As of March 5, according to new International Civil Aviation Organization (ICAO) rules, English proficiency is now be the required of all pilots and air traffic controllers. In the past, controllers and pilots could communicate in a local language if both spoke it, even though English was the most common standard. More than anything else, this affects communications at major international airports. A number of air disasters have been attributed to language barriers. A pilot I know was once taxiing to the runway at General Mariano Escobedo International Airport in Monterrey, Mexico, and was instructed — in English, as he flies for a U.S. airline — to proceed to a particular location. Over the radio, he heard the tower, in Spanish, direct an Aeromexico MD-88 to the same location. The U.S. pilot speaks Spanish fluently, so he was able to radio the tower and request clarification. Had he not spoken Spanish, there might have been a collision. The implementation of this rule is a concrete step toward making air travel safer.
English to become compulsory for pilots [Telegraph]