61-03-04 LOCKHEED: Amdt. 244 Part 507 Federal Register January 27, 1961. Applies to All Model 1649A Aircraft.
Compliance required as indicated.
One of the following modifications to the vent system must be accomplished within 400 hours of time in service after the effective date of this directive.
(a) Modify only the right-hand vent float valve of the No. 7 tank (LAC P/N 634024- 3, Aero Supply Mfg. Co. P/N 22-1845-002) to a combination pressure relief and suction relief valve by removing the float assembly so that only the pressure and suction relief features remain operational. Replace the valve spring (P/N 22-0228-1) with spring (P/N 22-0337-1) having a higher cracking pressure.
(b) Replace only the original right-hand side valve assembly on No. 7 fuel tank with a new valve assembly LAC P/N 634024-5 (Aero Supply Mfg. Co. P/N 22-1845-003).
(Lockheed Letter dated August 22, 1960, directed to all 1649 operators completely covers the details of this modification.)This directive effective February 13, 1961.