Defile
Operations at the NTC
by
LTC Michael Shields, Brigade S3 Trainer, NTC
(This
is the second of two articles by LTC Shields on the difficulties light task
forces (TFs) experience when conducting truck infiltration missions at the
National Training Center (NTC). His first article, published in CALL's CTC
Quarterly Bulletin, 3d Qtr, FY 99, No. 99-14,
Oct
99, "Truck Infiltration (Assault) Planning in a Heavy/Light Scenario," presents
tactics, techniques and procedures (TTP) for planning and executing such a
mission. This second article goes hand in hand with the first. It discusses
one of the drills that is often a major factor in determining the success or
failure of a unit's infiltration mission at the NTC - defile operations.)
ISSUE:
Light
task forces (TFs) are challenged when planning for, and executing, defile operations.
DISCUSSION:
1.
Figure
1
and
Figure
2
illustrate
a common scenario observed at the NTC when TFs attempt to conduct a defile
drill.
Note
that the TF began entering the defile at approximately 0430 (limited visibility
because of darkness). At approximately 0721 (daylight), the TF ordered the
company/team (CO/TM) to pull back. Four plus hours were consumed trying to
get through the defile. The CO/TM was rendered combat ineffective.
2.
Given the restricted terrain at the NTC, it is inevitable that infantry task
forces (sometimes armor) conduct defile operations. Defile drills are combined
arms operations whether conducted at company or battalion level. Defile clearing
operations are conducted in three phases (reference FM
71-1, Tank
and Mechanized Infantry Company Team):
a.
The approach phase focuses on moving combat power into restricted terrain and
positioning forces to begin clearing operations. b.
The clearing phase begins as the infantry assaults through the restricted terrain.
The infantry must clear both sides of the defile and along the ridgelines and
walls of the defile. c.
The securing phase begins when the defile has been cleared. The TF must secure
the far side of the defile beyond the restricted terrain. Securing the far
side often includes continuing the attack to destroy enemy forces covering
the exit of the defile and establishing support-by-fire (SBF) positions on
the far side to protect follow-on forces assuming the fight. 3.
This article addresses planning considerations by phase and the graphics show
"a way" to help visualize the narrative. The task organization depicted in
the scenario is an example and not prescriptive in nature. Ideally, reconnaissance
forces identify a bypass so the TF is not required to clear enemy-occupied
restricted terrain. This article focuses on the worst-case scenario, where
a TF has to fight through a defile.
RECOMMENDATIONS:
1.
Approach
Phase.
a.
Critical to success in the defile is positioning reconnaissance forces throughout
the restricted terrain to identify the composition, disposition, and strength
of enemy forces including obstacles. Consider the use of terrain products (such
as Terra Base) to assist in visualizing the defile. b.
Once on the far side, reconnaissance forces establish surveillance positions
or observation posts (OPs) to observe enemy counterattack avenues of approach.
(1) These reconnaissance forces are generally not the TF scouts.
TF scouts typically conduct reconnaissance missions vicinity of the TF objective.
The reconnaissance assets must be pulled from within the TF. Possible assets
include infantry (such as squads/teams), forward observer (FO) teams, or engineer
reconnaissance teams (ERTs).
(2) Stinger teams should be considered in the reconnaissance plan
if the air threat dictates.
(3) The TF mortars should be positioned to provide fire support
to the reconnaissance forces.
c.
Infantry squads conduct a reconnaissance on both sides of the defile (see Figure
3).
A squad from Team B (TF advanced guard) reconnoiters (recons) the north side
of the defile, and a rifle squad from A Company recons the south side of the
defile. ERTs conduct a route reconnaissance of both passes. The ERT in the
south does not continue beyond the tank ditch. The obstacle in the north is
identified as a surface-laid mine/wire obstacle and can be breached with TF
assets. d.
The TF commander elects to attack through the northern pass. Critical friendly
zones (CFZs) are activated covering the northern pass and the TF main body.
