Pilots flying round the world and those at home sometimes have problems understanding one another. They think and calculate for example in different units of measure for distances, speeds and times. Here are a few brief explanations of the technical terms.

1. Distance and speed

In Germany, distances and accordingly the speed are expressed in the metric system. Pilots use miles and knots as units of measure. This is how they are converted:

Nautical miles (nm) Kilometres (km)	1 nm = 1.85 km 1 km = 0.54 nm
Foot (ft) Meter (m)	1 ft = 0.31 m 1 m = 32 ft
Knots (kts) Kilometres per hour(km/h)	1 kt = 1.85 km/h 1 km/h = 0.54 kts

2. Flight-Level (FL)

The term flight level refers to a level of the same air pressure, compared with the pressure in normal atmosphere at sea level. Flight level 90 for example corresponds to an altitude of 9,000 feet or 2,790 m with an air pressure of 1,013.25 hectopascals (hPa) at sea level.

3. Time zones

3.1. Universal Time Coordinated (UTC)

Regardless of their position and the time zone they are in, pilots use the coordinated global time Universal Time Coordinated, or UTC. It refers to Greenwich Mean Time; Greenwich in London is located on the zero meridian. By using UTC, there are no international misunderstandings as regards the time, for example for takeoff or landing times.

The 24 time zones are stated as positive (easterly) or negative (westerly) differences from UTC. Used as a reference point, the local time can then be calculated. UTC + 1 is example of the mid-European time in Germany, UTC + 10 is a local time in Sydney and UTC - 5 in New York.

Due to daylight saving time, Great Britain has UTC + 1 and Germany UTC + 2.

The website http://www.worldtimezone.com shows the time zones and the local times in real-time.