The AN/KAS-1 is now ready for operation.

To conduct the AN/KAS-1 operator check, turn on the PCU CB1 switch. The sensor unit cooler will operate. After about 3 minutes, the sensor will reach cool down and an IR scene should be visible in the eyepiece. If the IR scene is not visible or clear, use the following steps to troubleshoot the problem:

1. Place the PCU S1 switch in the test position. If all lights come on but there is no IR scene visible in the eyepiece within 5 minutes, replace the sensor unit. If the DS3 fails to light up, the ship's power to the PCU is OFF. Check the ship's power. If the DS3 lights up but there is no image and either the DS1 or the DS2 fails to light up, replace the PCU. If some of the lights are out but the IR scene is visible in the eyepiece, replace the defective lamp.

2. Adjust the BRT (brightness) and the CTRS (contrast) to obtain a good image. Remember this image, because on foggy or hazy days the image will not focus sharply. If you are in a lowvisibility or heavy fog condition, use the narrow field of view and focus on a hot object within 50 feet of the sensor. If you are unable to obtain a good image, replace the sensor unit.

3. Using the narrow field of view, observe the hot object at 50 feet or more and image. Switch to the wide field of view and verify the focus. Always focus the AN/KAS-1 in the narrow field of view; this will focus the wide field of view also. If you are unable to focus the image, replace the sensor unit.

When you are identifying clouds (fig. 9-13), use the following procedures:

1. Use only the wide field of view so that the entire cloud can be seen.

Figure 9-13.-Interrogating with the chemical warfare directional detector (CWDD).

2. Aim the sensor unit at the cloud and begin your interrogating (moving through the filters) immediately by depressing the filter switch.

3. Go through the interrogation several times, watching the changes as the cloud forms. If the cloud is a chemical nerve agent cloud, the changes will become even more apparent as you watch it through the filters.

4. Continue the interrogation for at least six cycles until confirmation can be established.

5. If the cloud dims and grows smaller when using filter No. 1 and grows larger when using the No. 2 and No. 3 filters, take immediate action to notify the bridge. Even if the suspected cloud is not a chemical agent, keep interrogating other suspicious looking clouds.

When conducting maintenance on the AN/KAS-1, follow the procedures listed in the manufacturer's technical manual and the PMS system.