F series propeller installations use a fuel-cooled oil cooler that does not result in known exceedances. The airworthiness concern is not present on other FAA type- certificated airplane installations of the Hamilton Sundstrand Model 247F series propellers.

Recommendation

The FAA recommends all owners and operators of Hamilton Sundstrand Model 247F-3 propellers installed on Xi’an Model MA60 airplanes incorporate the changes specified in Hamilton Sundstrand Service Bulletin 247F-61-66, dated October 31, 2018.

For Further Information Contact

David Bergeron, Aviation Safety Engineer, FAA; phone: (860) 386-1805; email: [email protected].

For Related Service Information Contact

Hamilton Sundstrand, A Collins Aerospace Company; website: collinsaerospace.com/support; email: [email protected].