The external air transport method of carrying cargo and equipment by helicopter overcomes many of the obstacles that hinder other modes of transportation. Helicopters move cargo as external slingloads when--
Pathfinder qualified personnel are prepared to organize and control external load pickup or drop-off sites as an integral part of LZ operations. A detailed load plan to include approximate weights and sequences of load movement, is provided by the supported unit to ensure the correct and expeditious movement and placement of cargo.
- The cargo compartment is too small for the load.
- The helicopter's center-of-gravity limitation is exceeded by the characteristics of an internal load.
- Maximum speed is required to load and unload.
- Conditions on the LZ prevent touchdown of the aircraft.
All slingloading operations
use size 4 or 5 landing points (80- to 100-meter diameter) regardless
of type or size of helicopter. Conditions of the area, such as
a dusty surface or obstacles, often require increasing the minimum
spacing between loads, reducing the number of helicopters that
can safely operate at the site at the same time, and decreasing
the overall speed of the operation.
All external loads are divided
into three categories: high density, low density, and aerodynamic.
Each load exhibits different characteristics in flight. The high
density load offers the best stability; the low density load the
least. The aerodynamic load is unstable until load-streamlining
occurs; then it becomes stable. Pathfinders determine the category,
size, and weight of the load during the planning phase of the
There are three elements involved in most slingload operations: The supported unit (the unit whose equipment will be moved), the supporting unit (the aviation unit that will fly the loads), and the pathfinder element.
Rigging the loads is the responsibility
of the supported unit. However, pathfinders should check weight,
rigging, and positioning of all external loads to ensure helicopter
safety. Ideally, the supported unit provides hookup men for individual
loads. Their specific responsibilities are:
a. Supported Unit.
(1) Coordinating in advance
with the supporting unit.
(2) Actual rigging of the
(3) Furnishing slings, straps,
clevises, and any other slingload equipment required for the move.
(4) Ensuring that the loads
are properly rigged and do not exceed the allowable cargo load
of the aircraft.
(1) Providing advice and technical
assistance to the supported unit as required.
(2) Ensuring that the loads
do not exceed the ACL of the transporting aircraft.
(1) Providing advice and assistance
to the supporting unit and the supported unit.
(2) Providing expertise in
the planning and execution of both PZ and HLZ operations.
(3) Supervising the rigging
and inspection of all the loads.
(4) Providing ground guidance
and air traffic control during the slingload.
(5) Ensuring that the loads
do not exceed the ACL of the aircraft.
Cargo nets and slings are
an essential part of the external load operation and must be given
the same attention during inspection that the cargo receives.
Any evidence of frayed or cut webbing justifies replacing the
component. Because of the critical strength requirements, field
sewing of nylon and substitution of nonstandard parts should not
be done when assembling slings. The sling assembly must meet load
requirements (paragraph 5-6 and FM
a. Sling Assembly.
The Army's inventory has a variety of equipment that is either
adapted for use or designated for use in slingload operations.
(1) Aerial delivery slings.
These slings were originally designed for airborne delivery
of heavy loads, but they have been adopted for use in air assault
operations. There are a variety of ADS sizes and strengths:
Two-loop slings: 5,500 pounds
with 4 thicknesses.
Three-loop slings: 8,300 pounds
with 6 thicknesses.
Four-loop slings: 11,100 pounds
with 8 thicknesses.
Two-loop slings: 3,500 pounds
with 4 thicknesses.
Three-loop slings: 5,250 pounds
with 6 thicknesses.
Four-loop slings: 7,000 pounds
with 8 thicknesses.
Two-loop slings: 8,900 pounds
with 4 thicknesses.
Three-loop slings: 13,500
pounds with 6 thicknesses.
Four-loop slings: 17,000 pounds
with 8 thicknesses.
Six-loop slings: 27,000 pounds
with 12 thicknesses.
Two-loop slings: 5,600 pounds
with 4 thicknesses.
Three-loop slings: 8,500 pounds
with 6 thicknesses.
Four-loop slings: 11,200 pounds
with 8 thicknesses.
Six-loop slings: 17,000 pounds
with 12 thicknesses.
