47-21-05 NAVION: (Was Mandatory Note 4 of AD-782-3.) Applies to Serial Numbers NAV-4-11 Through 21 and 44 Through 47.
To be accomplished not later than August 1, 1947.
Replace the original propeller control with one that incorporates a positive friction lock in accordance with NAA Kit Drawing 145-89011.
(NAA Field Service Bulletin No. 5 covers this change.)