revision preference src: For example, the IATA code for London's Heathrow Airport is LHR and its ICAO code is EGLL. <SEP> tgt: For example, people who fly from Heathrow airport, are likely to know it best as either Heathrow, or by its IATA code: LHR. <SEP> They are less likely to know its ICAO code: EGLL.