(a) Type X nylon slings are
issued in 3-, 8-, 9-, 11-, 12-, 16-, and 20-foot lengths for slingload
(b) Rated tensile strengths
for Type X nylon ADS used as a pendant are:
(e) Rated tensile strengths
for Type XXVI nylon ADS used as a pendant are:
(h) Four-loop Type XXVI nylon
slings are issued in 3-, 9-, 11-, 12-, 16-, 20-, and 28-foot lengths.
(i) Six-loop/Multiloop Type
XXVI nylon slings are issued in the following lengths: 60-foot
and 120-foot lengths.
(j) Three-foot ring tensile
strength is 10,000 pounds for either the three-loop Type X nylon
or two-loop Type XXVI nylon. Dual rings have a tensile strength
of 17,500 pounds.
(a) Choker hitch. Pull the
free running end of the sling around the point of attachment and
draw it between the loops of the sling's standing end After ensuring
that the cotton buffer is properly in place, milk the keeper of
the standing end down to secure the sling.
(b) Basket hitch. Separate
the loops of the sling at one end and place the sling over the
suspension point. Ensure that the cotton buffer is emplaced properly,
then milk the keeper down towards the suspension point to secure
b. Nets and Containers.
There are two sizes of cargo nets (5,000-pound capacity and
10,000-pound capacity) and a variety of cargo containers in the
Army system. The 5,000-pound capacity net (NSN 1670-01-058-3811,
LIN N02776), the 10,000-pound capacity net (NSN 1670-01-058-3810,
LIN N02781), and the A-22 cargo bag are the most common external
load facilitators in the Army.
(1) The 10,000-pound capacity
cargo net, which is 18 feet by 18 feet, is used for external transport
of boxed or bulky loads. The net has a maximum capacity of 10,000
pounds and will not be flown with a load that is less than the
prescribed weight determined by the aviation unit. Do not drag
the net across the ground. Use a canvas insert when carrying items
small enough to slip through the netting.
(2) The A-22 cargo bag is used to externally transport standard palletized loads, loose cargo, ammunition, oil drums, and other general items. Its maximum capacity is 2,200 pounds. The minimum capacity for external operations is determined by the aviation unit. The A-22 may be used with or without the canvas cover.
5-5. SERVICE LIFE OF AERIAL
The date that the sling was
put into service will be stamped on the sling in one-inch letters
near the first keeper at both ends using an orange-yellow or strata
blue parachute tube-type marker only. This date will be used to
determine the date of the next inspection. Slings will be inspected
every six months by the user, and the date of the inspection will
be stenciled on the sling using different color ink or tube marker.
First, line out the old date. If the old date is in strata blue,
cover the date with strata blue and remark it in orange-yellow.
Only one date should appear on the sling. Slings will also be
inspected both before and after each use. If the condition of
the sling is questionable the sling will be removed from service
a. General Inspection.
When inspecting nylon air items, look for any indications of the
(1) Overdue inspection date.
(2) Evidence of foreign matter:
mildew, paint, grease, oil, or any other deteriorating chemical.
(6) Broken stitches (more
than two consecutive broken or loose stitches, or five or more
broken stitches overall in the sewn portion will render the item
(7) Cotton buffers, sliding
keepers, or permanent keepers missing.
b. Cargo Strap. The
A7A is a cotton or nylon cargo strap that is 188 inches long,
and each has a rated capacity of 500 pounds. Located on one end
of the strap is a friction adapter with a thick-lipped metal floating
bar. The strap is issued with one metal D-ring. Inspect this piece
of equipment for cuts or frays.
c. Cargo Tie-Down Equipment.
Check the tie-downs for serviceability.
(1) The CGU-lB cargo tie-down
device has a rated capacity of 5,000 pounds. Its length is adjustable.
(2) The 15-foot cargo tie-down
strap with a quick-fit strap fastener has a rated capacity of
(3) The 5,000-pound and 10,000-pound
load binders have their rated capacity stamped on their sides.
(1) The Type IV link assembly
is used to construct the 3-foot donut or to connect one ADS to
another. It has a rated capacity of 12,500 pounds, and its NSN
is 1670-00-783-5988. When inspecting the Type IV link assembly,
look for the following deficiencies:
Aluminum buffers not rotating
Posts that are bent or cracked.
Bent slide connectors.
No metallic "click"
(a) Large suspension clevis
(NSN 1670-00-090-5354). It has a rated capacity of 12,500 pounds
(pendant); 7,875 pounds sling to lifting provision point of attachment.
It is used with CH-54 aircraft.
