54-19-01 PIPER: Applies to Models PA-18A and PA-18A Restricted Category Aircraft With Dusting Venturi, Up to and Including Serial Number 18-3752.
Compliance required not later than October 15, 1954.
There have been several instances of excessive CO concentration in the cockpit when the dusting venturi is used. Such contamination has serious adverse effects upon pilot reaction. To prevent CO from entering the cockpit, a new trim plate should be installed and a new brake line cover plate should be placed over the brake line where the line enters the bottom of the fuselage.
(Piper Service Letter No. 225, dated August 23, 1954, covers the same subject.)