tank, 8–10 soldiers Light tank, 5–6 soldiers Tank desant would be used in such a way as to ensure surprise, approaching during a snow storm or mist or employing either smoke grenades or a smoke screen prepared by sappers or laid down by artillery. History Today, tank desant is considered a wasteful and human-costly improvisation, which, in the opinion of some writers, was adopted by the Red Army because they failed to appreciate the problem of tank–infantry cooperation. However, there is evidence that tank desant was used as early as 1937 during the Spanish Civil War. On 13 October, during the Aragon Front advance in the area of the Fuentes de Ebro, the 1st Independent Tank Regiment (Republican Army), using BT-5 tanks attached to the XV International Brigade, conducted a tank desant mission with the attached 24th Infantry Battalion of the Spanish army (24ta de Voluntarios, commanded by Captain Aquilla). But lack of coordination and communication between the Soviet crews, who had just completed a march, and the Spanish infantry resulted in sixteen tanks being either destroyed or disabled (some salvaged) and 37 tank crewmen becoming casualties. Analysis of the Red Army's doctrine developed during the 1930s and documented in the 1936 Field Manual shows that the cavalry arm was expected to perform in the role of the supporting dismounted infantry and this was repeatedly displayed during the operations on the Eastern Front through use of the cavalry mechanized groups. The idea of using infantry tank desant was, however, retained in the 1942 Field Instructions for the infantry (battalion). Almost universal mechanization has, in theory, rendered this tactic mostly obsolete among the more advanced armed forces, with infantry riding special-purpose armoured personnel carriers or infantry fighting vehicles into battle. The use of active protection systems (especially hard kill types such as Arena) and/or explosive reactive armour, which creates a danger zone around an armoured vehicle by detonating an explosive charge when the tank suffers a serious hit, along with gas turbine engines in some tank designs, with their extremely hot exhaust, makes tank desant generally a dangerous and undesirable alternative. Modern usage Other military forces, including the United States Army in the Vietnam War, Sino Vietnamese War the Soviet Army in the Soviet–Afghan War, and the Russian Ground Forces in the First Chechen War, have chosen to ride atop their carriers while on patrol or routine movement, rather than inside