(b) Medium suspension clevis
(NSN 1670-00-678-8562). It has a rated capacity of 6,250 pounds
(pendant); 3,750 pounds sling to lifting provision.
(c) Small suspension clevis
(NSN 1670-00-360-0304). It has a rated capacity of 6,250 pounds
(pendant); 3,750 pounds sling to lifting provision.
e. 15,000-Pound Capacity,
Multi-Leg Sling Set. The nylon and chain multi-leg sling set
has an overall length of 23 feet and a rated capacity of 15,000
pounds. It weighs 94 pounds complete. It includes a 12-inch nylon
web ring, consisting of seven thicknesses of nylon webbing secured
with a connector link, four 15-foot nylon slings, a 10-inch grab
link assembly with coupling link (each leg), and a 6-foot chain
(each leg) with 64 links (Figure 5-3). Each component of the multi-leg
chain set has a rated capacity of 5,560 pounds when used as a
pendant. When inspecting the multi-leg chain set, inspect all
metal and nylon items as per paragraph 5-6d; inspect the connector
link; inspect the gate of the grab link assembly and ensure it
is under spring tension. Inspect the chain for 64 links. (Reference FM
f. Large Capacity Sling
Sets. The new 10,000-pound (Figure 5-4) and 25,000-pound capacity
sling sets appear similar. However, all components of the sets
are marked so take care not to mix components of the two sets.
See Table 5-1 for identifying characteristics.
Each set has four legs. Each of the legs has a rated capacity
of l/4th the total capacity of the set. It is common to use up
to six legs on some loads. The extra two legs DO NOT increase
the rated capacity of the entire set. When taping the apex fitting
pin, it is only necessary to tape the side with the retaining
bolt and nut. Unlike the clevis, the bolt and nut are tightened
with a wrench.
(1) The nylon rope assembly
for each set has an interwoven eye at each end. This eye is covered
with polyurethane potting to protect the leg from abrasion and
ultraviolet radiation (Figure 5-4). Each rope is double braided
and is connected to a grab hook assembly (Figures 5-5, 5-6, and 5-7). The grab hooks for the two sets look alike, but they are
not interchangeable because they have different ratings.
(2) Refer to Chapter 6, FM
55-450-3 to learn how to inspect the new rope sling sets and to
Appendix D, FM
55-450-3 for sling conversion tables.
5-6. AIRCRAFT LOAD LIMITATIONS
The maximum weight that any
aircraft can carry via an external slingload is determined by
the structural strength of the cargo hook assembly. In most cases,
it is not the tensile strength of the hook that will limit the
weight that an aircraft can lift-it is the allowable cargo load
that is the limiting factor. The ACLwill most always be less than
the capacity of the cargo hook assembly (Figures 5-1 through 5-5).
a. Cargo hook tensile strengths
for US Army aircraft (Figures 5-8 through 5-11) are:
b. The ACL is based on the
type of aircraft, age of the airframe, altitude above sea level,
temperature, humidity, and the aviation unit's SOP.
When using a UH60 Black Hawk
for air lift, coordinate closely with the aviation unit for the
(1) M998/M1038 truck, cargo,
1 1/4-ton (HMMWV)
5,200 pounds empty
7,700 pounds loaded
6,050 pounds empty
8,200 pounds loaded
(add 500 pounds if equipped
with a winch)
Empty: 2,540 pounds
Full: 6,060 pounds
Empty 2,540 pounds
Full: 6,060 pounds
Empty: 2,800 pounds
Full: 6,320 pounds
(1) M101 105-mm Howitzer
(add 300 pounds if equipped
(add 170 pounds for section
|Fuel||55-Gallon Drum||500-Gallon Blivet|
|(1) Gasoline(MOGAS)||404 pounds||3,400 pounds|
|(2) Gasoline(JP4/JP8)||410 pounds||3,500 pounds|
|(3) Diesel fuel||457 pounds||3,800 pounds|
|(4) Lube oil(30 weight)||479 pounds||4,000 pounds|
Several types of expendable
rigging supplies are necessary to complete the rigging of the
following loads. These supplies include l/4-inch cotton webbing,
l/2-inch diameter rope, Type III nylon cord (550 pound test),
pressure sensitive tape, cellulose wadding or paperboard honeycomb,
and canvas/felt padding. Sufficient supplies of these items should
be on hand prior to rigging the loads.
a. For detailed preparation
and rigging of the following loads, refer to FM
b. Loads rigged with ADS and
having more than one suspension point require that the ADS be
twisted once for each 3 feet of sling length. This is to minimize
vibration in the sling during flight. The nylon and chain multi-leg
sling sets and the 10,000 and 25,000 pound capacity sling sets
do not require the twists.
