ATP 3-21.51 — Subterranean Operations
ATP 3-21.51 governs doctrinal guidance and direction for brigade combat teams and subordinate elements conducting subterranean operations.
- Publication number: ATP 3-21.51
- Title: SUBTERRANEAN OPERATIONS
- Date: 11/01/2019
- Proponent: T2COM
- Status: ACTIVE
View ATP 3-21.51 on armypubs.army.mil
It covers subterranean environments, threats, facility operations, squad and individual techniques, enabling capabilities, and sustainment. The publication addresses planning and executing attacks, movement, contact reactions, casualty evacuation, resupply, and maintenance in subterranean operations.
Applies to: ATP 3-21.51 applies to the Active Army, Army National Guard/Army National Guard of the United States, and United States Army Reserve unless otherwise stated.
Topics covered
- Subterranean environments
- Underground facility attacks
- Squad and individual techniques
- CBRN and atmospheric threats
- Obstacle mitigation
- Casualty evacuation
- Resupply operations
Questions and answers
What sensors must be with the lead element during subterranean operations?
Oxygen sensors and CBRN detectors must be with the lead element at all times. (paragraph 5-37)
What should the clearing element do before breaching an internal door?
The clearing element should be prepared to conduct air monitoring for potential hazards at every internal door prior to conducting a breach. (paragraph 1-6)
Why is explosive breaching least preferred in a subterranean facility?
Explosive breaching is the least preferred method in a subterranean facility due to overpressure, shockwave propagation, air contamination, loss of visibility, and potential to collapse the passageway. (paragraph 6-70)
How narrow can small subterranean passageways be?
At most, small passageways only allow a single Soldier in the lead and may even require them to crawl or modify their equipment load to fit through the tight spaces. (paragraph 5-10)
What are trains in brigade combat team sustainment?
Trains are a grouping of personnel, vehicles, and equipment that provide sustainment to the battalion and subordinate companies of the BCT arrayed across the area of operations. (paragraph 7-55)