waverley aerospace publications

Blind Landing - A History

This book describes the development of the blind and automatic landing of aircraft in poor visibility conditions. The main driver initially was civil aircraft operations but the requirement to recover bombers returning to fog bound bases in Britain in WWII and later the increasing requirements of military operations helped to maintain the pace of development. The arrival of jet powered airliners and the increasing need for safety and reliability then led to civil operations in a range of weather conditions established by ICAO.

The book covers the early flight research conducted prior to WWI, the blind landings made by Lt Doolittle with his Consolidate Husky aircraft, the automatic landings by Capt. Crane in the lumbering Fokker YC-14B, and the work on unmanned aircraft as targets for naval gun practice and as guided weapons in the inter war years.

The development of the US CAA VHF guidance system pre-WWI and the wartime SC-51, the forerunner of today’s ILS, during WWI for the USAAF in competition with systems operating in the microwave band is described in detail. The SC-51 with its UHF glide path tested at RAF Defford was cleared for automatic approaches by USAAF bomber aircraft returning to their home bases from Germany in fog. Toward the end of the war, the first automatic landing in the UK was achieved using a refurbished Boeing 247D aircraft equipped with SC-51 and a US electric autopilot and interface equipment developed by TFU personnel at RAF Defford.

In 1946, the UK government acknowledged the need for future military aircraft to counter the Soviet threat and formed the Blind Landing Experimental Unit (BLEU) to investigate and develop scientifically the means of recovering aircraft in fog conditions. This resulted in a system to land the V-bombers automatically in poor weather.

The arrival of jet powered aircraft saw the requirement for automatic approach and landing extended to civil aircraft such as the Caravelle and the Trident but with increased levels of safety and availability which necessitated fail operational, digital multiplexed flight control systems, guidance system and displays, including head up displays.

The SC-51 ILS was adopted by ICAO and further developed to meet various forms of interference and multipath and siting problems and permit world-wide operation, while overcoming the challenges of competing systems in the microwave band. The net result was that modern civil aircraft are delivered capable of automatic or blind landing in the worst weather categories (ICAO Category 3) or better*.

In addition, the book encompasses new forms of guidance, particularly enhanced vision systems using infra-red, and millimetric wave imaging systems and head up displays and map based synthetic vision systems. It also addresses the problems of modern control system design, certification methods, and training with specific reference to the Boeing B787, B377MAX and B777 aircraft systems and the problems caused by the world-wide Covid-19 pandemic which arrived in 2019 and significantly closed down civil aviation world-wide for a significant period until late 2021.

The book has 560 pages and is well illustrated by pictures and diagrams. It may be purchased for £35, including postage and packaging (UK only). Prices for Europe and the Rest of the World are available on request.

* A category III A/B/C approach is a precision instrument approach and landing with a decision height lower than 100ft (30m)/ 50ft (15m)/no DH and a runway visual range not less than 700ft (200m)/ 250ft (75m)/ no RVR limitation respectively.