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CHAPTER 4

M901-SERIES IMPROVED TOW VEHICLE

The M901-series improved TOW vehicle (ITV) is a one-vehicle weapon system (Figure 4-1). The M901 employs the M220A1 TOW and the M901A1 employs the M220A2 TOW 2. The ITV is manned by a four-man crew--the squad leader, the gunner, the loader, and the driver.

Section I. INDIVIDUAL DUTIES AND RESPONSIBILITIES

The four-man TOW crew consists of the squad leader, gunner, loader, and driver. The duties and responsibilities of each crew member are discussed in the following paragraphs and in Tables 4-1 through 4-7 below.

4-1. SQUAD LEADER

The squad leader is responsible for the combat readiness and tactical employment of his squad. This includes crew discipline, health and welfare, training, and maintenance of equipment and weapons. Other specific duties include--

• Detecting and identifying targets.
• Issuing fire commands.
• Controlling fire and movement.
• Supervising and assisting in the dismounting and assembly of the M220A1/A2 TOW launcher.
• Employing the squad according to the orders of the section leader.
• Selecting the squad's primary, alternate, and supplementary firing positions for the ITV and, when necessary, for the tripod-mounting of TOW/TOW 2.
• Operating the SLP.
• Requesting squad resupply.
• Keeping the section leader informed of events that affect the tactical situation and the status of the crew.
• Helping the loader boresight the daysight tracker.
• Planning and controlling the fire of the M60 machine gun.
• Carrying the tripod, batteries, and coolant cartridge cases for the nightsight (basic TOW), the tripod and BPC (TOW 2), and binoculars (both systems) when employing the TOW in the ground mode.
• Acting as a gunner and helping raise the side armor, when needed.
• Conducting the system check-out procedures with the aid of the gunner and loader.
• Establishing local security.
• Assisting in determining if a target can be engaged.

4-2. GUNNER

The gunner's duties include--

• Assisting in system check-out procedures.
• Acquiring, recognizing, and identifying armored vehicles using the ITV daysight tracking system.
• Determining if a target can be engaged.
• Engaging targets.
• Recognizing and eliminating a firing angle limitation.
• Helping conduct the turret operational checks.
• Helping the loader collimate the nightsight.
• Removing and carrying the MGS (with battery assembly) and the launch tube when the TOW/TOW 2 is used in the ground mode.
• Stowing the M60 machine gun and closing the gunner's hatch, when required.
• Firing the M60 machine gun when directed to do so by the squad leader.
• Preparing range cards for the TOW and the M60 machine gun.
• Maintaining the M220A1/A2 TOW components, the gunner's weapon station, and the M60 machine gun.

4-3. LOADER

The loader's duties include--

• Inspecting and stowing the encased missiles.
• Preparing missiles for loading.
• Loading the launcher.
• Helping the gunner collimate the nightsight.
• Helping the squad leader boresight the daysight tracker.
• Removing and carrying the traversing unit, the collimator, and an encased missile when the TOW/TOW 2 is used in the ground mode.
• Raising the side armor and lowering the cargo hatch.
• Helping the driver camouflage the vehicle.
• Helping the driver clear the carrier's top deck before the launcher is erected.
• Manually erecting the launcher, when necessary.
• Maintaining the communications equipment.
• Checking the backblast area.
• Removing a misfired missile from the launcher.

4-4. DRIVER

The driver's duties include--

• Maintaining the carrier with the crew's help.
• Driving the carrier tactically (performing evasive maneuvers, fording the carrier, and positioning the carrier in a firing position).
• Camouflaging the carrier and the firing position (with the loader's help) before the launcher is erected.
• Securing all radio antennas.
• Installing the daysight tracker and nightsight on the ITV.
• Helping the loader stow missiles on the missile rack.
• Manning the M60 machine gun when the TOW/TOW 2 is in the ground mode.
• Removing and carrying the daysight tracker and nightsight when the TOW/TOW 2 is in the ground mode.
• Carrying an encased missile (if needed) when the TOW/TOW 2 is used in the ground mode.
• Positioning the ITV in a covered and concealed position when the TOW/TOW 2 is in the ground mode.

