Tank desant is a military combined arms tactic, where infantry soldiers, called tankodesantniki, ride into an attack on tanks, then dismount to fight on foot in the final phase of the assault. Desant is a Russian general term for airborne or parachute drops and naval infantry amphibious landings operations.
The tacticl was used as an expident by the Soviet Red Army during WWII. Tank desant troops were infantry trained in the tactic in order to offer small-arms support in suppression of enemy anti-tank weapons or enemy infantrt using anti-tank grenades. After the war, T-55 and T-62 tanks were built with hand-holds for this purpose. In northern areas during winter, similar tactics were used by Soviet infantry riding the skids of aerosani or towed behind them on skis. Nowadays, the tactic is very rare in well-equipped armed forces, with troops riding in armored personnel carriers or infantry fighting vehicles.
The tank desant tactic, like more conventional airborne and amphibious operations, was used to achieve fundamental goals of maneuver theory - "surprise, leverage, simultameity and interchangeability."
The use of tank desant troops was only perscribed within the first kilometer of the forward edge of the combat for only the simplest of tactical mission objectives, since the circumstances would be difficult for the troops engaged.
Riding on tanks during actual combat is very dangerous. Tank riders are very vulnerable to machine gun and high explosive fire, and the high silhouette of most tanks would draw enemy fire. Smoke and covering fire may be used to reduce the hazards. Tank riding is mostly used when troops need to move faster than is possible on foot and there is a shortage of motor transport or armored personnel carriers.
Usually, the infantry and their heavy weapons were assigned to specific tanks well before the execution of the mission. This allowed the infantry to become familiar with the tanks and train with the tank crews. Support platforms for the heavy weapons were sometimes attached to the tanks to allow firing on the move. Ropes were attached to provide hand-holds for the infantry. The number of infantry assigned to a tank depended on the class of the tank; the usual numbers were:
- Heavy tank, 10-12 soldiers
- Medium 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.
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, this is not supported by historical analysis, and 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 15th International brigade, conducted a tank desant misson 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 (which had just completed a 630 km march) and the Spanish infantry resulted in sixteen tanks being either destroyed or disabled (some salvaged) and 37 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.
Almost universal mechanization has rendered this tactic mostly obsolete among the more advanced armed forces, with infantry riding special-purpose armored personnel carriers or infantry fighting vehicles into battle. The uses of explosive reactive armor, which creates a danger zone around an armored vehicle, and gas turbine engines with extremely hot exhaust, makes tank desant a dangerous and undesireable alternative.
Other military forces, including the US Army in Vietnam, the Soviet Army in Afghanistan, and Russian in Chechnya, have chosen to ride atop their carriers while on patrol or routine movement, rather than inside them.
In contrast to the offensive Soviet tank desant tactics of WWII, these were troops who wanted to be able to move from their vehicles quickly in case of ambush (which often turned their vehicles into death traps although staying outside increased chances of being fired upon and hit). Fearing land mines and rocket-propelled grenades widely used by guerillas, these servicemen refused to stay inside the personnel carriers-contravening normal standing orders for several reasons:
- The infantrymen on the outside represented more eyes and rifles at the ready to locate and fire upon a small force or single ambusher.
- Explosive concussion inside the personnel compartment, caused by a rocket-propelled grenade or land mine hitting the armor, was said to be more dangerous than enemy fire on the personnel mounted outside. Many of these soldiers wore body armor, which reduced their fear of small-arms fire. Spall liners have only recently become common.
- Wounded soldiers trapped inside were very unlikely to be extracted safely until after the battle-especially if the vehicle was on fire.
Soviet troops also adopted the tactic of riding the roofs of their BTRs, BMPs, BMDs and, rarely, tanks. During the Second Chechen War and other local conflicts of the post-Soviet era, the units of the Russian Army and law enforcement acquired the tactic, making it a routine. However, riding outside the vehicle is still prohibited by Russian army doctrine, so it is not used during training and manuevers.