CHAPTER 11 SPECIAL INSTALLATIONS

101. Alarm System

1. Alarm system should be provided which announce at the craft's control position, by visual and au- dible means, malfunctions or unsafe conditions. Alarms should be maintained until they are ac- cepted and the visual indications of individual alarms should remain until the fault has been cor- rected, when the alarm should automatically reset to the normal operating condition. If an alarm has been accepted and a second fault occurs before the first is rectified, the audible and visual alarms should operate again. Alarm systems should incorporate a test facility.

(1) Emergency alarms giving indication of conditions requiring immediate action should be distinc- tive and in full view of crew members in the operating compartment, and should be provided for the following:

(A) activation of a fire-detection system;

(B) total loss of normal electrical supply;

(C) overspeed of main engines;

(D) thermal runaway of any permanently installed nickel-cadmium battery

(E) wing stall; and

(F) linear or angular accelerations exceeding 90% of the design limitations of the craft for more than one second.

(2) The alarm required by (1) (E) should operate with sufficient safety margin to prevent in-

advertent stalling and should be clear and distinctive to the pilot in straight and turning flight. The stall warning may be recognized either through the inherent aerodynamic qualities of the craft or by a alarm device and should begin at a speed exceeding the stalling speed (i.e, the speed at which the craft stalls or the minimum speed demonstrated) by seven percent.

(3) Additional alarms and warning signals should be fitted in the operating compartment. These may include:

(A) exceeding the limiting value of any craft, machinery or system parameter other than engine

overspeed

(B) failure of normal power supply to any powered control devices

(C) activation of any bilge alarm

(D) operation of any automatic bilge pump

(E) failure of compass system

(F) low level of a fuel tank contents

(G) fuel oil tank overflow

(H) extinction of any navigation light

(I) low level of contents of any fluid reservoir the contents of which are essential for normal craft operation

(J) failure of any connected electrical power source

(K) failure of any ventilation fan installed for ventilating spaces in which inflammable vapours may accumulate, and

(L) fuel line failure

(4) All warnings required by (1), (2) and (3) should be provided at all stations at which control functions may be exercised.

2. The alarm system should meet appropriate constructional and operational provisions for alarms.

required

3. Monitoring equipment for the passenger, cargo and machinery spaces for fire and flooding should, as far as practicable, form an integrated sub-centre incorporating monitoring and activation control for all emergency situations. This sub-centre may require feedback instrumentation to indicate that actions initiated have been fully implemented. However, individual operating center may be accepted instead of this sub-centre for small WIG ships.

102. Aerodynamic Stabilization System

1. Definitions

Where conflict exists between the aerodynamic meaning of terms where in this Guideline, the aerodynamic meaning is intended to be

used in this chapter and else- followed.

Guidance for WIG ships(Wing-In-Ground Effect Ships) 2012 55

(1) "Stabilization system" is a system intended to stabilize the main parameters of the craft's alti- tude: roll, flight trim, pitch, heading and altitude and control the craft's motions: roll, pitch, yaw and heave. This term excludes devices not associated with the safe operation of the craft.

(2) The main elements of a stabilization system may include the following:

(A) devices such as rudders, foils, flaps, skirts, fans, tilting and steerable propellers, pumps for moving fluids.

(B) power drives actuating stabilization devices, and

(C) stabilization equipment for accumulating and processing data for making decisions and giving commands such as sensors, logic processors and automatic safety control.

(3) "Stabilization device" means a device as enumerated in (2) (A) with the aid of which forces for controlling the craft's altitude are generated

(4) "Automatic safety control" is a logic unit for processing data and making decisions to put the

craft into the displacement or other safe mode if a condition impairing safety arises.

(5) "Automatic control system" is a system which enables the craft's heading and altitude to be maintained without operator input.

2. General requirements

(1) Stabilization systems should be so designed that, in case of failure or malfunctioning of any one of the stabilization devices or equipment, it would be possible either to ensure maintaining the main parameters of the craft’s motion within safe limits with the aid of working stabilization

devices or to put the craft into the displacement or

other safe mode.

(2) In case of failure of any automatic equipment or stabilization device, or of its power drive, the parameters of craft motion should remain within safe limits.

(3) Craft fitted with an automatic stabilization system should be provided with an automatic safety control unless the redundancy in the system provides equivalent safety. Where an automatic

safety control is fitted, provision should be made to override it and to cancel the override from

the main operating station.

(4) The parameters and the levels at which any automatic safety control activates to decrease speed and put the craft safely in the displacement or other safe mode should take account of the demonstrated safe values of altitude, roll, flight trim, pitch, yaw and associated accelerations ap- propriate to the particular craft and service; also to the possible consequences of power failure for propulsion, lift or stabilization devices.

(5) The parameters and the degree of stabilization of the craft provided by an automatic stabiliza- tion system should be demonstrated to be satisfactory, having regard to the purpose and service conditions of the craft.

3. Longitudinal and height control system

(1) Craft fitted with an automatic stabilization system should be provided with an automatic safety control unless the redundancy arrangements are such that this control is not required by 2 (3). Foreseeable malfunctions should have only minor effects on automatic control system operation and should be capable of being readily counteracted by the operating crew.

(2) The parameters and levels at which any automatic safety control activates to decrease speed and put the craft safely into the displacement or other safe mode should take account of the safety

levels and of the safe values of motions appropriate to the particular craft and service.

56 Guidance for WIG ships(Wing-In-Ground Effect Ships) 2012