(1) 10,000-pound capacity
nylon cargo net (18 feet by 18 feet):
One A7A cargo strap.
Two 16-foot, 2- or 3-loop
One 3-foot ADS with one Type
IV link assembly (for doughnut).
One or two drums Sling set,
Refer to FM
55-450-3 for rigging
One A-22 kit.
One A7A cargo strap.
One 8-foot, 2- or 3-loop ADS.
One 3-foot, 2- or 3-loop ADS
with one TYPE IV link assembly (for doughnut).
(5) A-22 cargo bag:
The behavior of an external
load while in flight can greatly affect the performance of the
aircraft carrying it; therefore, it is important to minimize the
load's drag on the aircraft. High drag coefficients will reduce
the airspeed of the aircraft, will take longer to complete the
task or cause it to be incomplete because allotted time has expired,
and could possibly endanger the aircraft and its crew. (A helicopter
pilot will not hesitate to "punch a load" if he feels
that his aircraft is endangered.) To minimize drag, it is necessary
to stabilize the load. The following methods can be used to accomplish
a. Reduce the Airspeed
of the Aircraft. Having the aircraft fly slowly enough that
the load does not become unstable is the least desirable method
to use. This bums extra fuel and takes more time to do less work.
Loads should be configured so that they will fly at speeds of
60 knots or more.
b. Add Weight to the Load.
Heavier loads are less affected by the air pushing-against
them while they fly, hence they tend to be more stable. However,
make sure you do not exceed the rated capacity of your equipment
or the ACL of the aircraft.
c. Streamline the Load.
Long symmetric loads will fly crosswise to the direction of
flight causing immense dragon the aircraft. Loads tend to stabilize
if the center of gravity is located in the first one-third of
the load. By adjusting the load and, if needed, adding weight,
it is possible to move the CG toward one or the other end. The
lighter tail end of the load will act much as the fins on a dart
The heavier end of the load will "seek" the direction
of flight and the load will stabilize.
longer the slings that attach the load to the aircraft, the less
stable the load will be in flight. Additionally, the closer the
angle of the slings to horizontal the greater the stress
put upon them. For example, a total vertical stress of only 3,000
pounds will put a stress of 4,242 pounds on a sling at an angle
of 45 degrees. Be aware that as the angle decreases to 5 degrees,
the stress on the sling reaches 34,419 pounds.
The chart in Figure 5-12,
illustrates the variations of tension on one sling leg when applied
to a constant 1000-pound load at various angles.
PROBLEM: A four-leg sling assembly with each leg lifting at an angle of 45 degrees will be used to lift 10,000 pounds of weight. What will be the tension on one leg?
PROCEDURE: From the chart the total
sling tension on one leg at 45 degrees for 1,000 pounds is 1,414
5-10. HOOKUP AND RELEASE
Hooking up a load requires
a team effort. The signalman must position the aircraft over the
load so that the slingload team can discharge the static electricity
and attach the load to the aircraft as quickly and safely as possible.
Release of the load is done by the air crew in most cases and
does not usually require any ground crew except the signalman.
a. Ground Crew Protective
Measures and Equipment. Ground crews working around hovering
helicopters are exposed to a variety of hazards. The danger to
the crews cannot be overemphasized, and measures to ensure their
safety should be of the utmost importance. To protect the crews,
the following equipment (Figure 5-13) is recommended or required.
(1) Helmet. It affords
protection against head injuries from flying debris, from being
caught between the aircraft and the load, and so forth. Helmets
will be securely fastened.
(2) Protective mask or
dust goggles with respirator. These assist the crew by protecting
the face, eyes, and respiratory system against airborne particles
stirred up by the rotor wash. The mask protects better, but it
can cause problems with depth perception (important for signalmen).
Masks or goggles are required in high dust/debris environments.
