Section 12
Lighting Systems
Section 12
Lighting Systems
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INSTRUMENT LIGHTING & INDICATOR LIGHTS
General
All the instrument dials and control units are illuminated by lights built into the plexiglass covers with each
light having two bulbs.
Each bulb is powered by a separate DC supply, one from a Primary bus bar and the other from a
Secondary bus bar so that, should generated DC supply fail, only one bulb is lit and the battery drain is
reduced.
There are four lighting zones, each powered by their own Lighting Power Unit (31L1 to 31L4) and
controlled by Lighting Control Units (61L1 – 61L4) located on the overhead panel.
Certain instruments (HSI and DME) require a 5-volt DC power supply for their lighting and this is
provided by a PCB in the electrical cupboard which converts 28 volts DC to 5 volts DC.
Control Units (61L1 - 61L4)
The four control units, located as shown in Figure 1, contain an ON/OFF switch and dimmer rheostat for
the panel lighting and a test button with DIM/NORMAL switch for the indicating lights.
Note - the instrument panel indication lights do not have indicating light controls as these are provided by
the TEST & DIM buttons on the CWP.
These units receive the power supplies from the Power Units and then control these supplies (ON/OFF &
brightness) back to the Power Units for distribution to the lights. The indicating lights supplies follow a
similar route.
INSTRUMENT PANEL - CO-PILOT
OVERHEAD PANEL
LIGHTING
WARNING
DIM
OFF
OFF
TEST
NORM
ON
LIGHTING
ON
PEDESTAL AND STRIP
WARNING
DIM
NORM
LIGHTING
OFF
TEST
ON
INSTRUMENT PANEL - PILOT
LIGHTING
OFF
ON
Figure 1 – Cockpit Lighting Control Switches
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Lighting Systems
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Power Units (31L1 - 31L4)
Three of these units are located under the cockpit floor and the other is above the Cabin roof just aft of
the Electrical Cupboard. Each unit contains 10 PCBs arranged to distribute the power to the lights with
one of these boards controlling the internal circuits common to both lighting and indicating lights supplies.
Five of the PCBs operate the instrument lighting circuits and can supply 48 circuits per Power Unit (32
double and 16 single). The remaining 4 PCBs activate the indicating lights and provide 36 circuits per
Power Unit.
Electrical Power Supplies
The following DC circuit breakers protect the Primary and Secondary power supplies to the lighting and 5
volt power units.
PP4
INST. PANEL LT.
INST. PANEL LT.
OVERHEAD LT.
CONSOLE LT.
5V LT.
- to 31L4
- to 31L1
- to 31L3
- to 31L2
- to 5V PCB
(Pilots Inst. Panel Lighting)
(Co-Pilot Inst. Panel Lighting)
(Overhead Panel Lighting)
(Pedestal & Strip Lighting)
2PP5
INST. PANEL LT.
INST. PANEL LT.
OVERHEAD LT.
CONSOLE LT.
5V LT.
- to 31L4
- to 31L1
- to 31L3
- to 31L2
- to 5 volt PCB
(Captains Inst. Panel Lighting)
(Co-Pilots Inst. Panel Lighting)
(Overhead Panel Lighting)
(Pedestal & Strip Lighting)
2PP6
SIGNAL
- to 31L1
31L4 (Indicating Lights)
1PP5
SIGNAL
- to 31L1
31L4 (Indicating Lights)
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COCKPIT LIGHTING
Dome
Light
Utility
Light
Dinghy Light Switch
and
Storm Light Switch
Co-Pilots
Map Light
and Switch
Captains
Map Light
and Switch
Figure 2 – Cockpit Lighting
Utility Light
This portable light, fitted with a coiled power lead, can be positioned in a slick-stop mounting socket
either on the overhead panel or on the bulkhead behind the co-pilot. ON/OFF switching and brightness
is controlled by a rotary switch at the rear end of the light. At the front of the light, a rotary control can
move a red filter across the lens for night time illumination.
The light is powered from PP1 bus bar, via a circuit breaker, and has its own return to the battery
negative so that it is permanently 'live' thus ensuring it can be operated with the battery positive and
negative contactors de-energised.
After the aircraft is shutdown and all switches are turned ‘OFF’ the utility light must be checked to ensure
that it is turned ‘OFF’.
Dome Light
Designed to give a soft white light throughout the cockpit, the Dome light is positioned on the overhead
panel at the rear left hand side. The control switch is fitted above the Captain on the internal lighting
switch panel and it is marked ‘Cockpit’ and not ‘Dome’. See Figure 3.
The power supply is from 2PP6 bus bar and a supply can be obtained from the Standby Battery in an
emergency.
