Infantry Drills

FM 3-21.8 – Appendix E – Helicopter Movement

Appendix E

Helicopter Movement

Infantry platoons may conduct air movement operations to pick up patrols by helicopter, re-supply with helicopters, or evacuate casualties. This appendix discusses general helicopter information including, the five stages of an airmobile operation, how to organize the unit for a helicopter move, and how to select and secure a pickup zone.

 

Section I — Characteristics of Helicopters

E-2.       Helicopters most commonly used by Infantry platoons are the UH-60, Blackhawk and the CH-47, Chinook (Table E-1). See FM 90-4, Air Assault Operations, for information on air movement and air assault operations, and FM 3-21.38, Pathfinder Operations,  for information on pathfinder operations.

Table E-1. Helicopter characteristics.

  UH-60A UH-60L CH-47D
Passenger capacity (seats in) 11 11 33
Passenger capacity (seats out) 18 18 60
Max cargo weight 8,500 lbs. 8,500 lbs. 26,000 lbs.
Cargo hook capacity 8,000 lbs. 9,000 lbs. 26,000 lbs. (center hook)

17,000 lbs (fore & aft hook)

25,000 lbs (fore & aft hook combined)

NOTE: Actual allowable cargo load (ACL) may be determined by ground and aviation unit commanders.

Capabilities

E-3.       Under normal conditions, helicopters can climb and drop at steep angles. This allows them to fly from and into confines and unimproved areas. Other helicopter capabilities include—

– Transporting cargo as an internal load or external (sling) load and delivering to unit areas not supplied by any other means.

– Overflying or bypassing obstacles or enemy in order to reach objectives otherwise inaccessible.

– Flying at low altitudes to achieve surprise and deceive the enemy using hills and trees for cover and concealment.

– Operating under limited visibility conditions.

E-4.       It is ALWAYS preferred to use a helicopter for loading or unloading of troops and equipment.  If terrain prevents the helicopters from landing, troops and their combat equipment can be unloaded while hovering a short distance above the ground with troop ladders, rappelling ropes, or fast ropes. If the aircraft can hover low enough, Soldiers may jump out. The troop ladder (or in limited applications- a SPIES rope) can also be used to extract troops when the helicopter cannot land.

Limitations

E-5.       The large amount of fuel used by helicopters may limit their range and allowable cargo load (ACL). Other helicopter limitations include:

– Extreme weather conditions such as fog, hail, sleet, ice, or winds (40 knots or more) and gusty winds (gusts up to 15 knots above a lull) will prevent the use of helicopters.

– Engine and rotor noise may compromise the secrecy of the mission.

– Limited size or number of suitable landing zones (LZs).

– The load-carrying capability of helicopters decreases with increases of pickup zone (PZ)/landing zone (LZ) altitude, humidity, and temperature.

– Vulnerability to enemy air defense systems and small arms fire.

 

Section II —AirMobile OperationS Stages

E-6.       There are five stages to an air movement operation (Figure E-1). The ground tactical plan is the key planning phase. All other planning is conducted in a backward manner from it. The five stages of this reverse planning sequence are—

(1)   Ground tactical plan (GTP).

(2)   Landing plan.

(3)   Air movement plan.

(4)   Loading plan.

(5)   Staging plan.

 

Figure E-1. Air movement through the five stages.

E-7.       The ground tactical plan drives the entire mission. Convenience of landing considerations is subordinate to putting units on the ground where they can fight. The five plans tie together in this way:

– The ground tactical plan drives the sequence of arrival and amount of combat power onto the LZs.

– Combat power arriving at available LZs to accomplish the mission becomes the landing plan.

– Moving troops and equipment to LZs on the designated flight routes becomes the air movement plan.

– Getting troops and equipment from current friendly locations to the designated LZs dictate the loading plan and PZ locations.

– The PZ loading plan designates the requirements that become the staging plan to move friendly troops onto the PZ when and where needed.

Ground Tactical Plan

E-8.       The ground tactical plan for an air movement operation contains the same essential elements as other Infantry missions, but differs in one area: it is prepared to capitalize on the speed and mobility of the aircraft to achieve surprise. Units are placed on or near the objective to immediately seize the objective. The ground tactical commander, in accordance with doctrine and METT-TC, determines his ground tactical plan. The five stages of the reverse planning sequence cannot be developed independently.  In addition to standard planning considerations for actions on the objective, the commander’s plan should include—

– H-hour times.

