Military

APPENDIX D

FIRE DIRECTION CENTER CERTIFICATION

The FDC certification tests the proficiency of soldiers to perform their duties as FDC computers and section sergeants. This appendix provides the commander with a means to verify that their mortarmen are trained in FDC procedures. STRAC specifies that FDC personnel pass an FDC examination semiannually.

Section I. CONDUCT OF THE PROGRAM

The FDC certification program (FDCCP) consists of a written test and a hands-on component. Either component may be changed to conform to a particular mortar organization.

D-1. ELIGIBLE PERSONNEL

Soldiers should meet the following criteria to be evaluated for certification:

  • FDC radiotelephone operation.
  • Fire direction center computer.
  • Section sergeant.

D-2. QUALIFICATION

The FDCCP is designed to be a battalion-sponsored program that the battalion commander can use to certify FDC personnel. The goal is to certify all leaders under a standardized evaluation program.

a. Soldiers must receive a minimum score of 90 percent on the written and 70 percent on the hands-on component (to include a passing score on the mortar gunner's examination).

b. Soldiers may retest only once on any part of the test that they have failed. Soldiers who fail the retest will not be certified and will be required to repeat the FDCCP during the next evaluation. Those who fail a second time should be considered for administrative action.

D-3. GENERAL RULES

The FDCCP should be conducted at regiment/brigade level. Battalions should provide scorers (staff sergeants and above) who are IMLC/11C ANCOC graduates. Considerable training value can be obtained by using a centralized evaluation and by obtaining the experience of several units NCOs. Conditions should be the same for all candidates during the certification. The examining board ensures that information obtained by a candidate during testing is not passed to another candidate.

Section II. M16/M19 PLOTTING BOARD CERTIFICATION

This section tests the candidate's ability to perform FDC tasks using the M16/M19 plotting boards. The candidate analyzes the situation, then selects the appropriate answer. A Fort Benning Installation Map 1:50,000, Edition 1-DMA, Series: V745Z is required for the certification test.

D-4. SUBJECTS AND CREDITS

The certification consists of, but is not limited to, the following tasks:

  • Prepare a plotting board for operation as an observed chart (pivot point).
  • Prepare a plotting board for operation as an observed chart (below pivot point).
  • Prepare a plotting board for operation as a modified-observed chart.
  • Prepare a plotting board for operation as a surveyed chart.
  • Process subsequent FO corrections on all charts.
  • Determine data for sheaf adjustments.
  • Determine data for registration, reregistration, and application of the corrections.
  • Record information on DA Form 2399 (Computer's Record).
  • Record MET data using MET data sheet.
  • Determine and apply MET corrections.
  • Locate and compute data for a grid mission.
  • Locate and compute data for a shift from a known point mission.
  • Locate and compute data for a polar mission.
  • Compute data for open, converged, and special sheaves.
  • Compute data for traversing fire.
  • Compute data for searching fire (60-mm, 81-mm, and 120-mm mortars).
  • Compute data for battlefield illumination.
  • Compute data for a coordinated illumination/HE mission.
  • Determine angle T.
  • Prepare an FDC order (section sergeant).
  • Compute data for a zone mission (4.2-inch mortar only).
  • Locate an unknown point on a map or plotting board using intersection.
  • Locate an unknown point on a map or plotting board using resection.

Section III. MORTAR BALLISTIC COMPUTER CERTIFICATION

This section tests the candidate's ability to perform FDC tasks using the MBC.

D-5. SUBJECTS AND CREDITS

The certification consists of, but is not limited to, the following tasks:

  • Prepare an MBC for operation (minimum initialization).
  • Process subsequent FO corrections.
  • Determine data for sheaf adjustments.
  • Determine data for registration and reregistration.
  • Record information on DA Form 2399 (Computer's Record).
  • Record MET data using MET data sheet.
  • Determine MET corrections.
  • Compute data for a grid mission.
  • Compute data for a shift from a known point mission.
  • Compute data for a polar mission.
  • Compute data for open, converged, and special sheaves.
  • Compute data for traversing fire.
  • Compute data for searching fire (60-mm, 81-mm, and 120-mm mortars).
  • Compute data for battlefield illumination.
  • Compute data for a coordinated illumination/HE mission.
  • Determine angle T.
  • Prepare an FDC order (section sergeant).
  • Compute data for a zone mission (4.2-inch mortar only).
  • Locate an unknown point using intersection.
  • Locate an unknown point using resection.

Section IV. MORTAR BALLISTIC COMPUTER TEST

The following are various situations the candidate analyzes and then selects the appropriate answer.

SITUATION A
The following tasks place the MBC in operation.

TASK:Place the MBC into operation using internal or external power sources.
CONDITIONS:Given a BA 5588/U battery, power supply cable, MBC, and a variable power supply.
STANDARDS:Place the MBC into operation.
 
TASK:Operate the panel switches on the MBC.
CONDITIONS:Given an MBC.
STANDARDS:Operate the panel switches without error.
 
TASK:Perform the MBC system self-test.
CONDITIONS:Given an operating MBC.
STANDARDS:Perform the self-test without error and report any deficiencies, shortcomings, or failures to your supervisor.
 