Section II. OPERATION PROCEDURES

Before using the M901-series dual launcher, install the M220-series TOW launcher and encased missiles and prepare the M901 for TOW firing.

4-5. CHARACTERISTICS

The M901-series ITV has a high first-round hit probability with a rapid engagement rate. It provides the crew and weapon system protection from small-arms fire and artillery fragments. The squad leader has about a 270-degree range of view through the squad leader's periscope (SLP), which enhances the ITV's capability to operate from concealed and full-hull defilade 270-degree range of view through the squad leader's periscope (SLP), which enhances the ITV's capability to operate from concealed and full-hull defilade positions. The turret launcher has the capability for day and night acquisition and tracking of targets, and it provides firing coverages of 360 degrees in azimuth and +35 to -30 degrees in elevation. The ITV has stowage provisions for tripod-mounted TOW components configured so the ground system can be dismounted and set up in three to five minutes. In addition, the ITV can ford small bodies of water (40 inches or less) and is air transportable. It has the following characteristics"

• A complete M220-series TOW weapon system stowed and strapped in fixed mounting brackets. The daysight tracker and nightsight (AN/TAS-4 or AN/TAS-4A) are mounted in an operational ready state.
• A dual TOW missile launcher.
• M243 smoke grenade launchers.
• A 3X acquisition sight with a 25-degree field of view.
• Remote actuators that allow daysight tracker and nightsight adjustments.
• An M60 machine gun mounted on a traversing rail.
• A hydraulically and electrically powered turret that can be operated manually.

4-6. INSTALLATION OF AN M220-SERIES TOW LAUNCHER AND ENCASED MISSILES

To install an M220-series TOW launcher and encased missiles on an M901-series ITV, see TM 9-2350-259-10.

4-7. PREPARATION OF AN M901-SERIES ITV FOR TOW FIRING

At no time should the turret be placed into operation without performing the operational checklist (Table 4-6).

a. Erect Launcher from a Stow Position (Gunner). Before erecting the launcher, the gunner ensures that the top deck in front of the gunner's station is clear. He locks the M60 machine gun and pintle mount in the stow position and closes the gunner's hatch. He ensures the TURRET POWER switch is OFF. Before starting the engine, the driver turns off the radio. He then turns the master switch ON and starts the engine. He checks the driver's instrument panel and idles the engine at 1,200 to 1,500 rpm. Before the turret power is applied, the gunner checks the gunner's control panel and ensures the switches are as shown in Figure 4-2.

DANGER To avoid injury to personnel and damage to equipment, clear the top deck of personnel and loose objects.

NOTE: The launcher can be erected by using battery power, but the vehicle's engine should be started to avoid draining the batteries. When operating the launcher using battery power, the driver monitors the battery generator indicator on the driver's instrument panel. If the indicator needle is in the red section while the turret is operating, the driver stops operations and starts the engine. (The driver turns the emergency power switch ON in case a power surge disengages the 5-ampere fuze.) After starting the engine, he idles it at 1,200 to 1,500 rpm. He turns the emergency power off after the engine starts.

(1) The gunner turns the TURRET POWER switch to the ON position. AZ STOW, ELEV STOW, and STOW POSITION indicators will be on.

(2) The gunner turns the MODE SELECT knob to ERECT (Figure 4-3). He pushes up on the ERECTION DRIVE switch and holds it in the ON position until--

• LAUNCHER ERECT and LAUNCHER READY lights are on.
• AZ STOW and ELEV STOW lights remain on.
• STOW POSITION indicator light is off.

LAUNCHER ERECT and LAUNCHER READY lights will only come on after the launcher is erected and locked in position.

b. Prepare a Dual Launcher for Loading (Gunner).