No fire areas (NFAs) cover reconnaissance assets. The TF mortars position to
cover the reconnaissance forces and have sensor zone coverage. The sensor zone
is a force protection measure to protect the TF mortars when firing from within
the CFZ. Reconnaissance assets conduct long-range surveillance and observation
of enemy counterattack routes, and the engineers maintain surveillance of the
obstacles. e.
The TF then positions forces to prepare for clearing operations. Truck-mounted
and mechanized infantry move forward to dismount points while the advanced
guard (initial TF maneuvering element (ME)) overwatches their move. The role
of the advanced guard is to destroy enemy forces overwatching the entrance
to the defile and to fix enemy forces trying to reposition or reinforce (isolate
the defile) (also consider integration of attack aviation). Mortars, air defense,
and combat service support assets move into position. f.
The TF is operating two tactical command posts with the S3 moving with the
advanced guard and the battalion commander with the main body (or some variation).
The TF commander must position his command and control facilities to maintain
situational awareness and control fire and maneuver. g.
The main body remains back, out of direct fire and observation by enemy forces
securing the defile. Direct fire control measures (terrain or threat-based)
are established to prevent the fratricide of friendly forces as they approach
the defile and begin clearing operations, and NFAs are established to protect
reconnaissance forces on the far side of the defile. The TF should consider
and apply surface danger zones (SDZs) and minimum safe distances (MSDs) for
indirect fires when developing the fire plan. (Clearance of fires and direct
fire control are extremely difficult when conducting defile operations. A good
litmus test is to ask yourself if you would execute your plan in a live-fire
exercise). h.
Reconnaissance forces continue to conduct surveillance, ensuring they move
out of SDZs/MSD areas of the TF (see Figure
4).
i.
The TF begins positioning forces to set the conditions for the clearing phase.
(1) Team B (-) occupies support-by-fire (SBF) position B1 and orients
fires between target reference points (TRPs) 1 and 2, to destroy enemy forces
on OBJ Cat, to prevent the enemy from placing effective direct fires on the
infantry forces as they move forward to dismount and occupy assault positions.
TM B's infantrymen are consolidated at company level to clear the north side
of the defile.
(2) One mechanized platoon (minus infantry) occupies SBF B1A in
the south, orienting fires between TRPs 2 and 3, to destroy counterattacking
enemy forces, to protect the southern flank of the TF.
(3) A Company, mounted on 5-ton trucks, moves forward to a dismount
point to clear the south side of the defile.
(4) The ERTs move back to link up with the engineer platoon (out
of SDZs/MSDs).
(5) The artillery battery is firing WP to obscure the TFs movement
to the dismount point and assault positions.
(6) The mortar platoon is suppressing enemy positions. The focus
of fires is on OBJ Cat.
(7) The remainder of the TF (on trucks) is in a security halt, dispersed,
and out of direct fire range of the enemy. The TF is covered by an active CFZ.
j.
The approach phase ends when the infantry (clearing force) is prepared to conduct
the assault through the defile. The TF plans and executes suppression and/or
obscuration fires (S.O.S.R.) during the approach phase to help set conditions
for the clearing phase. 2.
Clearing
Phase.
a.
The clearing phase begins as the infantry assaults through the restricted terrain.
The Vee formation (not the "school solution") is uniquely suited for defile
operations at TF level; however, companies may move using some other formation,
such as echelon or wedge, based on the enemy situation. The Vee formation facilitates
clearing north and south of the defile with heavy forces supporting along the
mounted avenue of approach. b.
The infantry should clear from the top down and orient on an objective(s).
The TF scheme of maneuver must prevent simultaneous clearing by two companies
abreast because of the high risk of fratricide as they both clear from the
top down and shoot back at each other. The TF should bound companies forward
(in the Vee) and develop a scheme of fires (including direct) to shift/lift
fires as units approach SDZs (consider the use of restrictive fire lines (RFLs)
and TRPs) and MSDs. Use phase lines as minimum safe lines to prevent movement
within a SDZ or MSD for indirect fire. c.
