47-02-09 CULVER: (Was Mandatory Note 2 of AD-778-2.) Applies to Models V and V2 Aircraft Serial Numbers V-1 to V-150 Inclusive.
Compliance required prior to April 1, 1947.
Replace the brazed cabin heater valve box mounted on the firewall with a similar welded valve box which has fire resistant properties equivalent to the firewall.
(Culver Service Bulletin No. 7 covers this same subject.)