WARNING Do not operate gunner's hand controls (GHCs) unless both the LAUNCHER ERECT and LAUNCHER READY indicators are on. If the indicators are not on, the launcher could fall, resulting in serious injury to personnel and damage to equipment.

(1) To traverse the turret (Figure 4-4), the gunner squeezes the action and slew switches and rotates the GHC counterclockwise until the turret azimuth indicator reads almost 0 degrees. The AZ LOAD indicator will light (Figure 4-4).

(2) To elevate the launcher, the gunner squeezes the action switches and rotates the GHC backward elevating the launcher to maximum elevation. The ELEV LOAD indicator will light.

(3) To place the launcher in the load position, the gunner moves the MODE SELECT knob to LOAD. He holds the ERECTION DRIVE switch to ON until the LOAD POSITION indicator lights and the LAUNCHER ERECT and LAUNCHER READY indicator lights are OFF, then releases the switch. The READY TO LOAD light on the fire interrupt/intercom assembly will also be on, indicating to the loader to proceed with loading the launcher.

c. Load a Dual Launcher and Return to Stow Position (Loader). Before loading the launcher, the loader ensures the READY TO LOAD indicator is lit.

(1) The loader opens the cargo hatch to the first detent. He secures the encased missile and places indexing lugs on the launcher rail and slides the missile forward until the front of the missile seats against the forward centering ring. He holds the missile in place while pulling down the locking handle (Figure 4-5). (He repeats the procedure for the other missile if two missiles are to be loaded.) The loader closes the cargo hatch by releasing the cargo hatch detent lock lug and pulling down on the cargo hatch strap.

(2) Once the launcher has been loaded, the gunner moves the MODE SELECT switch to ERECT. He pushes the ERECTION DRIVE switch up and holds until the LAUNCHER ERECT, LAUNCHER READY, AZ LOAD, and ELEV LOAD indicators are lit. Then, he traverses the turret to about 180 degrees (the AZ STOW indicator light should come on) and depresses the launcher until the ELEV STOW indicator lights. He moves the MODE SELECT switch to STOW and pushes the ERECTION DRIVE switch up and holds it. The STOW position indicator will light when the launcher is in the stow position (at this time the LAUNCHER ERECT and LAUNCHER READY indicators should be off); if the indicator lights go off, the gunner erects the launcher and repeats the stowing procedures. Once the launcher is in the STOW position, the gunner moves the TURRET POWER switch to OFF.

CAUTIONS 1. Ensure the missile is fully seated against the front of the launch tube before engaging the missile locking handle. If abnormal force (greater than 30 pounds) is required to lock the missile locking handle, place the locking handle in the unlocked position and reseat the missile, ensuring it is fully seated against the front of the launch tube. Raise the missile up firmly against the launcher guide rails and attempt to place the missile locking handle to the locked position. If abnormal force is still required to lock the missile locking handle, remove the missile and inspect it for damage. If the missile is damaged, discard it and load a serviceable missile into the launch tube. If the missile is not damaged, notify organizational maintenance. Failure to observe this caution may result in damage to the system. 2. Never elevate the turret to get the ELEV STOW light to come on. This will damage the turret when stowing.

4-8. TARGET ENGAGEMENT

The crew performs the following procedures to engage a target.

a. The gunner erects the launcher from the stowed position.

b. The gunner turns the SELECT switch to 3X (Figure 4-6A). In response to the fire command (Table 4-1) he tracks the target by rotating the turret in the direction of the target.

(1) The gunner grasps both GHCs while squeezing one or both action switches and turning the GHC assembly clockwise to rotate the turret to the right or counterclockwise to rotate the turret to the left.

(2) If speed is desired, the gunner presses one or both slew switches (increasing the speed four times).

(3) The gunner elevates or depresses the launcher with either one or both GHCs.