Heavy force employment considerations include the following:
(1) Bradley Fighting Vehicles (BFVs) can elevate the 25mm main gun
higher than the M1 tank's 120mm main gun (+60 degrees versus +20 degrees for
the tank).
(2) Armor-piercing, fin-stabilizing, discarding SABOT (APFSDS) rounds
from the 25mm are less restrictive than the 120mm SABOT petals.
(3) The M1 tank can be used to accomplish specific missions within
its capabilities such as destroying armor, bunkers, and fortifications. Use
of tanks or Bradleys should be situation dependent.
(4) Consider employing the Javelin, TOW, and AT-4 to destroy fighting
positions/bunkers.
(5) Engineers should move with the infantry to provide a manual
breaching capability. This allows the infantry to focus on the enemy threat.
Heavy engineers with the CO/TM should be augmented with mobility assets, such
as an AVLM, ACE, or a tank with plow if a mechanical breach requirement is
identified during the planning process. The TF may have to ask the brigade
combat team (BCT) for additional assets. The M1 tank plow can clear a four-meter
width to provide a limited sub-surface and surface minefield clearing capability
(18" spoil requirement IAW NTC ROE).
d.
The clearing phase ends when the defile has been cleared to the far side. Figures
5A, B, C and D depict "a way" to work through the fire control challenges of
a defile drill. As the figures illustrating the clearing phase progress, previously
used graphics no longer pertinent are deleted to aid in clarity.
(1) The TF has designated two march objectives to facilitate controlling
maneuver and fires. The defile is subdivided it into OBJs Cat and Dog. OBJs
Cat and Dog are split by RFL 1, which runs down the main road. Each OBJ is
further subdivided into OBJs North and South.
(2) The TF designates terrain-based fire control measures to control
direct fires. Additional fire control measures have been established and are
discussed in the clearing phase.
e.
Figure
5A.
For
the purpose of this article, B Company refers to infantry from Team B. Both
infantry companies are in assault positions vicinity PL Birch, the final coordinating
line. As B Company prepares to cross PL Birch, indirect fires lift off OBJ
Cat North and shift to OBJ Cat South (the focus of fires) and OBJ Dog North.
B Company crossing PL Birch (FCL) is the trigger for Team B and A Company to
shift all direct fires south of the RFL 1 (vicinity TRP 2-OBJ Cat South). Both
companies are weapons tight. A Company remains in an assault position short
of PL Birch until OBJ Cat North has been cleared. Once B Company has cleared
OBJ Cat North, they occupy SBF B2 and orient fires on TRP 2 (OBJ Cat South).
Team B (-) lifts fires off of OBJ Cat (weapons hold). A Company (the TF main
effort) crosses PL Birch (RFL 2 in effect for the BFV platoon in the south)
and assaults to clear OBJ Cat South (from east to west). The focus of indirect
fires shifts to OBJ Dog North. B Company (weapons tight) shifts fires in support
of A Company's assault based on procedural control measures. With RFL 1 in
effect, B Company cannot engage OBJ Cat South without coordination with A Company
and the TF (establishing HQ). B Company prepares to continue the attack to
OBJ Dog North. f.
Figure
5B.
Once
OBJ Cat South is clear, A Company occupies SBF A1 and orients fires on TRP
5 (OBJ Dog South). B Company begins movement toward PL Maple and the engineers
conduct a manual (or mechanical) breach and create a lane through the obstacle.
Once the lane is clear, a BFV platoon from Team B (-) moves forward through
the obstacle. The BFV platoon moves to the front line trace of the infantry
companies and occupies SBF B3. The BFV platoon orients fires on TRP 5 (RFL
1 in effect) with a task to destroy enemy armor in the pass then suppress infantry
on OBJ Dog South (weapons tight). The BFV platoon and A Company can engage
enemy north of RFL 1 with coordination. The intent is to isolate OBJ Dog North
from Dog South with direct fire with the focus of indirect fires remaining
on OBJ Dog North until B Company crosses PL Maple (FCL). No change to the TF
disposition. g.
Figure
5C.
