CIRCULAR Circular 121-AN/90 IMPLEMENTATION OF ALL WEATHER OPERATIONS Approved by the Secretary General and published under his authority INTERNATIONAL CIVIL AVIATION ORGANIZATION MONTREAL CANADA
Published in separate English, French, Spanish and Russian editions by the Inter- rtationul Civil Aviation Organization. All corresporzdence, except orders and sub- scriptioizs, should be addressed to the Secretary Genercrl of ICAO, International Aviution Building, 1080 University Street, Montreal 101, Quebec, Canada. Orders for this publication should be sent to one of the following addresses, together with the appropriate remittance by bank draft or post office money order in U.S. dollars or the currency of the country in which the order is placed or in a freely convertible currency Canada Information Canada, Ottawa, On- Mexico Representante de la OACI, Oficina t arlo. NorteamCrica y Caribe, Apartado postal 5-377, Mtxico 5, D.F. Egypt Arab Republic of ICAO Represen- tative, Mddle East and Eastern African Pm Representante de la OACI, Oficlna Office, 16 Hassan Sabri, Zamalek, Cairo. SudamCrica, Apartado 41 27, Lima. France ReprCsentant de I'OACI, Bureau Europe, 3bis, villa Emile-Bergerat, 92 Neuilly- sur-Seine. India Oxford Book and Stationery Co., Scindia House, New Delhi or 17 Park Street, Calcutta. Japan Japan Civil Aviation Promotion Foundation, No. 38 Shiba Kotohira-Cho. \linato-Ku. Tokyo. Senqal Reprtsentant de I'OACI. Bureau Afrique, Boite postale 2356, Dakar. Sweden C.E. Fritzes Kungl. Hovbokhandel, Fredsgatan 2, Box 16356, Stockholm 16. Thailand ICAO Representative, Far East and Pacific Office, P.O. Box 614. Bangkok. United Kingdom Her Majesty's Stationery Office, P.O. Box 569, London, S.E. I. International Civil Aviation Organization Attenttn Distribution Officer, lnternatonal Avation Budding, 1080 University Street, Montreal ldl, Quebec, Canada. Do you receive the lCAO BULLETIN The ICAO Bulletin contains a concise account of the actrvrtres of the Organization as well as articles of interest to the aero- nautical world. The Bulletin will also keep you up to dote on the latest lCAO publications, their contents, amendments, supplernenfs, corri- gendo, and prices. Available in three raparate oditlons English. French and Spanish. Annual subscription. U.S. 9.00 surface mail U.S. 17.00 air nail.
t an early stage in its work, the All Weather Operations Panel Amp recognized the potential usefulness of a document consolidating States1 and operator's experience in the preparation for, approval and implernentatin of All Weather Operations. At its Fourth Meeting in Montreal in early 1971, the Panel considered that the time had arrived for the preparation of such a document based on the considerable experience which had then accumulated regarding operations jn Category I1 conditions, and an appropriate recommendation was made to the Air Navigation Commission. That recommendation was approved by the Commission, and the Panel undertook the preparation of the document as part of its ongoing Work Bogramme. A Working Group of the AWOP, though the co-operation of States and operatars, had available to it a great deal of related information. It pre- pared a comprehensive working paper for consideration by the Fifth Meet- of the AWOP, held in Montreal, Canada. 22 October to 2 November 1973. The Panel further refined the material. and recommended to the Air Navigation Commission its publication as an ICAO Circular. The Air Navigation Commission, on 12 February 1974, approved the related recommendation of the Panel, and requested the Secretary General to publid this Document,
TABLE OF CONTENTS Introduction General concepts 2.1 General 2.2 Benefits 2.3 Syster, concept 2. Eqipnent Jeoign ccnce5 ts 2.5 Operations Ground enviroiment 7.1 lcctronic gidance system T.2 Visual aids 3.3 Run.raysandtvays 3.4 Pre-thseshold terrain 3.5 Secondary power scpplics 3.6 Air traffic service .TS -'. .7 Aeroriautical infor1atior. service AIS 7.8 I.letcoroloy . Obstacle c1eartnce 1iiitn rid obstacle limitation surfaces 3.1 Essential vehicle mnoeuvring The aircraft syste 'c .l Genersl re.i1.ir8rnents 4.2 I.liniiuni quiii,lent reqlircments lr .3 Airborne system ai,.rov.xl 4. '1 Iaintenm,ce . Sumnary of sone States' eqipent reqirs.ents 4.5 Sgnrulsry of .olc states' aircraft 3erfornance i-eqir,ments 5.1 G2neral '3.2 Tle oerctions manual 5.- Procedures for the introuction of low i,ei.tler minima operations