Map Lights
Two swiveling spotlights are provided on the overhead panel directly above each pilots lap for reading
maps and documents. Each light has it's own ON/OFF switch and both are powered via a single circuit
breaker from 1PP6 bus bar.
Storm Lights
This light, above the Captains left shoulder is designed to illuminate a given area of the instrument panel
to reduce the contrast due to Lightning flashes. The power supply is from PP4 bus bar and the ON/OFF
control switch is mounted at the rear of the overhead panel on a small vertical bulkhead just in front of
the Heater Controls. See Figure 2.
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CABIN LIGHTING
LIGHTING
CABIN
EMERG
LIGHTS
COCKPIT
OFF
OFF
OFF
DIM
ON
ON
ORDINANCE LIGHTS
SAFETY
BELTS CIGARETTES
BRT
EXTERNAL LIGHTING
FIX FLOODS
OFF
POS
A /COLL
WHITE
LANDING LIGHTS
PILOT
TLT
OFF
Not Used
on Tiger
OFF
ON
ON
RED
TLT
CO-PILOT
Figure 3 – Cabin and External Lighting Switches
Cabin Lighting
A twin row of fluorescent tubes mounted in the cabin trim at either side above the passengers gives
concealed type lighting to illuminate the Cabin. The tubes are powered from the secondary bus bar via
circuit breakers with each tube having its own static inverter to provide the necessary AC power. A
3-position switch is mounted on the overhead panel, alongside the cockpit light switch. The three
positions are OFF, BRT and DIM.
Emergency Cabin Lights
Fitted into the cabin roof are four lights for emergency illumination of the cabin. These lights are normally
powered by 1PP6 bus bar and controlled by a switch on the overhead panel. Should the normal power
supply fail (or be shed) then the Standby Battery will automatically illuminate the lights irrespective of
control switch position.
Ordinance Lights (Cabin Signs)
The NO SMOKING and SEAT BELT signs are controlled by two switches on the overhead panel. The
lights are mounted in the trim on the rear face of flying control cabinet and in the roof at suitable positions
to enable all passengers to see them. They are powered by Primary and Secondary bus bars and, in an
emergency, can be powered by the Standby Battery. The switches must be placed ‘ON’ to operate
under emergency supply.
Passenger Reading Lights
Above each passenger seat is a reading light controlled by its own push button ON/OFF switch. The
lights are powered by 2PP5 bus bar.
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Lighting Systems
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Cockpit and Cabin Lighting Power Supplies
The following circuit breakers protect the electrical power supplies for the Cockpit and Cabin Lights.
PP1
UTIL. LT.
- Utility Light (always live)
2PP6
PILOT O/HEAD LT.
- Dome Light
1PP6
EMERG. EXITS ORD. LTS.
INDIV. LTS
-
- Cabin Emergency Lights
- No Smoking & Seat Belt Signs
- Map Lights
PP4
STORM LT.
-
- Storm Light
1PP5
CARGO LT
-
- Cabin Lighting (neon tube supply)
2PP5
CARGO LT.
READING LTS. ORDINANCE LTS.
- ON/OFF control relay supply for Cabin Lighting
- Passenger reading lights.
- Secondary supply No Smoking & Seat Belt lights.
EXTERNAL LIGHTING
The external lighting consists of 1.
2.
3.
4.
5.
6.
Landing Light
Fixed Floodlights
Anti-Collision Lights
Position Lights
Dinghy Lights
Hold Light
Control Switches
The control switches for the external lights are positioned as shown in Figure 3.
Forward Landing Light
A retractable Landing Light is fitted under the nose of the aircraft and when lowered, the light can be
rotated through 360°. A DC motor, fitted with limit switches, actuates the extension and retraction and
another DC motor, fitted with a centering switch operates the rotational movement. The 600 watt bulb is
powered by 2PP6 bus bar whilst the Pilots and Co-Pilots control power is from 2PP6 and 2PP5 bus bar
respectively. The maximum elevation of the light when extended is 30° upward but this should be
avoided as the heat generated by the bulb could damage the nose flotation unit.
The operation of the light is controlled by a
switch and 4-way button on each collective
lever. When the light is switched ‘ON’ a blue
warning light on the overhead panel is
illuminated.
Landing Light
On/Retract Switch
4-Way Position
Control Switch
Figure 4 – Landing Light Control Switches
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Lighting Systems
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The lamp and orientation motors are designed for intermittent use and the following maximum operating
times should not be exceeded.
Lamp
Motor
- 15 minutes ‘ON’ then 45 minutes OFF
- 3 minutes ‘ON’ then 17 minutes OFF
Normal retraction and extension times = 12 seconds
Full azimuth rotation time = 17 seconds
The lamp is switched ‘ON’ by placing either collective lever switch to the ‘ON’ (forward) position. It can
then be extended and rotated by operation of either of the collective lever 4-way buttons but the Captains
button always over-rides the Co-pilots. Retraction can be made by holding the 4-way button aft but to
alleviate this the ON/OFF switches are provided with a spring-loaded position aft. A short pulse to this
position by either switch will centre and retract the light automatically. However, the light will only
extinguish when both switches are in the ‘OFF’ position.
