Progress toward full all weather landing operation of transport aircraft is evaluated. Experience with Category II instrument approach operations in actual weather is reviewed. The disparity between the lagging implementation of ground facilities in the United States, and the extensive implementation of costly Category II airborne equipment is discussed.Actions needed to provide viable Category IIIa operations are examined, including discussion of procedures to aid in insuring integrity, and the need for implementing Category IIIa facilities in the United States. Implications of the proposed new landing guidance system and of possible independent landing monitors are also examined. Limitations of available weather surveys and a number of economic considerations are pointed out. Aggressive implementation of ground facilities is recommended.