TM 1-1520-238-10 4-43 -90 DEG +20 DEG -45 DEG 120 DEG +30 DEG -60 DEG +90 DEG M01-102 Figure 4-16. TADS/PNVS Equipment Data Table 4-14. PNVS Equipment Data Parameter Function Normal Azimuth Operating Range +90 degrees/ –90 degrees Azimuth Stow Position –118 degrees or greater Elevation Operating Range +20 degrees/ –45 degrees Field of View 30 degrees vertical/ 40 degrees horizontal Maximum Slew Rate 120 degrees per second 4.25.1 PNVS Electrical Power. The PNVS receives 115 vac power from the No. 1 essential ac bus and 28 vdc power from the No. 3 essential dc bus through the PNVS AC and PNVS DC circuit breakers on the pilot overhead circuit breaker panel. The PNVS is continuously moni- tored by FD/LS which will illuminate the PNVS caution light segment for a PNVS malfunction. The on command DD/LS test (test 09-PNVS) will fault isolate to the LRU. 4.25.2 TADS Electronic Unit Failure. In the event of a TADS Electronic Unit (TADS computer) failure, the PNVS will be placed in the direct mode automatically by the fire control system. The PNVS turret will be directly driven by the IHADSS sight electronics unit. PNVS turret motion may be limited to 75 degrees left and 75 degrees right in azimuth; turret motion may be erratic beyond the 75 de- gree azimuth position. The message PNVS...DIRECT will be displayed in the sight status block of the pilot’s high ac- tion display. No corrective action is required by or avail- able to the pilot. 4.25.3 Symbol Generator Failure. In the event of a symbol generator failure, the fire control system will auto- matically command the IHADSS display electronics unit to display PNVS FLIR 2 on the pilot/CPG HDU. The PNVS will continue to function normally; however, the video dis- played to the pilot will not have symbology. VDU video will blank and the recorder will be inoperative. Additionally, the CPG will receive TADS FLIR 2 video on the ORT. No cor- rective action is required by or available to the pilot. WARNING If night or simulated night NOE, reaction to the following malfunctions must be immediate, exit of the NOE environment may be required. 4.25.4 PNVS FLIR or Turret Failure. In the event of a failure of the PNVS FLIR or turret assembly, the pilot must place the NVS switch on the collective switchbox (figs 2-11 and 2-12) in the TADS position. TADS will be slaved to the pilot helmet LOS and moded to WFOV FLIR. Nor- mally, this action will provide useable TADS video to the pilot. However, in some cases, the TADS FLIR video may be scrambled following loss of the PNVS FLIR video. If this should occur, reselect PNVS on the pilot’s collective NVS switch and then select TADS. The out-of-synch vid- eo will be corrected. The slew rates of the TADS turret are noticeably slower than those of the PNVS and some gain and level adjustment may be required to obtain optimum image quality. 4.25.5 IHADSS Failure. In the event of an IHADSS fail- ure, either inability to command the PNVS turret or loss of video on the HDU, the pilot must first exit the NOE envi- ronment. and then set the VDU control switch to PLT (fig 4-2) and the ACQ SEL switch to NVS FXD. This configu- ration will allow the pilot to fly a fixed panel mounted dis- play. Terrain flight capability will be directly dependent on pilot proficiency. 4.26 WEAPONS SYMBOLOGY. The weapons symbology is displayed to the CPG on the video from the selected sight. The symbology is shown in figure 4-17. Refer to table 4-15 for symbol definition.