Fixed Flood Lights
Mounted in each sponson is a fixed 450-watt light encased by a perspex leading edge panel. These
lights are powered from the Secondary bus bar and controlled by a relay operated by a control switch on
the overhead panel. The relay is also powered from the Secondary bus bar.
Anti-Collision Lights
Two red anti-collision lights are fitted to the aircraft, one on top of the tail pylon and the other under the
tail boom. Both are powered by 2PP6 bus bar via a common 3-position switch on the overhead panel.
The upper light is combined red and white strobe light operated by capacitors, whilst the lower one is a
rotating mirror light.
The 3-position switch is marked A/COLL WHITE, OFF and RED.
In the RED position, both lights will be red. In the A/COLL WHITE position the upper light will operate as
a white strobe but the lower light will remain red.
Position Lights
A red light is mounted in the tip of the port sponson, a green light in the starboard sponson, and a white
light in the top of the trailing edge of the tail pylon. These lights are powered via a single circuit breaker
from 1PP5 bus bar and controlled by a switch on the overhead panel.
Dinghy Lights
Positioned just aft of the main door on either side, these lights are designed to illuminate the door area
should a night ditching be necessary and the dinghies deployed.
They are powered from PP1 bus bar and controlled by a switch on the overhead panel adjacent to the
Storm Light switch. The power supply has its own return to the battery negative and is therefore
available even if the battery contactors are de-energised.
Hold Light
Two 'dome' type lights are fitted in the rear baggage bay and controlled by a magnetic switch on the lefthand side of the baggage bay door opening. The switch is self-holding in the ‘ON’ position and when the
door is closed the indicating micro-switch cancels the self hold and the lights extinguish. The lights are
powered from 1PP6 bus bar via a single circuit breaker.
Note – This light will extinguish when both engine SSLs are retarded due to normal load shedding.
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External Lighting Power Supplies
The following circuit breakers protect the power supplies for the external lights.
PP1
DINGHY LT.
- Dinghy Lights (always 'live')
2PP6
ANTI-COLT LT
LOWER ANTI-COLL
NOSE LAMP LIGHT
PLT. LAND. LIGHT
- Upper Anti-Collision Light
- Lower Anti-Collision Light
- Landing Light Bulb power
- Pilots control power for Landing Light orientation
1PP6
HOLD LT.
- Baggage bay lighting
1PP5
POSITION LTS.
LAND LT. LH.
- Position Lights
- Left Hand Fixed Flood bulb power
2PP5
LAND LT. RH.
CO-PILOT LAND LT.
LAND LT.
- Right Hand Fixed Flood bulb power
- Co-Pilots control power for Landing Light orientation
- Control power for ON/OFF relay for Fixed Floodlights.
EMERGENCY EXIT LIGHTING - EXIS
General
All Bristow AS332L Helicopters are fitted with Emergency Exit Lighting. There are 3 different types of
lights. They are called EXIS 1, EXIS 2 and EXIS 3. Their purpose is to outline the emergency exits,
escape windows and emergency exit door handles, primarily to assist escape if the helicopter capsizes
after an emergency landing on water.
EXIS 1
EXIS 1 lights are 394-mm long strips of Light Emitting Diodes (LED's). They are along the sides of the
designated emergency exits and can be switched ‘ON’ by means of a guarded switch marked EXIS
situated on the centre pedestal. They can also be turned ‘ON’ by immersion of the battery units in salt or
fresh water.
E
X
I
S
The Crew Emergency Exits are also fitted with EXIS 1 but these are only activated by immersion of the
battery units.
When illuminated, the lights are ‘ON’ steady.
EXIS 2
EXIS 2 lighting ('L' shaped LED strips) is used to mark the corners of Escape Windows. Activation is by
immersion of the battery units fitted adjacent to each window.
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EXIS 3
EXIS 3 lighting (a square lens containing a LED) is used to identify the position of the Cabin Door
Emergency Jettison handle on the port and starboard doors. The lens is situated inside the cabin door
jettison handle.
Activation is by immersion of the battery units located adjacent to each light. They flash when activated.
Battery units are positioned midway between the cabin floor and roof and will illuminate the lights for a
minimum of 20 minutes under emergency conditions.
NOTE – The EXIS lights must only be selected ‘ON’ in an emergency. The battery life is only 20 minutes,
so operation for anything other than emergency is not permitted.
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INTENTIONALLY BLANK
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