– Primary and alternate LZ(s).

– Means of identifying LZ(s).

– Task organization.

– Chalk configurations.

– Special equipment required (such as kick-off bundles, ropes).

– Attack aviation assets available and missions.

– Suppression of enemy air defenses (SEAD).

– Landing formations.

– Offloading procedures.

Landing Plan

E-9.       Unlike approaching an objective in armored vehicles, Soldiers in helicopters are most vulnerable when landing, and are potentially more vulnerable to enemy fire than if they were on the ground. Suppressive fires are employed to deny the enemy unhindered access to the landing forces, so the timing of fires is critical to the success of the landing.

E-10.     The ground tactical commander’s plan typically results in two types of landing plans: on the objective (within enemy small arms range), or away from the objective (outside of enemy small arms range). Landing away from the objective is the more common of the two landing plans. The mobility and speed of the helicopters further enables the unit to land to the rear of the objective and aid in the element of surprise and confusion during any subsequent assault. Table E-2 lists factors considered when constructing the landing plan. Regardless of the landing plan used, the Infantry platoon must land ready to fight.

Table E-2. Landing plan considerations.

Factors

Land away from the objective (outside of enemy small arms range) when…

Land on the objective (within enemy small arms range) when…

Mission The mission is enemy force-oriented. The mission is terrain-oriented.
Enemy There is incomplete intelligence on enemy disposition. There is precise intelligence on enemy dispositions.
Terrain There is incomplete intelligence on terrain (especially LZs) and weather, or there are no suitable LZs on or near the objective. There is precise intelligence on terrain (especially LZs) and weather, and there are suitable LZs on the objective.
Troops available Conditions are not set. Conditions are set and verified.
Time There is time available to develop the situation. Time is critical to secure the objective.
Intent The unit plan is to arrive at the LZ prepared to move out quickly and ensure rapid advance on objective. The unit has a plan to establish continuous suppression of any enemy fire immediately upon landing while aggressively assaulting to secure the objective.

E-11.    Good PZs and LZs allow for helicopter insertion or extraction without exposing the unit or aircraft to unnecessary risks. Three-hundred-and-sixty-degree security must be maintained at all times. Preparatory and supporting fires are planned to suppress the enemy as the aircraft land on the LZ or the PZ. The control and distribution of all available means to suppress the enemy at a most vulnerable time is imperative. Fires should be focused along the base of the exit tree line (right door exit shoots at the right tree line). Regardless of threat data, suppressive fires are planned, although not necessarily executed, for every primary and alternate PZ or LZ. Whether a PZ or LZ, units establish a defensive posture and employ local security measures as required, shifting as necessary when chalks land or depart.

E-12.    The ground tactical commander, in coordination with the supporting aviation unit, selects the location of helicopter PZs and LZs. There are many factors that leaders must consider when choosing appropriate LZs and PZs. These requirements are covered by aviation unit SOPs or are prearranged by the aviation unit commander in coordination with the pathfinder leader. The final decision concerning minimum landing zone requirements rests with the aviation unit commander. Among those factors considered is the number, type and landing formation of the helicopters, surface conditions, obstacles, ground slope, approach and departure route, atmospheric conditions, and type of loads.

Number, type, and landing formation of the Helicopters

E-13.    The number, type, and landing formation of helicopters determine the minimum landing space requirement and total size of the LZ and PZ.  It may be necessary to have two PZs or LZs, or to land the necessary aircraft one at a time. Differing aircraft may have different landing point size requirements.  A single UH-60 requires a touch down point (cleared area) of 50 meters in diameter without sling load, and 80 meters with sling load.  A CH-47 requires a touchdown point of 80 meters in diameter without sling load, and 100 meters with sling load.

Surface Conditions

E-14.    The surface at the landing point must be firm enough to keep helicopters from bogging down, raising too much dust, debris, or blowing snow. Troops remove loose debris that may damage the rotor blades or engines.

Obstacles

E-15.    Helicopters should not land on a landing point that includes obstacles. An obstacle in this case is defined as any object or terrain feature (anything 18 inches high or deep) that could cause damage to the airframe or rotor system of the aircraft, or prevent safe landing. Objects or equipment placed on the PZ/LZ in conjunction with the operation (such as landing lights and slingloads) are not included.  Obstructions (for example, rocks, stumps, and holes) that cannot be removed must be clearly marked. Methods of marking obstacles that cannot be cleared for both day and night must also be considered.