(4) The gunner rotates the GHC and pushes forward (while squeezing the action switch) to depress the launcher; he rotates the GHC and pulls back to elevate the launcher.

c. The gunner centers the reticle on the target. He turns the SIGHT SELECT switch to 13X (line of sight to target is now through the daysight tracker [Figure 4-6B]). He turns the SIGHT SELECT switch to NIGHT and pulls the field of view selector all the way out. (The target is now seen through the nightsight in the narrow field of view mode [Figure 4-6C].) The cross hairs and the rectangular sight picture are illuminated providing a close-up picture of the target. The gunner adjusts the brightness, contrast, and range focus controls to get the best possible target image. For the M901A1, the gunner uses the following procedures.

(1) He locates the target using the daysight tracker, but fires using the nightsight. Smoke, dust, and so forth can obscure the battlefield even during daylight. The nightsight allows continuous observation of the target regardless of battlefield visibility conditions. During limited visibility, the gunner uses the nightsight for target location and engagement. When firing the TOW 2 system, he always turns the nightsight ON, regardless of which sight is used, to ensure that the enhanced capabilities of the TOW 2 are used during firing, flight, and impact.

(2) Certain conditions may permit degraded firing. If, during the system check-out procedure, the MGS display indicates a nightsight (postamplifier) failure and that is the only failure indicated, the gunner can still fire the TOW 2 using the daysight tracker. However, if limited visibility conditions cause a handoff to the nightsight during flight, control of the missile may be lost.

WARNING Do not operate the GHCs unless both LAUNCHER ERECT and LAUNCHER READY indicators on the gunner's control panel are on. If the indicators are not on, the launcher could fall, resulting in serious injury to personnel and damage to equipment.

d. The gunner selects a missile by turning the MISSILE SELECT switch to the left or to the right (depending on which missile is to be fired). He places the ARMED-SAFE switch to ON while keeping the cross hairs on the target. He looks for LEFT SELECT and LEFT ARMED lights or RIGHT SELECT and RIGHT ARMED lights to light up on the control panel (depending on which missile is to be fired). He fires the missile by pressing either or both TRIGGER switches and keeps tracking the target until the missile impacts. If the trigger light does not light up immediately, he presses both TRIGGER switches again. (A 1.5-second delay normally occurs between the time the TRIGGER switch is pressed and the missile is launched.) If the missile does not fire 1.5 seconds after the trigger is pressed, the missile is treated as a misfire. The gunner selects the second missile to engage another target.

4-9. IMMEDIATE ACTION

The crew performs immediate action procedures as described in Table 4-2 to eliminate the malfunction, and they continue the mission in the fastest and safest manner.

4-10. RELOADING

The crew performs the following procedures to reload the TOW/TOW 2 on the M901-series.

a. The gunner notes the turret deflection of the target area so he can quickly return to the target after reloading. He moves the launcher to the load position. When the LOAD POSITION light comes on, he announces, "Ready."

b. The loader unstraps and prepares two missiles in the storage rack (positions 9 and 10). He places one of the missiles on the carrier floor and watches the READY TO LOAD light while listening for the gunner to announce "Ready." When the gunner announces, "Ready," and the READY TO LOAD light is on, the loader opens the cargo hatch to the first stop position. He unlocks the left launch tube locking handle (UP is unlocked) and removes the expended missile case. He throws the expended missile case out of the carrier over the left side. He loads the missile that is on the carrier floor by placing the missile's indexing lugs on the left launch tube guide rails and sliding the missile forward until it slips into the centering ring at the front of the launch tube. He supports the missile with the heel of his left hand to keep from puncturing the missile diaphragm with his fingers. He locks the left launch tube locking handle (DOWN is locked). He follows the same procedures for reloading the right launch tube except all left-handed actions will be right-handed actions. He slams the hatch closed, announces, "Up," and moves two more missiles to the ready rack.

c. The gunner rotates the MODE SELECT switch to the ERECT position and watches the gunner's control panel. When the fire interrupt and cargo hatch lights go off, he holds the ERECTION DRIVE switch up. When the LAUNCHER READY light comes on, he slews the launcher to the proper deflection, depresses the launcher until a target is seen, and announces, "Identified."

