About 130 km to the destination airport, the aircraft will be making preparation for descent. The clearance is being requested from the air space authority. Then the input on the altimeter is inserted for the next target altitude, say 31,000 ft.
The autotrottle system that control the engine power knows that the descent is required and adjusted itself to idle as indicated on the FMA (flight mode annunciator. The aircraft will target the descent rate of 2,500ft/min and airspeed of 0.84 mach. The aircraft will be brought down in step until 10,000 ft, where the FMS will tell the aircraft to fly at 250knots and set to follow the preset landing profile.
As the aircraft approach the terminal controlled area, the ATC pick up the aircraft on the radar and guide the aircraft for the landing profiles. For this to happen, the aircraft is fitted with transponder and identification code which will talk to the ground radar automatically. The ATC will be able to the altitude and the movement of the aircraft on the screen.
In preparation for the landing the ATC will provide the QNH, or the local barometric pressure at the airfield for the pilot to set the pressure. The aircraft is fitted with at least 2 pressure altimeter and 2 radio altimeter.
As the aircraft descends to 10,000 ft, the seat belt sign is being switched on, the landing lights and logo light are on. By then the aircraft will pick up the ILS (instrument landing system) will will provide the landing slope signal and the directional signals.
Continuous communication with the tower is going on as the aircraft descends to lower altitude. E.g of the communication… “evening singapore director, singapore 311 approaching seven thousand feet” .
Singapore director may say..”singapore 311, descent two thousand feet, clear to land runway 240 right.”.
Efforts are taken to ensure that the miscommunication does not happen. The standard phraseology is used, and the Aviation English is being made mandatory for ATC personnels and the pilots.
