1. Define the four types of adjustment techniques.
2. Determine the correct adjustment in successive bracketing, given a situation.
3. Identify the situation for which you would use hasty bracketing.
4. Identify when you may use the one round adjustment method, given a situation.
5. Identify a situation for which you need to use the creeping fire method.
6. Determine when the "ping-pong effect" may affect adjustments.
7. Determine the proper time to enter the fire for effect phase of the mission.
8. Determine the results of the FFE, given a situation.
9. Determine the proper commands to request additional fires.
10. Identify the proper procedure for ending the mission.
3401. Adjustment Techniques
There are four techniques that can be used to conduct area adjustment fires. These are successive bracketing, hasty bracketing, one-round adjustment, and creeping fire.
a. Successive bracketing. Successive bracketing is best for an inexperienced observer or when precise adjustment is required, such as for precision registrations and destruction missions. This method mathematically ensures that FFE rounds will be within 50 meters of the target.
b. Hasty bracketing. Hasty bracketing is best for an experienced observer when responsive fires are needed.
c. One-round adjustment. One-round adjustment provides the most responsive fires but requires an experienced observer or an observer equipped with a laser rangefinder.
d. Creeping fire. Creeping fire is used for danger close missions. Upon completion of each
3402. Successive Bracketing
After the first definite range spotting (either over or short) you send a correction to establish a bracket (one round over and one round short). Once a bracket is established, you successively split this bracket in half in multiples of 100 meter increments. Normally, you would start with an ADD (or DROP) 400 and split that in half on the next round DROP (or ADD) 200. Next, split that again ADD (or DROP) 100. Once you have a 100 meter bracket the next split will
mathematically put the round within 50 meters of the target so you would send ADD (or DROP) 50, FIRE FOR EFFECT, OVER. You may start with an 800 meter bracket if you need to; but if your first correction is large, this could indicate an error in your OT factor. Remember, range corrections should be 800, 400, or 200 so they can be split in even 100 meter increments.
Example: The first round after your call-for-fire is spotted as OVER, 80 LEFT. Your OT factor is 2. The first correction you should send would be RIGHT 160, DROP 400, OVER. You spot the next round as SHORT, 15 RIGHT. The correction for this round would be LEFT 30, ADD 200, OVER. You spot the round as OVER, 5 LEFT. The correction would be DROP 100, OVER. You spot the round as OVER, 5 LEFT. The correction would be DROP 50, FIRE FOR EFFECT, OVER.
3403. Hasty Bracketing
Experience has shown that effectiveness on the target decreases as the number of rounds used in adjustment increases. This is due to the loss of surprise. An alternative to successive bracketing is hasty bracketing. If the nature of the target dictates that fires are needed in less time than successive bracketing would take, you need to use hasty bracketing. The success of hasty bracketing depends on a thorough terrain analysis to give you an accurate initial target location.
You make a bracket with your first correction and use this as a yardstick to determine your next correction. You then send the correction and FIRE FOR EFFECT.
Example: Your initial round impacts over the target. You spot it as OVER, 40 RIGHT.
Your OT factor is 3. You send a correction of LEFT 120, DROP 200, OVER.
The next round is spotted as SHORT, 10 LEFT. You now have a 200 meter bracket. From your spotting you determine the first round was twice as far from the target as the last round, so you send RIGHT 30, ADD 50, FFE, OVER. This puts you within 50 meters of your target.
Example: Your initial round impacts short of the target. You spot it as SHORT, 35 LEFT. You had estimated the target to be 1200 meters. By using
flash-to-bang, you have determined the burst to be 1100 meters (you don't have a MULE or AN/GVS-5). Your correction would be RIGHT 30, ADD 100, FIRE FOR EFFECT, OVER.
3405. Creeping Fire
Creeping fire is used only during Danger Close missions. You make range corrections of 100 meters, or less, to "creep" the rounds onto the target so you don't endanger friendly positions.
You must know the location of friendly positions in relation to your target. Their safety is your responsibility! All guns that will fire the FFE phase will also fire during adjustment when you use creeping fires.
3406. Effects on Adjustments
You have learned that the FDC will, or should, notify you if the Angle-T is greater than 500 mils or if the probable error in range (PE/R) is 38 meters or greater. They should inform you of this as it could have an effect on your adjustment.
a. Angle-T. Angle-T is the angle formed at the target by the intersection of the observer target (OT) line and the gun target (GT) line (fig 3-5).