NOTE: The squad leader may require the loader to observe the backblast area.

4-11. EMERGENCY ACTION

The crew performs the following emergency action procedures.

a. After the gunner commands, ERECT THE LAUNCHER MANUALLY, the squad takes these actions.

(1) The gunner--

(a) Sets the EMER PWR switch to the UP position.

(b) Sets the MODE SELECT switch to the ERECT position. Loosens the strap securing the hydraulic pump handle. (If the TURRET POWER switch is ON, turning it OFF is not necessary.)

(c) Slides out of the gunner's seat to allow the squad leader room to pump up the hydraulic pressure. (The gunner should not pump the hydraulic hand pump unless absolutely necessary. Fatigue that results from pumping may affect his tracking ability.)

(d) Sits in the squad leader's seat and observes the battlefield through the SLP.

(e) Moves back to the gunner's seat and slews the turret to observe the battlefield and engage targets (after the squad leader has pumped the hydraulic pressure to 1,400 pounds per square inch [psi] and the launcher is erected and locked).

(2) The squad leader--

(a) Stands up and leans into the gunner's station after the gunner leaves.

(b) Pumps the hydraulic pump handle as the loader cranks the launcher to the erect position (maintains at least 1,400 psi).

(c) Returns to the squad leader's seat when the launcher is erect and locked in place. (The erection locks can be heard driving into place and the LAUNCHER ERECT and LAUNCHER READY lights on the gunner's control panel will come on.) Secures the hydraulic pump handle with a strap before returning to the squad leader's seat.

(3) The loader--

(a) Gets the handcrank from the driver, exits the carrier through the crew door in the rear ramp, climbs to the top of the carrier, and moves to the right side.

(b) Locates the access cover on the launcher erection arm and unscrews it. (The access cover is attached to the launcher erection arm with a chain.)

(c) Inserts the handcrank as far as it will go into the hole in the erection arm. Turns the handcrank until the launcher is erect and the upper locks engage.

• If the crank is hard to crank, it may not be inserted all the way or the emergency power battery may be discharged.
• Slow down as the launcher nears the erect position to be sure the upper locks engage and do not move past the erect position.

(d) Removes the handcrank, replaces the access cover, and returns to his on-carrier position.

b. The squad follows alternate procedures for erecting the launcher with backup power.

(1) The gunner--

(a) Sets the EMER PWR switch to the UP position and the MODE SELECT switch to the ERECT position. (TURRET POWER does not have to be turned off.)

(b) Loosens the strap securing the hydraulic pump handle, moves to the squad leader's seat, and observes the battlefield through the SLP.

(c) Returns to the gunner's seat when the launcher is erect and traverses the turret to observe the battlefield and engage targets.

(2) The squad leader--

(a) Takes turns with the loader pumping the hydraulic pump until the pressure gauge reaches 1,750 psi or higher; then holds the ERECTION DRIVE switch UP.

(b) Releases the ERECTION DRIVE switch when the LAUNCHER ERECT and LAUNCHER READY lights come on.

c. The squad acquires and engages targets using emergency power.

(1) The gunner--

(a) Ensures the launcher is erect and traversed to approximate deflection to target.

(b) Ensures the hydraulic pressure is at least 1,200 psi and EMER PWR switch is up (ON).

(c) Tells the squad leader or loader to pump up the hydraulic pressure as required. (Do NOT pump when tracking a target--tracking will be jerky.)

(d) Acquires the target using the 3X telescope.

(e) Switches to the 13X daysight tracker when the target has been acquired and fires the missile. Tracks the target until missile impact.

