lunedì 20 ottobre 2014

Avionics bending: VHF Comm tuning panel

Three VHF (Very High Frequency) communications systems (referred to as the VHF systems) are installed on the airplane.
The VHF systems supply line-of-sight voice communications with ground stations or other airplanes. The VHF systems operate in either 8.33 kHz or 25 KHz increments from a frequency range of 118.00 MHz to 136.975 MHz.

Each VHF system uses 28-volt dc power. The VHF system circuit breakers are located on the overhead circuit breaker panel, P11.

The left VHF system uses power from the dc standby bus and the right VHF system from the right dc bus.
The center VHF system uses power from the left dc bus.

Each control panel contains two frequency controls and displays, two frequency-in-use lights, and a transfer switch.

Each frequency control has two concentric knobs to change the frequency. The outer knob rotates to change the ones, tens, and hundreds units; the inner knob changes the tenths and hundredths units of frequency.
The transfer (TFR) switch can select either displayed frequency. When set, the selected frequency display shows -ACTIVE-.

Avionics bending: ADF tuning panel

The Automatic Direction Finder (ADF) system is a navigational aid. It provides bearing to selected ground stations and is used as an audio receiver. It processes frequencies from 190 kHz to 1750 kHz. This includes the standard AM broadcast and low frequency non-directional beacons.

The ADF control panel is used to select the operating frequency of the system. The system always operates in the ADF mode. In this mode, the system can use the sense antenna input to receive AM radio or weather broatcasts. By using both sense and loop antenna inputs, the system can also determine bearing to the selected station. This bearing data can be displayed on RDMI or RMI and EHSI (if installed).


sabato 18 ottobre 2014

Avionics bending: Fuel Temperature indicator

The fuel temperature and indicating system measures the fuel temperature and supplies visual indication of the temperature on the overhead panel, P5. The system has a fuel tank sensor and a temperature indicator. Power is supplied to the system by the 28 volt dc left bus. Information displayed is used in conjunction with the fuel de-icing system when it may be advisable to use the fuel heater to prevent fuel icing at the fuel filter.


The sensor and lead resistance form two legs of an input bridge circuit. The resulting signal from the bridge circuit is amplified, converted from analog to digital, and shown as a digital readout.To do a test of the fuel temperature indicator, put the fuel quantity test switch on the P61 panel to FUEL QTY. The readout should show -185+/-2.