When the Angle-T is small, your deviation and range corrections correspond to the firing unit's deviation and range corrections. When the Angle-T is greater than 500 mils, your deviation corrections become the firing unit's range corrections and your range corrections become their deviation corrections. This has a significant effect on your adjustment. When notified that the Angle-T is greater than 500 mils, you should continue making corrections in the usual manner until they are not having the proper effect (for example, a right 200 correction appears to shift right 300). You must adjust your corrections proportionately to compensate (cut your corrections in half or thirds) for this error.
Note: When Angle-T is greater than 500 mils, you will observe PE/R as part of deviation spotting. You may expect to observe a ping-pong effect, anytime that the Angle-T is 500 mils or greater. When PE/R of 38 or greater and Angle-T is 500 mils or greater are combined, you will see a pronounced
ping-pong effect. To minimize the effect on your adjustment, you can cut your deviation corrections or you can request two guns adjust to get an average of the spotting.
b. Dispersion and PE/R. Dispersion is the term for the fact that no two rounds will impact exactly in the same spot, even though they are fired from the same tube with identical powder, projectile, data, etc. The FDC measures dispersion in units called probable errors. If you were to fire 100 identical rounds from the same howitzer with the same data, same weather conditions, etc., the rounds would impact in an elliptical pattern similar to the illustration in figure 3-6.
line. They announce the PE/R to prevent you from attempting to correct the impact caused by natural dispersion.
3407. Fire for Effect
The purpose of area fire is to cover the target area with fire so the greatest effects on the target can be achieved. The type and amount of ammunition you have requested depends on the type of target, its posture, and its activity. The fire for effect phase of an adjust fire mission is entered when the deviation, range, and height of burst (if necessary) have been corrected to provide effects on target. This would be when the adjusting round has effects on target, or when splitting a 100 meter bracket, or when splitting a 200 meter bracket if the PE/R is 38 or greater.
Remember, you will be adjusting with HE/Quick (unless you requested something else) for deviation and range. You enter the fire for effect stage by giving your corrections and announcing FIRE FOR EFFECT.
If you have requested, or the FDC informed you that you will receive time in effect, you must adjust the height of burst before requesting FFE. When you split the 100 meter bracket, you request TIME, ADD (or DROP) 50, OVER. Then you adjust HOB. After you receive time, you do not make any more range or deviation corrections. Once you receive a measureable airburst, you send any correction necessary to achieve a 20 meter HOB and request FFE. For example, your last correction was TIME, ADD 50, OVER. You spot the next round as AIR 20, with an OT factor of 2. You would send DOWN 20, FIRE FOR EFFECT, OVER. You do not have to fire for effect from a graze burst or if the HOB correction is greater than 40 meters.
3408. Obtaining Additional Fire
After you fire for effect, you may determine that additional rounds are needed on the same or different location. If your FFE was on target, but additional rounds are needed, announce REPEAT, OVER. If the location of fire needs to be moved to achieve satisfactory results, you announce the appropriate corrections and REPEAT. For example, RIGHT 40, ADD 100, REPEAT, OVER.
3409. End of Mission (EOM)
After all rounds have landed, there are two things you must do. First you must decide what class of FFE was achieved, then you must take action on it. The action you take is easily remembered by the acronym RREMS. RREMS stands for refinement, record as target, end of mission, and surveillence. Refinement is the final corrections needed to move the mean point of impact onto the target. Record as target is sent when you want the FDC to retain the target's plot for future use as a point to shift from. End of mission is transmitted to end the fire mission. Surveillance is
a. Accurate and sufficient. This means that the mean point of impact of the rounds were on target and the volume of fire was sufficient to have the desired effect. If you want the FDC to record the target, announce RECORD AS TARGET, END OF MISSION, 2 BRDM'S
DESTROYED, ESTIMATE 6 CASUALTIES, OVER. If you don't want the target to be recorded, omit RECORD AS TARGET.
b. Inaccurate but sufficient. This means the volume of fire was sufficient but the mean point of impact was not on target. You must give refinement before ending the mission. For example, if you spot your fire for effect as RANGE CORRECT, 10 RIGHT and your OT factor is 2, you would send LEFT 20, END OF MISSION, TARGET NEUTRALIZED, ESTIMATE 10 CASUALTIES, OVER. If you want to record as a target, announce RECORD AS TARGET after the refinement and before the end of mission.
c. Inaccurate and insufficient. This means that not only was the mean point of impact off the target, but also the volume was not sufficient to have the desired effect on target. You must make corrections onto the target (refinement) and request REPEAT. If this gives the desired effect, you then end the mission and give your surveillence.
d. Accurate but insufficient. This simply requires a REPEAT until the desired effects are achieved.