TASK:Prepare an MBC with initialization data.
CONDITIONS:Given an MBC with setup, weapon, and ammunition data.
STANDARDS:Enter the setup, weapon, and ammunition data into the MBC without error.
SETUP WEAPON DATA
  TIME OUT: 30
TGT PREFIX: AB
TN: 0400-0800
ALARM: OFF
MIN E: 010
MIN N: 060
GD: E01
LAT: +31
LISTEN ONLY: OFF
BIT RATE: 1200
KEYTONE: 1.4
BLK: SNG
OWN ID: A
  UNIT: A Co 2/41 IN
    81-mm (M252)
CARRIER MOUNTED: NO
BP: A2 GRID PA 15880 88950
ALT 0410
AZ: 6400 DEF: 2800
A1: Dir 1600 Dis 035
A3: Dir 4800 Dis 035
A4: Dir 4800 Dis 070
AMMO DATA
  TEMP: 70 deg
HE: M374A2
WP: M375A2
ILL: M301A3
TASK:Compute data for a grid mission.
CONDITIONS:Given an initialized MBC, call for fire using grid coordinates as the method of target location, computer's record, FDC order, and data sheet.
STANDARDS:Compute data for the mission's initial fire command to within 1 mil for deflection and elevation.
 
TASK:Record information on firing records.
CONDITIONS:Given a computer's record and data sheet, call for fire, FO's corrections, information to complete the FDC order, ammunition count, mortar platoon/ section SOP, and MBC.

Figure D-1. Situation A.

1. What is the initial range?

(a) 3018
(b) 2970
(c) 3087
(d) 3047

2. What is the correct initial fire command?

(a) (b)
(c) (d)
NOTE:The first round is fired, and the FO sends: RIGHT 100, DROP 100.
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:That round is fired, and the FO sends: DROP 50, FFE.

3. What is the correct subsequent fire command for the FFE?

(a)

(b)

(c)

(d)

NOTE:The FO sends: END OF MISSION (EOM), 4 TRUCKS DESTROYED, EST 6 CAS. The computer records: EOMRAT AB0400, KNPT 00

SITUATION B
A fire mission is conducted using the call for fire and FDC order in Figure D-2.

Figure D-2. Call for fire and FDC order.

TASK:Compute data for a shift mission.
CONDITIONS:Continued from Situation A.
STANDARDS:Compute data for the mission to within 1 mil for deflection and elevation.

4. What is the correct initial fire command?

(a) (b)
(c) (d)
NOTE:The FO sends: EOM, EST 30 PERCENT CAS. The computer records: EOMRAT AB 0401, KNPT 01.

SITUATION C
The FO calls in a polar mission. His location must be determined before the polar mission may be computed.

TASK:Determine an unknown location by using resection (SURV key).
CONDITIONS:Continued from Situation B.
STANDARDS:Determine the unknown location as a grid coordinate to within 1 meter and record it as an FO location.
NOTE:The FO's call sign is T43. T43 sees KNPT 00 at a direction of 5850 and KNPT 01 at a direction of 5590.
TASK:Compute firing data for a polar mission.
CONDITIONS:Continued from above and using the call for fire and FDC order in Figure D-3.
STANDARDS:Compute the firing data for the mission to within 1 mil for deflection and elevation.

Figure D-3. Situation C.

NOTE:The initial round is fired, and the FO sends LEFT 100.
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:The round is fired and the FO sends: LEFT 50, ADD 50, FFE.
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.

5. What is the correct subsequent fire command for the fire for effect?

(a)

(b)

(c)

(d)

NOTE:The FO calls back: EOM, POL POINT BURNING. The computer records: EOMRAT ABO402, KNPT 02.

6. What is the FO's grid location?

(a) 16743 89354
(b) 16843 89254
(c) 16943 89154
(d) 16154 89943

NOTE:Clear the computer before starting Situation D.

SITUATION D
Your platoon has moved to a firing range.

SETUP WEAPON DATA
  TIME OUT: 30
TGT PREFIX: AA
TN: 0200-0600
ALARM: OFF
MIN E: 003
MIN N: 089
GD: E01
LAT: +31
LISTEN ONLY: OFF
BIT RATE: 1200
KEYTONE: 1.4
BLK: SNG
OWN ID: A
  UNIT: A Co 2/41 IN
    81-mm (M252)
CARRIER MOUNTED: NO
BP: A2 GRID AP 07550 93650
ALT 0460
AZ: 1600 DEF: 2800
A1: Dir 3200 Dis 035
A3: Dir 6400 Dis 035
A4: Dir 6400 Dis 070
AMMO DATA
  TEMP: 70 deg
HE: M374A2
WP: M375A2
ILL: M301A3
FO LOCATION
  W13 AP: 08250 92550
ALT: 0500
TASK:Prepare an MBC with initialization data.
CONDITIONS:Given an MBC with setup, weapon, ammunition, and FO location data.
STANDARDS:Enter the setup, weapon, and ammunition data into the MBC without error.
 
TASK:Store safety data in the MBC.
CONDITIONS:Continuation of situation D and safety diagram data.
STANDARDS:Store the safety diagram data without error.

LLAZ: 1200
RLAZ: 2000
MAX RN: 4000
MIN RN: 0350
MIN CHG: 1
MAX CHG: 8

TASK:Store MET data (Figure D-4) and update to the current file in the MBC.
CONDITIONS:Given an initialized MBC and a completed DA Form 3677.
STANDARDS:Enter MET data in the MBC without error.

Figure D-4. Situation D--first mission.

TASK:Conduct a registration using the MBC.
CONDITIONS:Given an initialized MBC, coordinated registration point, computer's record, data sheet, call for fire, and FDC order in Figure D-5.
STANDARDS:Register the section and determine the firing corrections to within 1 mil for deflection and elevation, and to within 1 meter for range.

Figure D-5. Situation D--second task.