(2) The squad leader and loader switch back and forth pumping up hydraulic pressure when the gunner requests. (The loader should be the primary pumper because the squad leader needs to observe the battlefield.)

d. The squad reloads the dual launcher during an emergency.

(1) The primary method of reloading the dual launcher in an emergency is for the loader to exit the carrier through the cargo hatch and reload the launch tubes with the launcher still in the erect position. The squad leader hands the missiles to the loader.

(2) An alternate method of reloading the dual launcher in an emergency is for the squad leader (or loader, only if absolutely necessary) to pump up hydraulic pressure as directed by the gunner. The gunner ensures the hydraulic pressure is at least 1,750 psi before moving the launcher from the erect position to the load position and back to the erect position from the load position. He directs the squad leader or the loader to pump up hydraulic pressure when necessary.

(3) All other procedures are the same as for a normal reload.

e. The squad stows the launcher using emergency power.

(1) The squad leader or the loader pumps up hydraulic pressure as directed by the gunner.

(2) The gunner ensures the hydraulic pressure is at least 1,750 psi before moving the launcher from erect to stow. He directs the squad leader or the loader to pump up hydraulic pressure when necessary.

(3) When the stow position light comes on, the gunner secures the hydraulic pump handle with the securing strap.

(4) All other procedures are the same as for a normal stow.

4-12. DISMOUNT AND REMOUNT

During the operation of the ITV, the TOW may have to be dismounted from the carrier and used tripod-mounted to engage the enemy--for example, during vehicle electrical failure, during mechanical failure, if the vehicle is disabled from indirect fire, if the sector of fire cannot be covered while mounted, or on the command of the section or squad leader. Once the mission has been completed from the tripod-mounted mode, a secondary mission may require remounting the carrier and moving to a different firing position. (See Tables 4-3 and 4-4 for the dismount and remount procedures for an M901-series.)

4-13. EVACUATION

In case of fire, the crew evacuates by performing the following:

a. The driver opens the driver's hatch and exits the vehicle.

b. The gunner opens the gunner's hatch and exits the vehicle.

c. The squad leader follows the gunner out the gunner's hatch. Once outside, the squad leader pulls the fixed fire extinguisher handle.

d. The loader exits the carrier the fastest way possible through either the gunner's or driver's hatches. The gunner's hatch is usually the best, but if that is blocked by either the gunner or squad leader, the driver's hatch may be faster.

4-14. M60 MACHINE GUN OPERATION

The secondary weapon for the M901-series is the M60 machine gun. It is used for security of the vehicle and crew.

a. Mount, Stow, and Dismount Procedures.

(1) Mount the machine gun and pintle. Place the machine gun pintle in the socket of the pintle mount. Tighten the pintle mount locking handle on the side of the socket. Rotate the pintle to ensure it does not bind and rotates freely. Place the M60 machine gun on the machine gun mount and check the front mounting lug to ensure it is engaged in position inside the mounting recess. Lower the butt of the gun on the machine gun mount until the mounting latch engages the rear locking pin. The gun should snap in place.

(2) Stow the machine gun. Push the pintle mount frame to the right side of the traversing rail and lock it in position with the traversing rail lock. Push the butt of the gun down into the travel lock receiver. The travel lock is spring loaded and should automatically lock the gun in the raised position.

CAUTION Make sure the gun is in the stow position when operating the turret.

(3) Dismount the machine gun. Release the travel lock on the pintle mount and pull the butt of the gun up. Release the machine gun from the stow position and tilt the weapon so the muzzle is pointed downward. Release the mounting latch; push it forward and pull up on the weapon at the same time.

b. Target Engagement Procedures.

(1) Sight and aim. When firing an M60 machine gun mounted, the sights are not used. Look over the top of the weapon and adjust the fire to the target by the strike of the bullets on the ground or by the tracer path.