When ending a fire mission, you must follow the sequence of RREMS to be correct, particularly if you want to record the target. When the FDC hears EOM they clear the computer for the next mission and your mission data is lost. Sending surveillance marks the end of the fire mission and you are ready to engage another target.
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Exercise: Complete items 1 through 10 by performing the action required. Check your responses against those listed at the end of this study unit.
Matching: For items 1 through 4, match the adjusting technique in column 1 with its correct definition in column 2. Place your responses in the spaces provided.
Column 1 Column 2
Technique Definintion
___ 1. Successive bracketing a. Will not attempt to establish a bracket ___ 2. Hasty bracketing b. The best method for an experienced
___ 3. One round adjustment observer
___ 4. Creeping fires c. The best method for an inexperienced observer d. Pick an alternate aiming point and adjust with corrections of 100 meters or less
Situation: You spot the initial round as SHORT, 10 RIGHT. You have estimated the range to the target as 3600 meters. Your OT factor is 4.
5. Based on the above situation, what would your correction be using successive bracketing?
a. LEFT 10, ADD 100 c. LEFT 40, UP 400
b. SHORT, 10 RIGHT d. LEFT 40, ADD 400
6. You are performing creeping fires. The rounds have impacted at an alternate adjusting point and you spot them as RANGE CORRECT, LINE. You have determined the distance to the target as 600 meters. You have determined the distance to the alternate adjusting point as 800 meters. What is your correction?
a. LEFT 100, DROP 250 c. DROP 100
b. DROP 200 d. LEFT 100, DROP 100
7. Which transmission from the FDC would cause you to consider "ping-pong" in your adjustment?
8. In an adjust fire mission, using successive bracketing, you have sent a correction of LEFT 30, DROP 100. The round was fired and you spot the burst as SHORT LINE.
What would your correction be?
a. ADD 50, OVER c. FFE, OVER
b. ADD 50, FFE, OVER d. DROP 50, OVER
Situation: You are conducting an adjust fire mission using hasty bracketing. Your first round was spotted as OVER, 50 RIGHT. You gave a correction of LEFT 100, DROP 200.
Your next spotting was SHORT, 10 RIGHT. You determined the last round was an equal distance short of the target as the first round was over so you send ADD 100, FIRE FOR EFFECT, OVER. You spot the mean point of impact of your FFE rounds as SHORT, 10 RIGHT.
9. What is the result of the fire for effect in the situation above?
a. Accurate and sufficient b. Inacurate and insufficient c. Accurate and insufficient d. Inaccurate and sufficient
10. To end the mission, which should you send?
a. Refinement, record as target, end of mission, and surveillance b. Record as target, refinement, end of mission, and surveillance c. Refine, record, estimate, and repeat
d. Record as target, end of mission, and estimate casualties
UNIT SUMMARY
In this study unit, you learned how to conduct fire missions. You now have the basic knowledge necessary to call for adjusting and reporting the results of fires on target using artillery or mortars.
Lesson 1 Exercise Solutions
Lesson 4 Exercise Solutions
Solution Reference
1. c. 3402a
2. b. 3403
3. a. 3404
4. d. 3405
5. d. 3402
6. c. 3403
7. c. 3406a
8. b. 3402
9. d. 3409
10. a. 3409
BASIC FORWARD OBSERVATION PROCEDURES REVIEW LESSON
INSTRUCTIONS: The purpose of the review lesson is to prepare you for your final examination.
We recommend that you try to complete your review lesson without referring to the text, but for those items (questions) you are unsure of, restudy the text. When you have finished your review lesson and are satisfied with your responses, check your responses against the answers provided at the end of this review lesson examination.
Select the ONE answer which BEST completes the statement or answers the item. For
multiple-choice items, circle your response. For matching items, place the letter of your response in the space provided.
1. Which are the three types of indirect fire support?
a. Naval gunfire, howitzers, close air support b. Howitzers, naval gunfire, mortars
c. Mortars, howitzers, tanks
d. Howitzers, mortars, close air support
Matching: For items 2 through 4, match the type of indirect fire support in column 1 with the characteristics that best describe it in column 2. Selections in column 2 may be used more than once.