(3) Ear plugs or a suitable
substitute. These protect against the excessive noise associated
with hovering aircraft and prevent debris from entering the ear
(4) Hand protection. Marine
Corps and Navy personnel are required to wear electrical workers
gloves for static discharge burn protection. All other personnel
(USA USAF, and USCG) should wear leather gloves to help protect
their hands and fingers. If electrical workers gloves are available,
all static wand persons should wear them for added protection
from static discharge burns.
(a) To ensure adequate protection,
these shockproof gloves must be inspected before and after each
operation. They should be checked for excessive wear, fraying,
holes, and tears. Do not use a torn glove.
(b) Even a small hole leaves
a person unprotected from static electric shock. Gloves can be
checked for holes by filling them with water and squeezing them
while holding the open end closed, or by blowing air into them
like a balloon and submerging them in water. Any holes will cause
(a) To avoid the possibility
of a static electric shock, ground crewmen use static discharge
wands (field expedient and manufactured) and grounding stakes
to ground the cargo hook. Since these wands connect the helicopter
to the ground, the static electric charge is dissipated and the
hookup man will not receive a shock when he connects the apex
fitting to the cargo hook.
(b) Inspect the static discharge
wand to make sure it is in serviceable condition. Select the grounding
stake location; it should be on the opposite side of the ground
crew's exit direction so they will not trip over the cable as
(c) Drive the stake into the
ground until it is firmly seated--at least 6 to 8 inches infirm
ground and 24 inches in sandy or loose soil. Drive the stake in
at a 45-degree angle away from the side of the load in case someone
falls on it. Connect the cable clamp to the vertical shaft of
(d) When operating on concrete
or asphalt surfaces, position loads as close to the edge of the
surface as possible so that the grounding stake can be driven
into the ground.
(e) Do not hold the static
discharge wand within 14 to 16 inches of the metal hook end--a
strong static charge can jump up to 12 inches. To be effective,
the static discharge wand must maintain contact with the cargo
hook during the hookup operation. If contact is lost, all personnel
will pull back from the hook until contact is reestablished between
the wand and the aircraft's cargo hook.
(1) Wear long-sleeved shirts
with the sleeves rolled down and fastened. Button the shirt collar.
Tuck shirt tails or jacket bottoms into the trousers.
(2) Police the operational
area thoroughly before conducting sling-load operations to reduce
the amount of debris that can be thrown about by the rotor wash.
(3) Remain alert during hookup
and release operations; sound judgment and common sense are the
keys to success. Be ready at all times to get clear of the load;
soldiers have been crushed between the aircraft and loads, have
had loads dragged over them, or have taken an unwanted ride because
they inadvertently became entangled with the load. Exercise particular
care during hookup operations if the crew must mount the load
to affect hookup. Slings under tension can easily crush an arm
or leg against the load. Some of the particular hazards associated
with loads are:
(a) Cargo extensions/projections.
Gun tubes, landing gear, missile launchers, bridge planks, and
so forth can interfere with or injure the ground crew by striking
or tripping them. Crewmen should stand clear of such projections
or position themselves so that they can immediately clear the
(b) Sharp projections, hooks,
and protruding handles or levers, such as tarpaulin tie-down hooks,
door handles, sparetire racks, and similar projections, should
be avoided by the ground crew if possible. Serious injury can
be caused by the sharp edges, and a crewman could easily become
hooked to the load should his clothing or part of his equipment
catch on one of these items. The crew should be alert and be prepared
to move immediately to avoid injury.
(c) Top heavy or narrow-based
loads that can fall over from the rotor wash should be treated
with caution. If possible, position these loads on their side
before hookup. If this is not feasible, position the crew on the
side or end of the load that is least likely to tip. The crew
should be prepared to clear the load immediately.
(d) High loads can cause serious
injuries to crewmen who are required to climb to the top of the
load to affect hookup. They may be swept off the load by the rotor
wash, or they may find it necessary to jump to avoid a dangerous
situation. Crewmen on top of a load must pay attention to where
they stand. If at all possible, they should not stand on the top--rather
on a lower projection or step so that should the aircraft make
contact with the load they are not caught in between. The crew
should work from a crouched position or from their hands and knees.
If possible, have a vehicle backed up to the load that can be
used as a working platform. (Move the vehicle before lifting the
load.) The crew should use solid footholds and handholds and be
ready to clear the load immediately.
