The standard avionics package includes dual audio control panels, dual VHF COMM transceivers, dual NAVs, ADF, and DME, dual transponders, auto flight system, a two-display Rockwell Collins Pro Line 21 Integrated Avionics System and a GPS long range navigational system. Included as part of the auto flight system is altitude preselect, altitude alerting, and altitude reporting. An optional third flight display is available for the Pro Line 21 system. The two COMMs, two NAVs, two transponders, and single ADF receiver are mounted in a stacked arrangement behind the consolidated control panel located in the center instrument panel. Three fans cool the communications rack; fans 1 and 2 (located in the rack) cool the rack and fan 3 (located at floor level) cools the rack in the pedestal. The FAN 1 and FAN 2 annunciators, located at the top right of the panel, will illuminate to warn of a malfunction of the cooling fans. The FAN 1 annunciator monitors the top two fans and will illuminate if one or both of those fans fail. The FAN 2 annunciator will illuminate if the lower cooling fan fails. VHF COMM TRANSCEIVERS Dual KY 196A transceivers and controls are mounted at the top of the consolidated control panel located on the center instrument panel. Each radio is a very high frequency (VHF) unit with a frequency range from 118.000 to 136.975 megahertz (MHz) with 25 kHz spacing. The frequency displays are self-dimming seven-segment gas discharge digital readouts. During ground operation, radio transmissions can be blocked by surrounding terrain or structures. This may possibly be overcome by using the other COMM, because of airplane antenna location. The COMM 1 antenna is on the underside of the fuselage and the COMM 2 antenna is on top of the fuselage. When flying through dry precipitation, it is possible for static electricity to build up and cause the VHF COMMs to automatically squelch to a point where reception range is greatly reduced. Disabling the automatic squelch by pulling out the on/off/volume control (OFF PULUTEST) knob will cause background static in the speaker or headset, but normal reception range will be restored. Pushing the knob back in will restore the automatic squelch. If the headset microphone fails to function properly, check the side console switch in MIC HEADSET, and verify that the hand microphone is fully engaged in its socket. KY-196A Controls The KY-196A control uses two digital readouts to display the controlling (USE) frequency and a pilot selected preset (STBY) frequency. It has four modes of operation; Frequency mode; Channel mode; Channel Programming mode; and direct Tuning mode. The frequency mode of operation allows the pilot to tune a frequency in the standby frequency display and then "flip-flop" the standby and active frequencies by pressing the frequency transfer (double arrow) button. The Channel mode allows up to nine frequencies and the corresponding channel numbers to be recalled from memory. During channel mode of operation, the