Extracted From:
AC No. 43-16A
Alert No. 310
May 2004

During an inspection, the technician found numerous cracks in the lower firewall (P/N 0553031-5) left side zone 124. The cracks radiated from the lower battery mount and cowling mount brackets.

The submitter stated that he was aware of three additional like aircraft where the firewalls developed cracks in the same area.

A search of the FAA Service Difficulty Reporting Program data base contains 20 reports on Cessna 172R with firewall cracks. Most of the reports were generated while complying with Service Bulletin 98-53-02.

Part total time: 500 hours.