Column 1 Column 2
Indirect Fire Support Characteristics
___ 2. Naval gunfire a. Low trajectory, medium artillery, high rate
___ 3. Howitzers of fire
___ 4. Mortars b. Light artillery, high rate of fire, high
trajectory
c. Medium trajectory, medium artillery, massed fires
d. High trajectory, low rate of fire, light artillery
Matching: For items 5 through 7, match the member of the gunnery team in column 1 with the duties that best describe his job in column 2. Selections in column 2 may be used more than once.
Column 1 Column 2
Member Duty
___ 5. Observer a. Coordinates the fires of different
___ 6. Fire direction center supporting arms
___ 7. Firing element b. Locates and identifies targets to the firing unit
c. Receives call-for-fire and translates it into firing data
d. Fires the rounds as directed 8. The duties of the fire support coordinator (FSC) include
a. monitoring command and fire nets to coordinate the fire support assets and use them to their best advantage.
b. instructing observers when to fire targets of opportunity.
c. maintaining radio discipline during fire missions.
d. determining firing data for supporting arms.
9. Marine Corps units designate targets using a. observer target numbers.
b. an assigned block of two letters and four numbers.
c. two numbers and four letters.
d. individual unit designators.
10. What are the two types of targets?
a. Priority targets and targets of opportunity b. On-call targets and scheduled targets c. Planned targets and targets of opportunity
12. A known point is
a. any target with its map location known to the supporting arms.
b. any point on the ground which is known to the supporting arms.
c. any point on the ground or map with its location known to the observer and the FDC.
d. a previously fired target or hill top.
Matching: For items 13 through 15, match the desired effect of artillery fires in column 1 with the definition that best describes it in column 2. Selections in column 2 may be used more than once. After the corresponding item number on the answer sheet, blacken the appropriate circle.
Column 1 Column 2
Effect Definition
___ 13. Destruction a. Target temporarily ceases activity, requires
___ 14. Neutralization high ammunition expense
___ 15. Suppression b. At least 30 percent personnel casualties, requires high ammunition expense c. At least 10 percent personnel casualties,
requires low ammunition expense d. At least 30 percent personnel casualties,
requires minimum ammunition expense 16. What are the five types of artillery shells?
a. HC, FASCAM, ICM, HE, and Illum b. WP, HE, Smoke, Illum, and ICM c. ICM, Smoke, Illum, WP, and HE d. HE, HC, WP, Smoke, and Illum 17. What are the four types of HE fuzes?
a. Delay, VT, Ti, and Quick b. PD, Quick, Ti, and Delay c. Ti, Delay, VT, and PD d. PD, Quick, Ti, and VT
Matching: For items 18 through 22, match the type of artillery shell in column 1 with the description that best identifies its proper usage in column 2. Selections in column 2 may be used more than once. After the corresponding number on the answer sheet, blacken the appropriate circle.
Column 1 Column 2
Shell Description
___ 18. HE a. Can be used to start fires, or for screening
___ 19. WP b. Used for screening and obscuration
___ 20. Smoke c. Is more effective against personnel than
___ 21. ICM other types
___ 22. Illumination d. Is versatile when used with different fuzes e. Is used to observe the battlefield
23. To orient yourself to the target area, you must first ____________, then ___________, and _____________.
a. establish your position, establish direction, locate your targets b. establish direction, establish your location, locate your targets c. establish your location, locate your target, determine direction d. establish direction, locate your targets, establish your position 24. Which of the following is a terrain sketch?
a. A reference tool for determining directions within the target area
b. A technically correct representation of the target area from your viewpoint c. A precise record of targets you have located
d. A sketch of targets and known points you can see 25. What is an OF fan used for?
a. Determining directions to known points on a map b. Determining directions to targets on a map c. Locating targets on a map
27. You measure an azimuth of 1430 to a target using your lensatic compass. The declination diagram shows a GM angle of (magnetic left) 140 mils. What is the target direction?
a. 1290 c. 1570
b. 1430 d. 1750
28. What are the two quickest methods for measuring angles between objects?
a. Leapfrogging or hasty measurement
b. Directional instrument or hand measurement c. Leapfrogging or binocular reticle pattern d. Hasty measurement or binocular reticle pattern
29. In the illustration below, what is the angle between the vertex and the target?
a. 3 mils c. 30 mils
b. 3.5 mils d. 35 mils
30. Using the illustration below, determine the distance to the target. You have
30. Using the illustration below, determine the distance to the target. You have