7. What is the correct initial fire command?

(a) (b)
(c) (d)

8 What is the angle T?

(a) 0450 mils
(b) 0500 mils
(c) 0400 mils
(d) 0300 mils

NOTE:The FO sends: LEFT 100, ADD 150.

9. What is the correct elevation?

(a) 1069 mils
(b) 1042 mils
(c) 0961 mils
(d) 1061 mils

NOTE:1. The FO sends: RIGHT 50, ADD 50.
2. That round is fired, and the FO sends: DROP 25, EOM, REGISTRATION COMPLETE

10. What is the RCF?

(a) +44
(b) -51
(c) +51
(d) -44

11. What is the DEFK?

(a) R33
(b) R36
(c) L36
(d) L33

TASK:Compute data for sheaf adjustment.
CONDITIONS:Given an initialized MBC, completed registration mission, computer's record, and corrections from the FO for the adjustment of the remainder of the section.
STANDARDS:Adjust the sheaf and determine the sheaf data to within 1 mil for deflection and elevation.
NOTE:The FDC sends an MTO, "Prepare to adjust sheaf," and the FO replies, "Section right.

12. What is the correct subsequent command?

(a)

(b)

(c)

(d)

NOTE:The FO calls back: NUMBER 1 GUN RIGHT 60; NUMBER 3 GUN LEFT 20; NUMBER 4 ADJUSTED.

13. What are the correct subsequent commands?

(a)
(b)
(c)
(d)
NOTE:The FO spots the last round and sends: EOM, SHEAF ADJUSTED. The computer records as: EOMRAT AA0200, KNPT 00.

SITUATION E
While the section is referring and realigning their aiming posts, the section leader hands you a call for fire.

TASK:Compute data for a shift mission.
CONDITIONS:Continue from Situation D using the call for fire in Figure D-6.
STANDARDS:Compute data for the mission to within 1 mil for deflection and elevation.
 
TASK:Record all information on firing records.
CONDITIONS:Given a computer's record and data sheet, call for fire, FO's corrections, information to complete the FDC order, ammunition count, mortar platoon/section SOP, and MBC.
STANDARDS:Record and compute the mission. Correctly complete all required blocks and spaces on the computer's record. Record the information and data needed for the type of mortar and ammunition being fired at the end. Complete the data sheet.

Figure D-6. Situation E.

14. What is the correct initial fire command?

(a) (b)
(c) (d)
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:The FO spots the first round and sends: ADD 100. That round is fired, and the FO sends: RIGHT 50, ADD 50, FFE.
TASK:Compute data for a converged sheaf.
CONDITIONS:Given an initialized MBC using a grid coordinate as the method of target location, computer's record, and data sheet.
STANDARDS:Compute the firing data for the initial and subsequent fire commands to within 1 mil for deflection and elevation.

15. What is the correct subsequent fire command for the FFE?

(a)
(b)
(c)
(d)
NOTE:The FO sends: EOM. BUNKER DESTROYED, EST 50 PERCENT CAS EOMRAT AA0201, KNPT 01

SITUATION F
The FO calls in a new mission.

TASK:Compute data for a grid mission using the call for fire and FDC order in Figure D-7.
CONDITIONS:Given an initialized MBC, call for fire using grid coordinates as the method of target location, computer's record, and data sheet.
STANDARDS:Compute data for the mission's initial fire command to within 1 mil for deflection and elevation.

Figure D-7. Situation F.

NOTE:The initial round is fired, and the FO sends: RIGHT 100, ADD 100

16. What is the correct subsequent command?

(a)

(b)

(c)

(d)

NOTE:The FO spots the round and sends: ADD 50, FFE.
TASK:Compute data for a traversing mission using the call for fire and FDC order in Figure D-7.
CONDITIONS:Given an MBC with a mission already in progress.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation, and determine turns to the nearest one-half turn.

17. What is the correct subsequent command for the FFE?

(a)
(b)
(c)
(d)
NOTE:The FO sends: EOM, BRIDGE DESTROYED, EOMRAT AA0202, KNPT 02.

SITUATION G
W13 sends in the fire request in Figure D-8.

TASK:Record information on firing records.
CONDITIONS:Given a computer's record and data sheet, call for fire, FO's corrections, information to complete the FDC order, ammunition count, mortar platoon/ section SOP, and MBC.
STANDARDS:Record and compute the mission. Correctly complete all required blocks and spaces on the computer's record. Record the information and data needed for the type of mortar and ammunition being fired at the end. Complete the data sheet.

Figure D-8. Situation G--first mission.

W13 immediately sends in another fire request. The section leader assigns No. 1 and No. 2 guns to the first mission (SHIFT), and No. 3 and No. 4 guns to the second mission (POLAR).

TASK:Compute data for a shift mission using the call for fire and FDC orders in Figure D-8.
CONDITIONS:Given an initialized MBC, call for fire using shift from a known point, computer's record, and data sheet.
STANDARDS:Compute data for the mission to within 1 mil for deflection and elevation.
 
TASK:Compute firing data for a polar mission using the call for fire and FDC orders in Figure D-9.
CONDITIONS:Given an initialized MBC, call for fire, computer's record, and data sheet.
STANDARDS:Compute the firing data for the mission to within 1 mil for deflection and elevation.
 
TASK:Compute firing data for a polar mission using the call for fire and FDC orders in Figure D-9.
CONDITIONS:Given an initialized MBC, call for fire, computer's record and data sheet.
STANDARDS:Compute the firing data for the mission to within 1 mil for deflection and elevation.

Figure D-9. Situation G--second mission.

