Wing-in-ground (WIG) craft are supported in their main operational mode solely by aerodynamic forces which enable them to operate at low altitude above the sea surface but out of direct contact with that surface. Accordingly, their arrangement, engineering characteristics, design, construction and operation have a high degree of commonality with those characteristics of aircraft. However, they operate with other waterborne craft and must necessarily utilize the same collision avoidance rules as conventional shipping.
WIG craft is a multimodal craft which, in its main operational mode, flies by using ground effect above the water or some other surface, without constant contact with such a surface and supported in the air, mainly, by an aerodynamic lift generated on a wing (wings), hull, or their parts, which are intended to utilize the ground effect action.
WIG craft are categorized according to the following types:
- type A: a craft which is certified for operation only in ground effect. Within prescribed operational limitations, the structure and/or the equipment of such a craft should exclude any technical possibility to exceed the flight altitude over the maximum vertical extent of ground effect;
- type B: a craft which is certified for main operation in ground effect and to temporarily increase its altitude outside ground effect to a limited height, but not exceeding 150 m above the surface, in case of emergency and for overcoming obstacles; and
- type C: a craft which is certified for the same operation as type B; and also for limited operation at altitude exceeding 150 m above the surface, in case of emergency and for overcoming obstacles.
In order to provide as much guidance as possible to those involved in the design, construction and operation of WIG craft, the Guidelines have been prepared in three parts:
- part A provides general information applicable to all craft;
- part B includes provisions that may be subordinate to measures developed through the safety assessment recommendations of part C; and
- part C details the safety assessments required for all craft.
The interim guidelines were intended to provide as much guidance as possible to those involved in the design, construction and operation of WIG craft.
IMO and the International Civil Aviation Organization (ICAO) have agreed that any WIG craft capable of sustained flight outside the influence of ground effect should also be subject to the rules and regulations of ICAO. Other craft, including those with limited “fly-over” capability, should be covered only by the maritime regulatory regime.
MSC/Circ.1162 General principles and recommendations for knowledge, skills and training requirements for officers on Wing-In-Ground (WIG) craft is intended to primarily assist Member governments in developing their national requirements for qualification and certification of officers on a WIG craft operating in both displacement and ground-effect modes.
Amendments to the Convention on the International Regulations for Preventing Collisions at Sea, 1972, adopted in November 2001, entered into force on 29 November 2003. The amendments to existing Rules include new provisions relating to Wing-In Ground (WIG) craft.