(a) To engage linear targets (Figure 4-7), engage the entire width of the target. Lay the gun on the center of mass, or portion of the target that presents the-greatest threat. Traverse the fire to either flank, then cover the remainder of the target.

(b) To engage linear target with depth (Figure 4-8), engage the entire width and depth of the target. Lay the gun on the center of mass, or portion of the target that presents the greatest threat. Traverse and search to the flank closest to the position, then cover the entire target.

(c) To engage deep target (Figure 4-9), engage the entire target depth. Lay the gun on the center of mass, or portion of the target that presents the greatest threat. Search to the portion of the target nearest the position, then the entire target.

(d) To engage moving targets (Figure 4-10), apply correct lead on a moving target. Place the point of aim far enough in front of the target so the fire and the target meet.

(2) Observe fire. Observe either the dust raised by the strike of the round, or the tracers, and make an adjustment to bring the fire onto the target.

(3) Adjust fire. When the strike of the rounds is observed, or tracers are going high over the target, immediately cease fire and start over again.

4-15. SQUAD LEADER'S PERISCOPE OPERATION

The SLP can be used to help detect targets and determine the range to them. It has a possible 270-degree field of view. However, depending on the position of the launcher, the field of view may be less than 270 degrees.

a. Description. The parts of an SLP are a humidity indicator, a focus control ring, the eye cup, the reticle, an azimuth control knob, and an elevation control knob (Figure 4-11).

(1) The humidity indicator contains replaceable desiccant. DA Form 2404 is used to report when the desiccant shows pink.

(2) The focus control ring is directly behind the eye cup. The squad leader turns the focus ring while looking through the SLP to properly focus the image.

(3) The eye cup is an inflated rubber eye protector to protect the eye during use of the SLP.

(4) The SLP reticle is a nonmoveable azimuth scale in degrees. Zero is always to the front of the vehicle. As the SLP is rotated, the azimuth indicator is rotated around the azimuth scale to indicate the direction to the target in relation to the vehicle. Four stadia lines, located in the center of the reticle, are used to compute the estimated range to targets.

(5) The azimuth control knob rotates the SLP in azimuth. The squad leader turns the knob clockwise to rotate the line of sight to the left. (Three rotations of control knob causes the line of sight to rotate 360 degrees in azimuth.)

(6) The elevation control knob is rotated clockwise to raise the line of sight and counterclockwise to lower the line of sight. The full range of motion is 10 degrees above horizontal and 20 degrees below horizontal.

b. Use of the SLP. The squad leader places his eye against the eye cup and presses firmly to look through the periscope. He focuses the SLP by adjusting the focus controls for a clear image of an object at the edge of the field of view. He turns the azimuth control knob clockwise or counterclockwise to search the area for enemy activity. He turns the elevation knob clockwise or counterclockwise to raise or lower the line of sight of the SLP. If a target is detected, he looks at the azimuth scale, reads the degrees under the azimuth indicator, and relays the reading to the gunner.

c. Target Range Determination. The SLP can be used to determine the range to a target.

(1) The squad leader places the stadia lines (Figure 4-12) on the target and determines how wide the target is in mils. Within the periscope reticle are four stadia lines. The distance between the two center lines is 3 mils; the distance between the two outer lines is 8 mils.

(2) To determine the estimated range to the target, the squad leader uses the following formula:

ES--Estimated size of target (meters).
AS--Apparent size of target (mils).
1,000--Base number used to compute all ranges to targets.

ES x 1,000 = Estimated range
      AS

For computing range, all tanks are considered to be 6 meters long (viewed broadside) and 3 meters wide (viewed head-on).

EXAMPLE: A 6-meter-long tank (viewed broadside) bounded by the inner stadia lines (3 mils).

3 x 1,000 = 3,000 = 1,000
   3                  3

Range to target is estimated to be 1,000 meters.

(3) Using Table 4-5 above, the squad leader locates the estimated size of the target (meters) on the left side of the table and the apparent size of the target (mils) along the bottom of the table. He looks across the table on the meter line and up on the mil line until they meet. At the point where the lines meet is the estimated range to target.