18. What is the correct range for the first round in mission one?

(a) 2,408 meters
(b) 3,628 meters
(c) 3,354 meters
(d) 2,508 meters

19. What is the correct initial fire command for mission two?

(a) (b)
(c) (d)
NOTE:The first mission's initial round is fired, and the FO sends: RIGHT 50, DROP 100.
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.

20. What is the correct subsequent command for mission one?

(a)

(b)

(c)

(d)

NOTE:The FO spots the round for mission two and sends: DROP 50, FFE.

21. What is the correct subsequent command for the second mission?

(a)

(b)

(c)

(d)

NOTES:

1. The FO spots the second round for the first mission and sends: ADD 50, FFE.

2. The FO calls back on the second mission: EOM, BMP DESTROYED, EOMRAT AA204, KNPT 04.

22. What is the correct subsequent command for the first FFE mission?

(a)

(b)

(c)

(d)

NOTE:The FO sends: EOM, EST 80 PERCENT CAS, EOMRAT AA0203, KNPT 03.

SITUATION H
The company commander orders the mortar platoon to displace. The platoon occupies the new position. The initialization data below is entered into the MBC.

TASK:Prepare an MBC with initialization data.
CONDITIONS:Given an MBC with weapon and FO location data.
STANDARDS:Enter the weapon and FO location data into the MBC without error.
WPN DATA
 81-MM (M252)
CARRIER MOUNTED: NO
BP: A2 GRID: AP: 13225 92885
ALT: 0420
AZ: 5340 DEF: 2800
A1: Dir 0540 Dis 035
A3: Dir 3740 Dis 035
A4: Dir 3740 Dis 070
FO LOCATION
 F21 AP: 09850 93100
ALT: 0300
TASK:Store a no-fire line/zone in the MBC.
CONDITIONS:Given an initialized MBC and coordinates for a no-fire line/zone.
STANDARDS:Store a no-fire line/zone without error.
NO FIRE LOCATION
 ZN1 04 PTS
PT1 09450 93300
PT2 10650 93300
PT3 10650 93500
PT4 09450 93500
TASK:Store safety data in the MBC.
CONDITIONS:Given an initialized MBC and a completed safety diagram.
STANDARDS:Store the safety diagram data without error.
SAFETY DATA
 LLAZ 4940
RLAZ 5740
MAX RN 3800
MIN RN 0450
MIN CHG 1
MAX CHG 7

The company commander has directed that an FPF be placed at grid 10850 93410. The platoon leader informs the FO, and the FO sends the call for fire in Figure D-10.

Figure D-10. Situation H.

TASK:Compute firing data for an FPF.
CONDITIONS:Given an initialized MBC, a call for fire (requesting adjustment of an FPF), computer's record, and data sheet.
STANDARDS:Compute data for an FPF to the nearest 1 mil for deflection and elevation.
NOTE:No. 4 gun is the danger-close gun.

23. What is the burst point grid for the first round?

(a) 10850 93410
(b) 10788 93304
(c) 10920 93411
(d) 10790 93000

24. What are the correct initial deflections and elevations?

 DEF (mils)ELEV (mils)
(a)No. 1
No. 2
No. 3
No. 4
3128
3127
3126
3200
1045
1045
1046
0900
(b)No. 1
No. 2
No. 3
No. 4
3180
3179
3178
3124
0995
0995
0994
0900
(c)No. 1
No. 2
No. 3
No. 4
3040
3039
3038
3200
0945
0994
0946
0900
(d)No. 1
No. 2
No. 3
No. 4
3141
3141
3141
3141
0969
0969
0969
0969
NOTE:The FO spots the round and sends: NO. 4 GUN, LEFT 25, ADD 25.
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:The round is fired and the FO sends: NO. 4 GUN ADJUSTED, REPEAT NO. 3 GUN.

25. What is the correct deflection and elevation for No. 3 gun?

 DEF (mils)ELEV (mils)
(a)
(b)
(c)
(d)
3134
3124
3126
3134
1059
1050
3127
0975
NOTE:

1. The FO spots the round and sends: RIGHT 25.

2. That round is fired, and the FO sends: NO. 3 ADJUSTED, REPEAT NO. 2 GUN

3. The round is fired, and the FO sends: RIGHT 25, ADD 25.

26. What is the correct deflection and elevation for the No. 2 gun?

 DEF (mils)ELEV (mils)
(a)
(b)
(c)
(d)
3126
3141
3127
3141
0974
0977
0975
0950
NOTE:

1. The round is fired, and the FO sends: NO. 2 ADJUSTED, REPEAT NO. 1 GUN.

2. The round is fired, and the FO sends: EOM, FPF ADJUSTED.

SITUATION I
A short time after adjusting the FPF, you receive the call for fire and FDC order in Figure D-11.

TASK:Compute data for a grid mission using the call for fire and FDC order in Figure D-11.
CONDITIONS:Given an initialized MBC, call for fire using grid coordinates as the method of target location, computer's record, and data sheet.
STANDARDS:Compute data for the missions initial fire command to within 1 mil for deflection and elevation.

Figure D-11. Situation I.

27. What is the correct initial fire command?

(a) (b)
(c) (d)
NOTE:The FO sends: EOM, AREA SCREENED, EOMRAT AA0205, KNPT 05.

SITUATION J
The commander wants a screen at grid 11850 94150. The platoon leader informed the FSO and the FO. A short time later you receive the call for fire in Figure D-12.

