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.
Aging has been described as the predominant cause of vertical ridges on the fingernails. Onychorrhexis is the medical term used to describe longitudinal ridges on the nails that often accompany brittle nails. In contrast to longitudinal ridges, Beau's lines are horizontal or transverse depressions in the nail that may be confused with nail ridging. These are caused by diseases that affect the entire body, including malnutrition, heart attack (myocardial infarction), severe infections, and metabolic disturbances, including poorly controlled diabetes.