Localizer type directional aid Localizer type directional aid A localizer type directional aid (LDA) is a type of localizer-based instrument approach to an airport. It is used in places where, due to terrain and other factors, the localizer antenna array is not aligned with the runway it serves. In these cases, the localizer antenna array may be offset (i.e. pointed or aimed) in such a way that the approach course it projects no longer lies along the extended runway centerline (which is the norm for non-offset and non-LDA localizer systems). If the angle of offset is thirty degrees or less, the facility is classified
Type 97 90 mm Infantry Mortar Type 97 90 mm Infantry Mortar The Type 97 90 mm Infantry Mortar was a simplified version of the Japanese Type 94 90 mm Infantry Mortar. The Type 97 designation was given to this gun as it was accepted in the year 2597 of the Japanese calendar (1937). The Type 90-mm mortar is a Stokes-Brandt type mortar similar in appearance to the US 81-mm mortar, M1 and the Japanese Type 97 81 mm piece. It is believed that the 90 mm weapon has been introduced later than its model number would imply, as a captured specimen was marked "Model 97