TASK:Compute firing data for a quick-smoke mission.
CONDITIONS:Given an initialized MBC, call fire fire (requesting a quick smoke mission), weather conditions, smoke card, computer's record, and data sheet.
STANDARDS:Compute the initial and subsequent fire commands to the nearest 1 mil for deflection and elevation, and the correct number of rounds in the FFE.

Figure D-12. Situation J.

NOTE:Temperature gradient--neutral; wind speed--9 knots; humidity--60 percent

28. What is the deflection for the last round fired?

(a) 2468
(b) 2498
(c) 2388
(d) 2598

NOTE:

1. The FO spots the round and sends: LEFT 50, ADD 100.

2. The round is fired and the FO sends: ADD 100.

3. The FO spots the round and sends: REPEAT WP.

4. The FO sees the WP and sends: FFE, CONTINUOUS FIRE FROM THE LEFT.

29. What is the time interval between rounds?

(a) 20 seconds
(b) 10 seconds
(c) 12 seconds
(d) 6 seconds

30. What is the total number of WP rounds computed for the mission?

(a) 37 rounds
(b) 40 rounds
(c) 41 rounds
(d) 28 rounds

NOTE:The FO calls back: EOM, AREA SCREENED, EOMRAT AA0206, KNPT 06.

SITUATION K
The platoon leader has been ordered to displace No. 3 and No. 4 guns to a new firing point. Enter the following weapon data:

TASK:Prepare an MBC with initialization data.
CONDITIONS:Given an MBC with weapon data.
STANDARDS:Enter the weapon data into the MBC without error.
WPN DATA
 BP: B3
CARRIER MOUNTED: NO
GRID: 10750 91300
ALT: 0350
AZ: 6400 DEF: 2800
B4: Dir 4900 Dis 040

Shortly after the section occupies its new position, another fire request is received. Use the call for fire and FDC order in Figure D-13 to compute the mission.

TASK:Compute firing data for a polar mission using the call for fire and FDC orders in Figure D-13.
CONDITIONS:Given an initialized MBC, call for fire, computer's record, and data sheet.
STANDARDS:Compute the firing data for the mission to within 1 mil for deflection and elevation.

Figure D-13. Situation K.

31. What is the correct initial fire command?

(a) (b)
(c) (d)
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:The FO sends the correction: ADD 50, FFE.

32. What is the correct subsequent command?

(a)
(b)
(c)
(d)
NOTE:The FO sends: EOM, TANKS BURNING, EOMRAT AA0207, KNPT 07.

SITUATION L
The No. 3 and No. 4 guns have now displaced back to their position with the rest of the platoon. Another mission is received in the FDC. Use the call for fire and FDC order in Figure D-14 to compute the mission.

TASK:Compute data for a searching mission using the call for fire and FDC order in Figure D-14.
CONDITIONS:Given an MBC with a mission already in progress.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation, and determine turns to the nearest one-half turn.

Figure D-14. Situation L.

TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTES:

1. The FO spots the initial round and sends a correction: RIGHT 200, DROP 200.

2. That round is fired, and the FO sends his next correction: LEFT 50, DROP 100.

3. That round is fired, and the observer calls back: ADD 50, FFE.

33. What is the correct deflection, charge, and elevation for the near edge of the target?

 DEF (mils)CHGELEV (mils)
(a)
(b)
(c)
(d)
2652
2642
2645
2642
6
7
7
7
1062
1083
1072
1072

34. What is the correct deflection, charge, and elevation to the far edge of the target?

 DEF (mils)CHGELEV (mils)
(a)
(b)
(c)
(d)
2649
2649
2645
2649
6
7
7
7
0982
0997
1051
0982
NOTE:The FO observes the FFE and sends: EOM, TROOPS DISPENSING, EOMRAT AA0208, KNPT 08.

SITUATION M
Just at dusk of the same day, the FDC receives another fire request. Use the call for fire and FDC order in Figure D-15 to compute the mission.

TASK:Compute data for a traversing mission using the call for fire and FDC order in Figure D-15.
CONDITIONS:Given an MBC with a mission already in progress.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation, and determine turns to the nearest one-half turn.

Figure D-15. Situation M.

TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTES:

1. The FO spots the round and sends the correction: LEFT 200, DROP 200.

2. The round is fired, and the FO sends another correction: RIGHT 100, ADD 25.

3. The round is spotted by the FO, and he sends the correction: LEFT 50, FFE, TRAVERSE RIGHT.

35. What is the subsequent command for the FFE?

(a)
(b)
(c)
(d)

36. How many turns are there between rounds?

(a) 1/2 turn
(b) 1 turn
(c) 1 1/2 turns
(d) 2 turns

NOTE:The FO observes the FFE and sends: EOM LZ DESTY.

SITUATION N
It is now dark and the platoon is prepared for night firing. The FDC receives a fire request. Use the call for fire and FDC order in Figure D-16 to compute the mission.

TASK:Compute firing data for an illumination mission.
CONDITIONS:Given an initialized MBC, call for fire, computer's record, and data sheet.
STANDARDS:Compute data for an illumination mission to the nearest 1 mil for deflection and elevation, and time setting to within one-tenth of a second.

Figure D-16. Situation N.

TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTE:The round is fired and the FO sends the correction: RIGHT 200, DROP 400, DOWN 100.

37. What is the correct subsequent command?

(a)

(b)

(c)

(d)

TASK:Compute data for a coordinated illumination mission using the call for fire in Figure D-17.
CONDITIONS:Given an initialized MBC, call for fire, computer's record, and data sheet.
STANDARDS:Compute firing data for the deflection and elevation to within 1 mil for all high-explosive and illumination rounds for the initial and subsequent fire commands.
NOTE:The round is fired, and the FO sends a coordinated illumination and HE call for fire.