Ground Slope

E-16.    When the slope is less than 7 percent (4 degrees), helicopters may land in any direction.  Where ground slope is from 7 to 15 percent (4 to 8 degrees), aircraft must land and park sideslope or upslope.  Helicopters with skids as landing gear may not land, but must terminate at a hover.  If ground slope is greater than 15 percent (8 degrees), helicopters cannot land safely, and may sometimes hover to drop off Soldiers or supplies.

Approach and Departure Routes

E-17.    The direction of departure and landing should be generally into the wind, over the lowest obstacle, and along the long axis of the LZ.  If there is only one satisfactory approach direction because of obstacles or the tactical situation, most helicopters can land with a slight crosswind or tailwind.  PZs or LZs should be free of tall trees, telephone and power lines, and similar obstructions on the approach and departure ends.  Use an obstacle ratio of 10:1 when determining how much additional space is required for landing and take-off. A helicopter needs 100 meters of horizontal clearance from a 10-meter tree for takeoff or landing.

Atmospheric Conditions

E-18.    As the humidity, altitude and temperature increase, the performance capability of aircraft decrease.  This result in greater fuel consumption, lower ACLs, and larger LZ requirements. These limitations/considerations should be highlighted by aviation LNOs during planning.

Type of Load

E-19.    Most helicopters cannot take off or land vertically when fully loaded, so a larger LZ/PZ and better approach and departure routes may be required for fully loaded aircraft.  LZs must be larger for aircraft delivering sling loads compared to aircraft delivering internal loads and Soldiers.

Other Considerations

E-20.    Other considerations when selecting PZs and LZs include:

– Location in relation to objective.

– Ability of the unit to secure.

– Enemy location, capabilities, and strength.

– Cover and concealment.

– Identification from air.

– Weather and its effect.

– Visibility (darkness, fog, snow, dust, etc)

Air Movement Plan

E-21.    Air movement involves flight operations from PZ, to LZ, and back. The Infantry leader and all chalk leaders should maintain the following items:

– A marked air route map.

– Compass/GPS.

– Watch synchronized with the flight crew and ground element.

– Air movement table, PZ sketch, and LZ sketch.

– Call signs and frequencies for all aviation and ground units involved in or around the operation.

– Backpack FM radio.

E-22.    The air movement plan includes en-route security for the lift aircraft by attack aviation. It also includes, false insertions to deceive the enemy, suppression of enemy air defense positions along the flight route, and emergency procedures in the event an aircraft is lost en route due to maintenance or enemy fire.

E-23.     To maximize operational control, aviation assets are designated as lifts, serials, and loads.  A lift is all utility and cargo aircraft assigned to a mission. Each time all assigned aircraft pick up troops and/or equipment and set them down on the LZ, one lift is completed. The second lift is completed when all aircraft place their second load on the LZ.  There may be times when a lift is too large to fly in one formation. In such cases, the lift is organized into a number of serials. A serial is a tactical group of two or more aircraft and separated from other tactical groupings within the lift by time or space. The use of serials may be necessary to maintain effective control of aviation assets when the capacity of available PZs or LZs is limited or to take advantage of available flight routes.  The personnel and equipment designated to be moved a single aircraft is called a load or chalk. Each chalk must have a chalk leader who ensures that every man in his chalk gets on and off the helicopter, that everything is ready to load, and that everything gets loaded and unloaded correctly. The chalk leader should sit in the aircraft where he can best stay oriented during flight and where he can get off quickly at landing sites to control his men. Figure E-2 shows the relationship between a chalk, serial, and lift.

Figure E-2. Lifts, serials, and chalks.

Loading Plan

E-24.    Air movement operations do not succeed on the PZ, but the failure of the mission can occur there. Therefore, PZs must be established to run efficiently. Assault forces are organized on the PZ, not the LZ. Every serial must be a self-contained force that understands what it must do on landing at either the primary or alternate LZ, and later in executing the ground tactical plan.

E-25.    Before an Infantry platoon is lifted by helicopter, it must be organized for the move. The load (amount of men, weapons, equipment, and ammunition) that can be carried by a helicopter varies. It is based on the type of helicopter used, configuration of the helicopter, temperature, altitude of the PZ or LZ, humidity, and fuel load. What can be carried is the allowable cargo load (ACL).  This is one of the main factors considered when planning aircraft loads. When the Infantry platoon is alerted for a movement by helicopter, the allowable cargo load will be given to the leader. The unit can then be organized into chalks/loads based on the given allowable cargo load of each type of aircraft.  Page E-5 displays an example of a “Tadpole Diagram” (Figure E-3) that is used to plan and organize the chalks and loads.