(1) The signalman will be
facing the aircraft. He should move to a point where he will be
(2) The hookup men may be
under the aircraft at the time of the emergency. They should try
to work along the RIGHT side of the load so that they do not have
to climb over or go around the load to seek safety. They would
then be able to move directly off and away from the load. If the
load is a heavy piece of equipment, they may wish to keep the
load between them and the aircraft while they are moving. This
will offer them some protection should the aircraft crash.
- (1) Duties of the signalman.
(a) Before the arrival of
the aircraft, the signalman directs the positioning of the load.
He supervises the inspection of the load for proper routing of
the slings and proper preparation. He also ensures that the load
is ready to fly.
(b) As the helicopter approaches,
the signalman stations himself 20 meters in front of the load
to maintain eye contact with the crew and gives the arm-and-hand
signal of "assume guidance." As the helicopter reaches
the vicinity of the load, he uses arm-and-hand signals to position
the cargo hook of the aircraft directly over the load and close
enough to the load so the hookup men will be able to place the
apex fitting onto the cargo hook During this time, it is critical
that the signalman positions himself so that the pilot can see
his signals easily. Since the pilot of an Army aircraft is located
on the aircraft's right side, the signalman will usually be located
slightly to the aircraft's right. If terrain in the area forces
him to place himself elsewhere, he must ensure that he is in the
pilot's view at all times, regardless of where he is positioned.
(c) During the hookup process,
the signalman must also observe the cargo hook and apex fitting.
Once hookup has been accomplished, he must hold the aircraft at
a hover until the hookup men are clear of the load. When they
are clear, the signalman signals the aircraft upward slowly so
that the sling legs gradually take up the load. This is done to
check that the sling legs are not fouled on the load. If they
are fouled, the signalman motions the pilot downward and then
instructs him to cutaway the load. If the load has been successfully
suspended, the signalman will give the aircraft the signal to
depart then move quickly aside to clear the helicopter's path.
(2) Duties of the hookup
(a) One man handles the static
discharge wand and the cargo hook; the other controls the apex
fitting of the slingload. Hookup must be done rapidly to reduce
helicopter hover time and minimize the exposure time of the hookup
men under the helicopter.
(b) The hookup men will be
in position at the load when the helicopter arrives. As the helicopter
hovers over the load, the hookup men position themselves so that
the hookup can be quickly accomplished. They make sure the signalman
can continually observe the operation.
(c) When the helicopter is
in the correct position for hookup, the static wand man grounds
the aircraft by contacting the static wand to the cargo hook (Figure
5-14) and maintains continuous grounding contact The other hookup
man then places the apex fitting onto the cargo hook and ensures
that the hook is properly closed (and locked, if required).
(d) After the load is properly
hooked to the aircraft, the hookup team moves quickly aside to
the designated location coordinated with the aviation unit. If
any of the legs become fouled and it is necessary to rehook the
load, the crew signalman notifies the pilot.
the cargo hook cannot be opened either by activating it from within
the helicopter or by the action of the cargo release men, emergency
cargo release procedures must be accomplished. Try to disassemble
the doughnut and pass the ads through the hook. If a clevis or
apex fitting is used as the attachment point to the cargo hook,
unscrew the nut and remove the pin. In some cases, it maybe necessary
to quickly derig the load so the aircraft can set down and resolve
f. Hookup Procedures During White-Outs or Brownouts. Due to the nature of these conditions (snow or dust), a signalman is not required and a hover hookup is not safe.
- (1) Rig the load with a 20-foot or a 40-foot extension as required using 20-foot, 2- or 3-loop ADS, and the appropriate number of Type IV link assemblies. Place an apex fitting at the end of the extension.
(2) Lay the extension to the left of the load, and the aircraft will approach noramally then taxi to the loacation of the apex fitting and set down. Once the aircraft is on the ground, the hookup man moves to the aircraft and attaches the apex fitting to the cargo hook (Figure 5-15). The aircraft suspends the load normally and departs as sirected by the GTA.
When attaching the extension to skid-equipped helicopters (UH-1H for example), exercise care so that the sling does not pass through the skid. Route the sling forward of the skid and then attach it to the cargo hook.
Coordinate the evacuation route of the ground crew to a rendezvous
point with the liaison officer or helicopter crew before the start
of the operation. Proper coordination will prevent any mix-up.
Helicopter emergency procedures depend on terrain, wind direction,
and pilot choice. Good prior coordination will prevent the helicopter
and the ground crew from moving in the same direction.
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