Figure D-17. Situation N--second mission.

38. What is the correct FDC order?

(a) (b)
(c) (d)
TASK:Compute data for subsequent FO corrections using the MBC.
CONDITIONS:Given an MBC with a mission already in progress and corrections from the FO to apply.
STANDARDS:Compute data for the corrections to within 1 mil for deflection and elevation.
NOTES:

1. No. 1 gun fires an illumination round and the FO sends: ILLUM MARK.

2. The MARK TIME is 50 seconds.

3. ILL and HE rounds are fired and the FO calls back: HE, DROP 100.

39. What is the range to the target for this correction?

(a) 2,358 meters
(b) 2,318 meters
(c) 2,198 meters
(d) 2,258 meters

NOTE:ILL and HE rounds are fired, and the FO calls back: HE, RIGHT 50, DROP 50, FFE

40. What is the correct deflection and elevation for the No. 2, No. 3, and No. 4 guns in the FFE?

 DEF (mils)ELEV (mils)
(a)
(b)
(c)
(d)
2946
2946
2946
2946
1047
1055
1063
1070
NOTE:The FO observes the FFE and sends: EOM, VEHICLES BURNING, EOMRAT AA0409, KNPT 09.

SITUATION O

The following are questions relating to various MBC situations:

41. When the MBC is connected to a radio, it is proper procedure to conduct a MODEM test.

TRUEFALSE

42. While operating the MBC, the computer becomes unusually hot and a hissing sound is detected. The first thing to do is turn the MBC off.

TRUEFALSE

43. When storing the MBC, the battery can be left in the computer for an unlimited length of time.

TRUEFALSE

44. While operating the MBC using an external power source in the vehicle, the vehicle should not be started.

TRUEFALSE

45. Never use a sharp object, such as a pencil, to press the switches when operating the MBC.

TRUEFALSE

46. The MBC is waterproof when one switch on the keyboard is punctured.

TRUEFALSE

47. The first step before operating the MBC is to place a battery into the battery compartment.

TRUEFALSE

48. The last check before operating the MBC is to conduct a self-test.

TRUEFALSE

49. How many types of messages can the MBC receive from a DMD?

a. 4
b. 9
c. 14
d. 2

50. When receiving a completed fire request (FR) message from the DMD, why must you review it before processing the mission?

a. To prevent errors.
b. To be able to send an MTO.
c. To receive an ACK.
d. To manually enter the GRID switch.

51. When entering SET-UP, data what two entries must be the same as the DMD to communicate digitally?

a. Listen Only and Bit Rate.
b. Bit Rate and Block Mode.
c. Key Tone and Black Mode.
d. Bit Rate and Key Tone.

52. After pushing the COMPUTE switch during a mission and the display window displays *RANGE ERR*, what is the correct action to take?

a. End the mission.
b. Clear the MET.
c. Verify initialization and input entries.
d. Enter a higher charge and recompute.

53. When receiving an FR from a DMD or over the radio, the display window displays SAFETY VIOLATION. What corrective action should be taken?

a. Recompute.
b. Send an MTO.
c. Send a CMD message.
d. Clear out safety diagram.

54. Which FM or TM is used when performing a PMCS on the M23 mortar ballistic computer?

a. FM 23-90.
b. TM 9-1350-261-10.
c. TM 9-1300-257-10.
d. TM 9-1220-246-12&P.

55. After entering safety data into the MBC, the need for safety T's is no longer warranted.

TRUEFALSE

Section V. PLOTTING BOARDS

SITUATION A
You are going to the firing range. The platoon leader goes to range control and obtains the safety information. Using the information below, construct a safety diagram.

TASK:Construct a safety diagram on the M16 plotting board.
CONDITIONS:Given an M16 plotting board, right and left limit azimuths, minimum and maximum ranges, type of weapon, firing point with either 8 or 10-digit grid coordinates, charge zones, and 300-series firing table.
STANDARDS:Convert left and right limits to deflections, and minimum and maximum ranges to elevations. Construct a diagram on an M16 plotting board without error.

Mortar grid: 06406580
Left limit azimuth: 4800
Right limit azimuth: 5600
Maximum range: 4,000
Minimum range: 500
Charge zone: 2-8
Referred deflection: 2800

56. What are the left and right deflections?

 LEFT DEF (mils)RIGHT DEF (mils)
(a)
(b)
(c)
(d)
2400
4800
2800
3200
1200
5600
2400
2400

57. What is the minimum elevation (mils that can be fired at the maximum range)?

(a) 0941 mils
(b) 1471 mils
(c) 0907 mils
(d) 1428 mils

SITUATION B
You move out to the field. The platoon leader determines an eight-digit grid and an altitude to the mortar position. He instructs you to construct a modified-observed firing chart.

TASK:Prepare a plotting board for operation using the modified-observed firing chart.
CONDITIONS:Given an M16 plotting board, a Fort Benning Installation Map 1:50,000, Edition 1-DMA, Series:V745Z; a mil protractor; area of responsibility; a direction of fire (DOF); an eight-digit coordinate to the mortar position; target or registration point (RP); and a grid intersection to represent the pivot point.
STANDARDS:Superimpose a grid system on the M16 plotting board using the grid intersection given without error.
 
TASK:Forward plot a target to the modified-observed chart from an observed chart.
CONDITIONS:Given an M16 plotting board, data sheet with previously fired targets, setup data, computer's record, call for fire, and firing table.
STANDARDS:Plot the target, compute the firing data to within 1 mil with a 10-mil tolerance for deflection and 25 meters for range with a 25-meter tolerance, and record and update firing records without error.