Figure E-3. Tadpole diagram.

E-26.    The leader maintains the tactical integrity and self-sufficiency of each aircraft load as much as possible. He maintains tactical integrity by keeping squads and fire teams intact on chalks and the platoon intact within a serial. He maintains self-sufficiency by loading a machine gun and its ammunition and crew, or an entire antiarmor team on the same aircraft. Key men, weapons, and equipment should be cross-loaded among different aircraft. Platoon leaders and platoon sergeants should fly on separate helicopters. So should machine gun teams. This kind of cross-loading can prevent the loss of control or unit effectiveness in the event a helicopter is lost.

E-27.    The leader prepares a load plan for the platoon that tells each man which aircraft he is to get in and who the chalk leader is.

E-28.    The chalk leader tells each man in his chalk where to sit, what to do in case of emergency, and what to do when the aircraft lands.

Staging Plan

E-29.    As part of the staging plan, Soldiers must mark obstacles on the PZ in both day and night operations. In daylight, troops use red panels or other easily seen objects and materials to mark obstacles. In night operations, units use signal lights to avoid security problems. Visible or infrared lights can be used, but the choice must be coordinated with the lift unit. In any case, pilots should be advised of obstacles whether marked or unmarked.

E-30.    For a night operation, Soldiers can use flashlights, chemical lights, or expedient devices to show the direction of landing and to mark aircraft landing points. However, pilots cannot see blue or green chemical lights under aviator night vision goggles. Therefore, blue and green chemical lights should be used for Infantry staging purposes only. Always use red, orange, yellow, or infrared for aircraft positions.

E-31.    There are many ways to mark a PZ or LZ at night. The inverted “Y” is one way. An inverted “Y” indicates the landing point of the lead aircraft and its direction of approach. The formation used by the aircraft will determine how to place the lights for other aircraft. Table E-3 lists examples of PZ markings during day and night operations.

E-32.    Security on the PZ is of the utmost importance.  It may be conducted by a separate unit that is not conducting the air movement.  At a minimum, the Infantry platoon secures itself and maintains a high state of readiness while awaiting arrival of the aircraft.

E-33.    Whenever possible, Infantry platoons should conduct “cold-load” rehearsals prior to conducting an air movement.  This can be done on the actual aircraft (best method), or using field expedient methods.  Chalk leaders arrange their chalk considering the last one to load the aircraft is the first one off.  Soldiers are designated to open/close doors, secure and unload equipment, and understand the direction they will move or secure once getting off the aircraft.  If the lift aircraft arrives at the LZ before execution of the mission, the chalk leader should conduct face-to-face coordination with the air crew.  This is done to ensure everyone knows the PZ on-load and LZ off-load procedures.  It also avoids confusion and speeds actions on the LZ, allowing the aircraft to spend minimal time on the ground.  Information that should be coordinated include:  which door(s) will be used to load and unload; actions if the aircraft takes enemy fire en route and on the ground; special safety considerations; crash procedures; location of the primary and alternate LZs; direction of landing; time warnings with hand and arm signals inside the aircraft; and any other special mission requirements.

Table E-3. Example PZ marking methods.

Position

Day

Night

PZ entry point for Infantry NCOIC, signage NCOIC, two blue chem lights
PZ control point HMMWV and VS-17 panel Green chem lights on antennae
Chalk stage points Guides, signage Guide, blue chem light
Lead touchdown points VS-17 panel Inverted “Y,” infrared lights
Aircraft touchdown points VS-17 panel Red chem light per aircraft
Obstacles FM communication Red chem light ring around obstacle
Loads to be picked up Hook-up teams stationed on loads Swinging infrared chem light per load

Section III —  Safety

E-34.    Infantry leaders must enforce strict safety measures when working with helicopters. Measures include:

– Avoid the tail rotor.  Never approach or depart to the rear of a helicopter except when entering or exiting a CH-47. Approach from 3 or 9 o’clock is preferred when using UH-60s.

– Keep a low body silhouette when approaching and departing a helicopter, especially on slopes.

– Keep safety belts fastened when helicopter is airborne.

– Keep muzzle pointing down and on safe.

– Keep all radio antennas down and secure.

– Keep hand grenades secured.

– Do not jump from a hovering helicopter until told to by an air crew member.


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