Once
B Company crosses PL Maple (FCL), indirect fires shift off OBJ Dog North with
the focus of indirect fires on OBJ Dog South. A Company and the BFV platoon
(weapons tight) remain focused on TRP 5 (RFL 1 in effect). Once OBJ Dog North
has been cleared, B Company (weapons tight) occupies SBF B4 and orients fires
south on TRP5 (OBJ Dog South). A Company begins movement to PL Maple. The TF
(-) mounted elements transition to REDCON 1. h.
Figure
5D.
A
Company crosses PL Maple which is the trigger for the BFV platoon to lift fires
from OBJ Dog (weapons hold), B Company to lift or shift fires to the west (weapons
tight), and the focus of indirect fires to shift to enemy CATK avenues of approach.
A Company clears OBJ Dog South (with RFL 1 in effect) and then occupies SBF
A2, orienting fires to the west (weapons tight). The BFV platoon moves abreast
of A and B Companies and occupies SBF B4 to overwatch the movement of Team
B (-) through the defile. Team B, the TF advanced guard, initiates movement
through the defile. The 2d serial behind the advanced guard initiates movement
toward PL Birch. The TF is transitioning to the securing phase. Note.
Because of limited CL V and the higher probability of fratricide during the
defile operation, weapons free is not authorized. Subordinate commanders may
issue more restrictive fire control measures based on their situation with
regards to weapons safety posture (see FM 71-1).
3.
Securing
Phase.
a.
The TF should secure an area large enough to accommodate the TF as it exits
the defile. The reconnaissance forces and clearing forces can provide terrain
and enemy information to aid in securing the defile. The TF cannot allow itself
to get "bottlenecked" in the restricted terrain. The TF must be able to defeat
counterattacks during passage. Once through, the TF should rapidly gain control
of the tactical movement (approach march) and continue the attack. The TF may
have to consolidate and reorganize, to include conducting casualty evacuation
(CASEVAC), vehicle recovery, and CL III/V resupply (for example, CLIII for
M1 tanks), prior to continuing the attack. The TF zone of attack may include
additional restricted terrain and another defile drill. b.
Figure
6.
The
BFV platoon moves forward in zone to begin clearing an area large enough to
accommodate the advanced guard.
(1) Reconnaissance forces link up with clearing forces and establish
security on the far side of the defile.
(2) The engineers clear, expand, and mark the route through the
pass.
(3) Team B links up with its southern platoon and initiates movement
through the pass.
(4) A TOW platoon replaces the mechanized platoon in the south and
provides flank security.
(5) The infantrymen on the north side of the pass initiate movement
to link up with the Bradleys.
(6) The mortar platoon is fighting split section with a section
moving behind the advanced guard to set up on the far side of the pass. One
mortar section remains set to provide fire support during movement through
the pass.
(7) The main body has started to move forward by serial/phase line
to facilitate rapid movement through the defile. METT-T determines the priority
for moving through the defile. Consider the use of military police to control
movement (battlefield circulation).
c.
Figure
7.
The
advanced guard (weapons tight) has secured an area large enough to accommodate
the entire TF on the far side of the defile. The TF main body has begun movement
through the defile, one truck-mounted rifle company (serial) at a time. The
infantrymen on the south side of the pass have initiated movement to link up
with their trucks. D Company (or AT platoon) provides flank security during
movement. Note.
Although not graphically depicted throughout the scenario of this article,
CSS assets must be positioned to support the defile operation.
CONCLUSION:
The
intent of this article is to highlight key planning considerations for the
execution of defile operations. Defile drills are combined arms operations.
If not planned, rehearsed, and executed properly, defile operations can result
in significant combat power losses, a loss of momentum, and the TF reaching
its culminating point before it achieves its task and purpose. Execution of
a defile drill is a critical event. It is a means to get to the end (accomplishment
of the TF task and purpose). Also refer to "Truck Infiltration (Assault) Planning
in a Heavy/Light Scenario," CALL's CTC
Quarterly Bulletin, 3d Qtr, FY 99, No. 99-14,
Oct
99.
Techniques
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Applying
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