Mortar grid: 07506539            Altitude: 440
OP No. 1: 096660                  Altitude: 450
Direction of fire: 2020 mils
Grid intersection: 09/64
Mounting azimuth: 2000 mils
Referred deflection: 4800 mils
Forward plot AC070: Chart deflection: 4536 mils
                                  Chart range: 2,950 meters
                                  Altitude: 440 meters

The section leader receives a call for fire and checks the map. He then hands you the call for fire in Figure D-18 and instructs you to compute the mission.

TASK:Compute data for a grid mission using the call for fire and FDC order in Figure D-18.
CONDITIONS:Given an M16 plotting board, sector of fire, 1:50,000 map, protractor, computer's record, tabular firing tables, call for fire for a grid mission, FO corrections, paper, and pencil.
STANDARDS:Determine the deflection to within 1 mil with a 10-mil tolerance and the range to within 25 meters with a 25-meter tolerance.
 
TASK:Determine the vertical interval (VI) between the mortar altitude and the target altitude.
CONDITIONS:Given the mortar altitude and the target altitude.
STANDARDS:Determine the VI to the nearest whole meter and the range correction to apply without error.
 
TASK:Determine VI to the nearest whole meter and the range correction to apply without error.
CONDITIONS:Given an M16 plotting board, altitude of the mortar position, call for fire with the target altitude, and a firing table.
STANDARDS:Apply the VI correction without error when computing a mission. Record and update firing records. Determine deflections to the nearest 1 mil with a 10-mil tolerance. Determine the range to within 25 meters with a 25-meter tolerance. Convert the range to the correct charge and elevation.
 
TASK:Compute angle T.
CONDITIONS:Given the observer to target (OT) direction, direction of fire (GT), No. 2 pencil, and paper.
STANDARDS:Determine the angle T to the nearest 1 mil. Record the angle T to the nearest 10 mils. Send the angle T to the nearest 100 mils to the FO. Notify the FO in the message to observer (MTO) when the angle T exceeds 500 mils.

Figure D-18. Situation B--first mission.

58. What is the initial chart deflection?

(a) 3205 mils
(b) 5205 mils
(c) 2800 mils
(d) 0700 mils

59. What is the command range to fire the first round?

NOTE:The chart range is 2,300.

(a) 2,300 meters
(b) 2,325 meters
(c) 2,375 meters
(d) 2,275 meters

NOTE:The FO spots the first round and sends these corrections: RIGHT 150, DROP 50, FFE; OT direction 1800.

60. What is the correct subsequent fire command?

(a)

(b)

(c)

(d)

NOTE:The rounds are fired and the FO sends EOM. Update and mark as target AC071.

You receive the call for fire in Figure D-19 and see that it is in your area of operations. You are instructed to compute the mission.

TASK:Compute data for a grid mission using the call for fire and FDC order in Figure D-19.
CONDITIONS:Given an M16 plotting board, sector of fire, 1:50,000 map, protractor, computer's record, tabular firing tables, call for fire for a grid mission, FO corrections, paper, and No. 2 pencil.
STANDARDS:Determine deflection to within 1 mil with a 10-mil tolerance and range to within 25 meters with a 25-meter tolerance.
 
TASK:Determine the vertical interval (VI) between the mortar altitude and the target altitude.
CONDITIONS:Given the mortar altitude and target altitude.
STANDARDS:Determine the VI to the nearest whole meter and the range correction to apply without error.
 
TASK:Determine VI and the correction to apply when computing a mission using the M16 plotting board.
CONDITIONS:Given an M16 plotting board, altitude of the mortar position, call for fire with the target altitude, and firing table.
STANDARDS:Apply the VI correction without error when computing a mission. Record and update firing records. Determine deflections to the nearest 1 mil with a 10-mil tolerance. Determine the range to within 25 meters with a 25-meter tolerance. Convert range to the correct charge and elevation.
 
TASK:Compute angle T.
CONDITIONS:Given the observer-target (OT) direction, direction of fire (GT), No. 2 pencil, and paper.
STANDARDS:Determine the angle T to the nearest 1 mil. Record the angle T to the nearest 10 mils. Send the angle T to the nearest 100 mils to the FO. Notify the FO in the message to observer (MTO) when the angle T is 500 mils or more.

Figure D-19. Situation B--second mission.

61. What is the FDC order?

(a) (b)
(c) (d)

You are handed the call for fire and FDC order in Figure D-20 and are instructed to compute the mission.

TASK:Compute data for a shift mission using a plotting board.
CONDITIONS:Given a plotting board, computer's record, firing table, call for fire for a shift mission, and FO corrections.
STANDARDS:Determine deflection to within 1 mil with a 10-mil tolerance and range to within 25 meters with a 25-meter tolerance.

Figure D-20. Situation B--third mission.

62. What is the initial deflection?

(a) 4606 mils
(b) 4994 mils
(b) 4800 mils
(d) 4660 mils

63. The initial chart range is 2,375. What is the command range?

(a) 2,325 meters
(b) 2,350 meters
(c) 2,375 meters
(d) 2,400 meters

NOTE:The FO spots the first round and sends this correction: ADD 50, FFE.

64. What is the final deflection for the adjusting mortar?

(a) 4999 mils
(b) 4805 mils
(c) 4665 mils
(d) 4611 mils

NOTE:The adjusted chart range is 2,450.

65. What is the deflection for No. 3?

(a) 4627
(b) 4611
(c) 4595
(d) 4665

NOTE:The FO sends EOM. Mark as target AC073.

