With the SSR transponder selected ON and "ALT" (Mode C) selected, an ATSU requests: "G-ABCD, Verify your level," this is to:
Domanda 6, VFR Communications - ATPL - Airline Transport Pilot license
| Identify the aircraft position. |
| Calibrate the radar equipment. |
| Verify the accuracy of the Mode C level information displayed to the controller. |
| Check your altimeter setting. |
