Cracking Up - NTSB Reports

Prior to installing an overhauled fuel cell, it was found to contain a large quantity of sawdust-like particles. Further inspection revealed the foam filling the fuel reservoir was breaking down. The older cells reservoir foam insert was compatible with 100/130 fuel. However, 100LL causes the foam to break down into fine particles that get trapped in filters and screens. This problem is addressed in service bulletin (SB) number 2109 which replaces the old style foam (p/n 369200157) with a product that is suitable for use with 100LL.

Editorial Staff

Tuesday, May 20, 2008 at 12:00 AM ET

Verified

Key Takeaways:

Beech B55 Barons face fuel cell foam disintegration when using 100LL fuel, leading to filter blockages, with Service Bulletin 2109 addressing the issue by providing compatible foam.
Superior (Continental IO-520-F) engines have experienced cracks in cylinders #3 and #4, originating at the exhaust valve seat.
Cessna 150/152 aircraft show a history of cracked, broken, or corroded aft fin attach fittings (p/n 0431009, especially the -3 variant), necessitating continued maintenance awareness due to high-stress operational use.
Continental IO-240-B17B engines have reported instances of jammed fuel pump mixture control shafts, leading to lean mixture conditions.