You receive the call for fire, check the map, and issue the FDC order to the computers. Using the call for fire and FDC order in Figure D-21, compute the mission.

TASK:Compute data for a polar mission using a plotting board.
CONDITIONS:Given an M16 plotting board prepared for operation to include the mortar position, reference points, and FO positions plotted; firing tables; computer's record; call for fire using the polar method of target location; and subsequent corrections.
STANDARDS:Determine deflection to the nearest 1 mil with a 10-mil tolerance, determine range to 25 meters with a 25-meter tolerance, and convert range to the correct charge and elevation.

Figure D-21. Situation B--fourth mission.

66. What is the correct initial fire command?

(a) (b)
(c) (d)
NOTE:The FO spots the first round and sends: DROP 50, FFE.

67. What is the correct subsequent fire command?

(a)

(b)

(c)

(d)

NOTE:The FO sends EOM.

SITUATION C
Your platoon is moving to a defensive position for a few days. Your platoon leader has the site surveyed. He then instructs you to set up a surveyed firing chart and to conduct a coordinated registration. Using the information below, construct a surveyed chart. Using the information in Figure D-22, conduct the registration mission.

TASK:Construct a surveyed firing chart.
CONDITIONS:Given an M16 plotting board, a grid intersection to represent the pivot point, a surveyed mortar position, a surveyed registration point, and a referred deflection.
STANDARDS:Determine the direction of fire to the nearest mil, determine the mounting azimuth to the nearest 50 mils, and superimpose the deflection scale without error.
 
TASK:Compute data for a registration mission using a plotting board.
CONDITIONS:Given an M16 plotting board, surveyed mortar position, and surveyed registration point.
STANDARDS:Determine the deflection to within 1 mil with a 10-mil tolerance. Determine the range to within 25 meters with a 25-meter tolerance. Convert the range to the correct charge and elevation without error.

Mortar grid: 06726544
RP No. 1 grid: 09946362
Referred deflection: 3800 mils
Grid intersection: 08/64
Altitude: 450 meters
Altitude: 400 meters

Figure D-22. Situation C--first mission.

68. What is the direction of fire?

(a) 2270 mils
(b) 2130 mils
(c) 3800 mils
(d) 2170 mils

69. What is the command deflection and command range for the first round?

 DEF (mils)RANGE (mils)
(a)
(b)
(c)
(d)
3373
3820
3820
3773
3,775
3,750
3,675
3,625
NOTE:The FO spots the first round and sends these corrections: LEFT 50, ADD 50.

70. What is the deflection and elevation for the second round?

 DEF (mils)RANGE (mils)
(a)
(b)
(c)
(d)
3831
3801
3959
3781
0880
0839
0896
0862
NOTES:

1. The FO spots the second round and sends: ADD 25, EOM, REGISTRATION COMPLETE.

2. The FDC sends a message to the FO: PREPARE TO ADJUST SHEAF.

3. The FO sends: SECTION LEFT.

TASK:Compute firing data for a sheaf adjustment using the plotting board.
CONDITIONS:Given an M16 plotting board, an active registration mission, FO corrections for sheaf adjustments, computer's record, and firing tables.
STANDARDS:Determine total range correction (TRC) to apply within 25 meters range with a 25-meter tolerance.

71. What is the correct subsequent fire command?

(a)

(b)

(c)

(d)

NOTES:

1. The FO makes a spotting and sends: NO. 3, RIGHT 10; NO. 1, RIGHT 20; NO. 4 ADJUSTED, EOM S/A.

2. The command range to the target is 3,750 meters.

72. What are the deflections for the No. 3 and No. 1 guns?

 No. 3 DEF (mils)No. 1 DEF (mils)
(a)
(b)
(c)
(d)
3777
3843
3793
3827
3780
3840
3797
3824
TASK:Determine firing corrections.
CONDITIONS:Given the altitude of a mortar position and registration point (RP) in meters, chart deflection, chart range, adjusted deflection, adjusted range for the RP, or a completed computer's record for a registration mission.
STANDARDS:Determine corrections to include:
a. Altitude correction to within 1 meter.
b. Range difference to the nearest 25 meters.
c. Range correction factor (RCF) to within 1 meter.
d. Deflection correction to within 1 mil.

73. If the initial chart deflection was 3820 and the final chart deflection was 3830, what is the deflection correction for RP No. 1?

(a) R10
(b) 0
(c) L10
(d) L30

74. The initial chart range was 3,700 and the RP was hit at a command range of 3,750. What is the range correction factor (RCF)?

(a) +50
(b) +20
(c) -50
(d) +75

After updating and computing all the corrections, you receive a call for fire. The section leader hands you the call for fire and FDC order in Figure D-23 and instructs you to compute the mission.

TASK:Compute data for a shift mission using a plotting board.
CONDITIONS:Given a plotting board, computer's record, firing table, call for fire for a shift mission, and FO corrections.
STANDARDS:Determine deflection to within 1 mil with a 10-mil tolerance and range to within 25 meters with a 25-meter tolerance.
 
TASK:Compute firing data from a surveyed firing chart for a total range correction mission using a plotting board.
CONDITIONS:Given an M16 plotting board, an RP with deflection correction and range correction factors, call for fire, computer's record, and firing tables.
STANDARDS:Determine total range correction to apply within 25 meters for range with a 25-meter tolerance.

Figure D-23. Situation C--second mission.

75. What is the total range correction for this mission?

(a) -25
(b) +70
(c) 3500
(d) +45



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