EXAMPLE: A 6-meter-long tank, bounded by the outer stadia lines (8 mils). Using the table, go across from 6 meters and up from 8 mils. The figure found, 750, is the estimated range to the target in meters.

(4) A tank at 3,000 meters viewed head on is 3 meters wide (Figure 4-13); viewed broadside it is 6 meters long (Figure 4-14). To determine if target is in range, the target must appear the same size or larger. If a determination cannot be made, the squad leader has the gunner use the daysight tracker or nightsight to determine if the target is in range.

4-16. M243 SMOKE GRENADE LAUNCHER OPERATION

The following paragraphs explain how to load, fire, and conduct misfire procedures when using the M243 smoke grenade launcher.

WARNING 1. Do not stand in front of a loaded grenade launcher. 2. Do not place any part of the body in front of the launcher while loading or unloading.

a. Load Grenade Launcher. The gunner places the grenade launcher ARM-OFF switch in the OFF position and ensures the power lamp is not on (Figure 4-15). The loader removes the rubber cover from the tubes and ensures that the tubes are free of foreign objects. The loader inserts a smoke grenade into each tube and pushes down on the grenade's top so that the spring clip at the base of each grenade engages the tip plug at the bottom of each tube. He rotates each grenade about a half turn clockwise to ensure electrical contact.

WARNING Before firing, make sure no obstacles are directly in front of the vehicle.

b. Fire the Smoke Grenades. Eight grenades detonate in about a 105-degree arc 30 meters from the vehicle. The smoke cloud is about 9 meters high and lasts about one to three minutes, depending on wind (Figure 4-16). The front of the vehicle is facing the area where the smoke is to conceal the movement of the vehicle. The gunner places the smoke launcher ARM-OFF switch to ARM. He presses the FIRE button when ready to fire.

WARNING Do not remove misfired grenade under unloading procedures. Use procedures for misfire.

c. Perform Misfire Procedures. If a grenade fails to fire, the gunner makes two more attempts to fire it. If the grenade still does not fire, the gunner ensures that the ARM-OFF switch is OFF and the power lamp is not on. The loader ensures the grenade is firmly seated. If the grenade is not firmly seated, the loader loads it properly. The gunner positions the ARM-OFF switch to ARM and attempts to fire the grenade, If the grenade will not fire when firmly seated, the crew attempts to fire the grenade from another launch tube. If the grenade fires, organizational maintenance is notified of a defective launch tube. If the grenade still does not fire, it is treated as a dud.

WARNING In a training situation, do not attempt to move a dud grenade. If a grenade fails to ignite after being launched, wait 15 minutes; then notify EOD personnel. Give type, quantity, and precise location of dud.

4-17. FIRING LIMITATIONS

Firing limitations for the M901-series mounted TOW/TOW 2 are the same as for the tripod-mounted TOW/TOW 2.

4-18. OPERATIONAL CHECKLIST AND TROUBLESHOOTING FOR M901-SERIES

The operational checklist (OCL) and troubleshooting table are supplements to the TM. They do not replace the TM or scheduled PMCS. The TM must be used when correcting or reporting faults.

a. An OCL should be performed before placing the turret of the M901-series into operation (Table 4-6) if the tactical situation does not permit PMCS. Each procedure in the checklist is important to the operational readiness of the vehicle.

b. To perform an OCL, the operator must also know how to troubleshoot the system. Some of the more frequent faults that may occur and the corrective action to be taken to correct the fault are listed in Table 4-7. If a fault is found, refer to the TM.

c. The operator must remember to check the weapon system before installing it on the vehicle--daily, once it has been installed, and weekly, when it is not in use. In addition to checking the boresight during check-out procedures, check it--

• After difficult cross-country movement.
• After a change in temperature of 10 degrees.
• Every four hours.