There are two sensors that each landing gear that play the main role, namely the lock-up sensor and the drop-down sensor, which are used to switch on the transmission position signal when the lock-up and lock-down are completed in the landing at take-off phase.
A bleed air system uses a network of ducts, valves and regulators to conduct medium to high-pressure air, "bled" from the compressor section of the engine(s) and APU, to various locations within the aircraft. There it is utilized for several functions inclusive of pressurisation, air conditioning.
VHF-Transceiver
Used in VHF communication systems for maintaining contact between ground and aircraft.
The pitot-static probes mounted on aircraft sense altitude, airspeed, rate of climb, and other related parameters, which are then transmitted to the indication and sensing system.
