Cab rank

A cab rank is a primarily British term for taxi stand, although the phrase has three other uses:

During World War II, the Royal Air Force discovered that the most convenient and assured way of using attack aircraft to destroy ground targets was by having a series of three aircraft, each in turn directable by the pertinent ground control by radiotelephone. One aircraft would be attacking, another in flight to the battle area, while a third was being refuelled and rearmed at base. If the first attack failed to destroy the tactical target, the aircraft in flight would be directed to continue the attack. The first aircraft would land for its own refuelling and rearming once the third had taken off. This method of nearly continuous attack was called the "cab rank system." It had some consequences post-war; for example, the Hawker Hunter fighter aircraft, useful for ground attack, had its four 30 mm cannon contained in a module in its fuselage. When the aircraft landed, it was rearmed by the module being simply swapped, rather than by opening panels in the wings to thread in chains of cartridges as before.

In English law the expression 'cab rank rule' rule refers to the obligation of a barrister to accept any work in a field in which he professes himself competent to practise, at a court at which he normally appears and at his usual rates.