PROCESO DE DECISIÓN DE COMPRA 1 Descripción del proceso de compra

PURPOSE

The M1A2 ballistic solution check verifies that the FCS is correctly implementing ballistic solutions in all main gun channels.

Note. The M1A2 Special Input Check and M1A2 Ballistic Solution Check do not test components of the FCS; they test the ability of the TEU to compensate for values received from these components and determine a ballistic solution for a given round.

CONDITIONS

1. The ballistic solution board is shown in Chapter 3, Figure 3-1, pages 3-8 and 3-9.

2. The engine is off; the VEHICLE MASTER POWER, TURRET POWER, and AUX HYDR POWER are on; and the FIRE CONTROL MODE switch is in the NORMAL position.

Note. The M1A2 Special Input Check and M1A2 Ballistic Solution Check must be performed with the AUX HYDR POWER on. Performing these checks at zero pressure does not test the FCS's ability to apply offsets to the gun correctly.

PROCEDURE

WARNING

Range solutions must be entered manually with the GCDP data key during the M1A2 Special Input Check and M1A2 Ballistic Solution Check. Do not use the LRF; it may expose unprotected personnel to injury.

Note. If the tank passed the M1A2 Special Input Check and the current boresight is still valid, start at step 8.

If maintenance was performed on the system or the boresight has changed, start at step 1.

1. Grip one of the palm switches; then (with the palm switch pressed) press the SENSOR push button on the main menu. Press the RANGE push button on the SENSOR menu, index 1,200 meters into the GCDP, and press the ENT push button on the keypad. Hold the palm switch for five seconds, then release. (When conducting the special input check, the range value must be entered with the palm switch pressed. Failure to enter the range with the palm switch pressed will result in a failure of the M1A2 Ballistic Solution Check.)

2. Put the FCS in the BORESIGHT mode by pressing the ADJUST push button on the main menu, then pressing the BORESIGHT push button on the ADJUST menu.

3. Press the GPS push button.

Note. Do not rotate the MBD while performing the M1A2 Special Input Check and M1A2 Ballistic Solution Check.

4. Insert the MBD and direct the gunner to lay the main gun manually on the center of the target marked gun on the solution board, with last movement up.

Note. When using the M27A1 at this distance, use the GPS eyepiece parallax shield and the MBD's eyesight parallax shield (optic cover with hole) to reduce eyesight parallax.

5. When the main gun is properly laid for direction, the gunner looks through the GPS eyepiece and, using the four-way switch on the GCDP, moves the reticle to the center of solution board target marked GPS.

6. Store the boresight data by pressing the ENT push button on the GCDP keypad.

Note. The gunner may refer the GAS boresight cross to the gun box as a reference for gun position, as well as the MBD.

7. Check boresight solution.

Note. If the tank failed the M1A2 Special Input Check and maintenance was performed, make sure the zero data (CCF) for each type AMMO SUBDES is set at 0.00 and 0.00, and the MRS update and boresight numbers are set at 0.00 and 0.00 before conducting the M1A2 Ballistic Solution Check. Failure to do so will result in a failure of the M1A2 Ballistic Solution Check.

8. Check the 13 separate main gun solutions.

a. Manually index the data inputs (except for range) into the GCDP for a given solution as provided in Table 5-2.

b. Grip one of the palm switches; then (with the palm switch pressed) press the SENSOR push button on the MAIN menu. Press the RANGE push button on the SENSOR menu, index 1,200 meters into the GCDP, and press the ENT push button on the keypad. Hold the palm switch for five seconds, then release. (The range value must be entered with the palm switch pressed. Failure to enter the range with the palm switch pressed will result in a failure of the M1A2 Ballistic Solution Check.)

c. Using a G pattern and manual controls, lay the GPS aiming dot back on the aiming point, with last movement up.

d. The crewman on the outside views through the MBD and confirms that the gun is on the correct block.

9. Record the position of the MBD aiming point (in relation to the target block) on the Sample M1A2 Data Worksheet for the M1A2 Special Input Check and M1A2 Ballistic Solution Check on page 5-8.

Notes. Evaluate each column individually. The crewman by the MBD should make sure the aiming dot is on the appropriate block; if it is not, he should note that the MBD was not on the appropriate block.

Possible problems are

• Incorrect boresight.

• Not taking the same sight picture with the MBD that was taken during boresighting.

• GCDP not zeroed (for example, CCF).

• Incorrect entry of checks data into the GCDP.

• Problems with the FCS.

Repeat steps 8a-d for each AMMO SUBDES to be checked.

The solution is correctly implemented if the MBD reticle is within the solution square identified in Table 5-2.

If a solution fails, the crew should rerun the check a second time, paying close attention to make sure the correct procedures are used and the correct data is put into the computer. (If a second try produces the same results, record the results on DA Form 2404 or ULLS Form 5988E, continue the check, and notify organizational maintenance.)

Be sure to reenter previously recorded data for zero (CCF), MRS boresight, and MRS update back into the GCDP upon completion of this check.

Table 5-2. M1A2 Ballistic Computer Inputs for the M1A2 Ballistic Solution Check.