In 1971 VR-30 joined the Jet Age with two North American CT-39 Saberliners for high-speed executive airlift. In May 1973 the squadron received the first of four C-9B Skytrain II's to further improve its logistics support capability.
Vertical ridges can also be caused by nail injury and certain diseases, including rheumatoid arthritis, according to Rich. If, instead of a series of ridges, there's a single vertical streak, cautions Krant, this could be a sign of a tumor growing at the root of the nail.
Causes of Fingernail Ridges, Pitting and Curved Nails. 1  Longitudinal ridges (running from the cuticle to the free edge of the nail) may be due to aging and not a sign of any disease.  Nail beading, where the nail loses its smooth curvature, is also a normal part of aging.