The European Aviation Safety Agency approved the Airbus A320 family of aircraft for Category IIIb approaches using a microwave landing system (MLS), Airbus said this week. First customer, British Airways, will implement MLS at London's Heathrow airport on A320s and A321s. MLS uses microwave signals that are less susceptible to interference than the current Instrument Landing System (ILS). Cat III b approval enables airports to allow precision approach and landings in very low visibility conditions, with the decision height lower than 50 feet, Airbus said. The MLS system was a joint development by industry partners including Thales, British Airways and the UK and French national Airport and Air Transport authorities. Thales manufactured the on-board MLS receiver, hosted in a Multimode receiver (MMR), and the airport MLS ground station. MLS operations are similar to those using ILS, with straight approaches in the runway axis along a three-degree slope. The aircraft is equipped with capture and tracking antennae and an avionics software suite, while on the ground, each runway has an MLS ground station.