Electronic emergency equipment requirements.

Equipment in the cabin can include:

* Automatic emergency warnings on pre-recorded audio equipment.

* Floor path lighting (in the floor or fitted to seats close to floor level).

* Emergency exit lighting.

* Battery powered megaphones - scale Y of the ANO.

1 for aircraft with > 19 and < 100 passengers.

2 .. > 99 .. < 200 ..

3 .. > 199

Emergency lighting - inside (including floor path) and outside the aircraft to facilitate passenger evacuation in an emergency - scale Z. Hand held torches - scale G.

Water proof torches as part of life raft equipment - scale K. Survival beacon radio transmitters - scales K, U & V. Must meet the requirements of TSO-C91 and be positioned near an exit. Underwater sonar device - scale T, A crew intercommunication system - scales N & Y. On all flights where the aircraft carries a flight crew of more than one person If there is a lower deck that may be occupied during taxiing or flight (but not take-off or landing) a two way voice communication system must be provided, also an aural emergency alarm must be fitted together with a PA system (if one is fitted to the aircraft). Emergency illuminated exit markings.

Public address system. Scale Y. For aircraft with more than 19 passengers. Must have at least one microphone for cabin crew use (to be accessible by a flight attendant whilst seated in any seat next to the door) at each passenger door.

In general the ANO states what equipment is to be carried on specific aircraft types/categories and on specific flights (by night or by day or over water for example) and EASA25 states the specification that equipment has to meet.

In general all the scales quoted above (G, K, N, T, U, V, Z) are applicable to public transport aircraft. Some small variations do exist and the reader is directed to the ANO should further details be required. Specifications in EASA25 on electrical/ electronic equipment include the following:

Lightning Protection. Metal components/LRUs must be bonded and non metal units must be so designed so the strike current goes round the unit and/or the effect of strike current is minimal.

Electrical Bonding. Must be fitted to equipment to:

* Protect the aircraft from lightning strikes.

* Prevent the dangerous accumulation of electro static charge within parts of the aircraft.

* Minimise the risk of electric shock to personnel.

* Provide a current return path for aircraft having an earth electrical system (single pole).

* Reduce interference to systems such as radios etc.

Passenger Signs. At least one No Smoking sign and one seat belt fasten sign (using letters or symbols) when illuminated to be legible to each person seated in the passenger cabin under all probable conditions of cabin lighting. These signs must be operable from either pilot's seat position.

Passenger Emergency Exit Markings. Emergency exits are classified in general according to size with a Type A being the largest (normally an ordinary passenger door). All the other exists are classified in general in decreasing order of size starting with the largest as a Type I through to the smallest a Type IV.

All Type A and Type I emergency exit handles must be self illuminated with an initial brightness of 160 microlamberts or be well illuminated by the emergency lighting - even in conditions of severe passenger over-crowding. Type III emergency exit handles must be self illuminated with an initial brightness of 160 microlamberts.

If the handles are covered the cover must be self illuminated to the same brightness.

Emergency Exit Markings (scale Z). Each emergency exit must be conspicuously marked to show means of operation, location and means of access.

For aircraft with a passenger seating configuration of 10 or more (excluding the pilot) the emergency exits must have a locator sign and a marking sign which must have red letters at least P/2 inches high (31.1mm) on an illuminated white background with an area at least 21 square inches (135.48cm squared) excluding letters. The lighted background to letter contrast must be 10:1. These signs must be internally electrically illuminated with a back ground brightness of 25 foot lamberts.

Floor Path Lighting (scale Z). Floor proximity emergency escape path lighting must provide the passenger with the shortest route fore or aft of his/her seat to an escape exit where all light sources above 4ft (1.2m) from cabin floor level are totally obscured (by smoke for example).

Exterior Emergency Lighting. Exterior emergency lighting is required at each over- wing emergency exit and each non over-wing emergency exit.

For over-wing exits an illuminated area is required where the passenger makes his/her first step on the wing (2ft square area at 0.03 foot candle power) and 0.05 foot candle power lighting for the non slip walk area for a Type A exit. Where the passenger first makes contact with the ground a 0.03 foot candle power lighting is required. This lighting to be available for a minimum period of 10 minutes.

Power Supplies. Power supplies may be common to both normal and emergency lighting systems but the systems themselves must be independent.

The systems must be so designed that they will take the normal g loads of the aircraft, maintain a supply for the minimum required times under any foreseeable conditions and not cause a hazard when operated in emergency conditions.

Switching. Except where there is an escape chute with a fully automatic independent lighting system the emergency lighting system must be controlled from the flight deck plus one cabin crew station.

The flight deck control switch must have ON, OFF and ARMED. When power is on the aircraft a warning light is on if the system is not armed. A warning light comes on if power is interrupted with the system switched on or armed. There must be means to safeguard against inadvertent operation from the armed or on positions.

Any charging equipment used for charging the emergency batteries must preclude the possibility of battery discharge back into the system and if the fuselage breaks in two on crash landing then not more than 25% of all the electrically operated emergency lights should be rendered inoperative - other than those directly damaged by the event.

Equipment This includes all equipment on the aircraft including emergency equipment and IFE equipment. All equipment falls under one of two categories:

* Controlled equipment. Equipment on which the safe operation of the aircraft depends and which is normally prescribed by Civil Aviation Authority requirements (the ANO) and must be approved. Typically, in the context of this book, it would include all safety equipment on the aircraft together with PA systems etc.

* Uncontrolled equipment. Normally not required to be approved because failure of which would not adversely affect the safe operation of the aircraft. However, any equipment fitted to an aircraft (IFE for example) needs to meet the requirements as laid down in British Civil Airworthiness Requirements (BCARs) section A.

This states that any equipment fitted to the aircraft as Uncontrolled items must be fitted by an approved organisation who submits a certificate to the CAA that the equipment will not effect the safe operation of the aircraft and is so installed that its failure will not endanger the aircraft or its occupants.

In general equipment must perform its intended function under all normal foreseeable aircraft operating conditions (temperature, vibration, g loads etc). System mal function warnings must be provided and the controls etc so designed as the minimise crew errors.

Systems and their batteries must perform correctly over a period of time to include the full duration of the longest flight at maximum regulated voltage in the most adverse temperature conditions.

Any equipment whose functioning is required for aircraft certification (controlled equipment) and that requires a power supply is an essential load on the electrical supply system. The power supply system must be capable of supplying the total load over a period of time during a combination of load requirements. These include:

* After failure of any one engine on a two engined aircraft.

* After failure of any two engines on a three or more engined aircraft.

* After failure of any one prime mover, power converter or energy storage device.

When operated electrical/electronic equipment must not interfere with any other systems.