11.14 Lights Flashcards
What are the 3 categories that lights are loosely split in to
- Internal
- External
- Emergency
How are most of the aircraft lights powered
By AC or DC power
What do some AC unit lights incorporate to alter supply or intensity of power
They have their own auto transformers to step down aircraft 115v electrical power down to the lights working voltage or from 28v to 10v or 6v
What ATA chapter is lights
ATA 33
What is the purpose of navigation lights
To mark the aircrafts position and indication of its orientation with reference to its observer. Nav lights are mandatory and required by law
What are the colours and angles of the nav lights
- Red: visible to 110 degrees for the left
- Green: Visible to 110 degrees for the right
- White: Visible from back 70 degrees to left and right
=360 degrees
What power will nav lights be supplied by
28v AC or DC power
What can be used to power the nav lights on the ground
They can be powered by AC or by DC from the batteries or by external power
Where are the anti collision lights positioned
On the fuselage top and bottom
What is the normal rotational speed of the rotating beam lighting and what frequency of flashes per min would that give
Normal rotational speed of 40-45mph and a frequency of 80-90 flashes per min
How are the rotational beam lighting powered
28v DC with a DC motor
How do strobe lights provide light
They provide a high intensity flash by using a set of capacitors to store up an electrical charge and then releasing the charge across a gap inside a gas filled tube to produce a flash of light
What is the flashing frequency of strobe lights
60-70 flashes per min
How are strobe lights powered
Either 28v DC or 115 AC and store enough charge to produce a voltage of 450v to produce a flash
What is the stroboscopic effect
Can cause problems in some people (induce fits, epilepsy), makes moving or rotating objects appear stationary
What damage can be caused by strobe lights and what precautions should be done before commencing work on them
- Stroboscopic effect
- Eyesight damage: due to bright light
- Capacitance/heat: During maintenance make sure capacitors are discharged and heat dissipated before commencing work
What are the purpose of landing lights
They are installed on aircraft to supply sufficient illumination for the crew during the final stages of landing. They are mandatory
Typical places they are found: Wing leading edges, undercarriage legs and flap track fairings
What two types of landing light are there
Fixed: To the structure, do not alter when illuminated
Retractable: Can be deployed when needed
What sort of power would supply landing lights
28v AC or DC and power rating about 600watts. 115v AC is supplied through a transformer to give 28v DC
How much surge current can the transformers contacts take when transferring energy to the landing lights
15 times normal value
What is the purpose of taxi/turn off lights
To allow the pilot to manoeuvre the aircraft on the ground in the dark or poor visibility
What makes turn off lights different to taxi lights
They’re fitted on an angle instead of being straight on from the aircraft
What is the power rating of taxi lights
Normally lower than landing lights at around 250’watts the power supply is 28v AC or DC
What two filaments are installed on combined taxi/landing lights
400w taxi
1000w landing
What ensures the combined taxi/landing lights only operate when the gear is down and locked
The light switch circuit is via a contact in the landing gear handle
Why would an aircraft be fitted with a light illuminating the leading edge of the wings and sometimes the engine intake lip
They are known as ice inspection lights and provide sufficient illumination to see any ice build up
What is the power supply for ice inspection lights
28v AC or DC
Normally between 60w and 250w depending on requirements
What is the purpose of internal lighting
For the passengers to see, to enable crew to do their job effectively.
What is the purpose of instrument lighting
- To ensure the cockpit instruments are readable during all lighting conditions
- So no glare effects the instruments
What are the two types of instrument lights are there
- Integral lighting: An internal Part of the instrument
- Flood lighting: External to the instrument
What type of lighting system does the Central Warning Systems (CWS) have
A daytime setting brighter than night setting as in the day with ambient light it is harder to see
What does the storm lighting system do
When pressed it overrides all dim settings of any screens during a storm or bad weather to enable clear vision
What should be done to instruments lighting when the aircraft is being worked on
Turned to its dimmest setting to prevent heat build up
What type of power are cockpit warning and indication lights powered by
From the DC battery bus or from various DC sources to ensure effective working during system failures
What is used to test all of the cockpit lights are operational
A master test switch
It has 3 functions:
>Test - All warning and indicating lights are tested
>Bright - All lights to brightest function
>Dim - Illuminated with less intensity via a zener diode
What is the purpose of the Master Caution System
Indicates a fault on a particular system, installed at pilots eye level
What type of light is the cabin generally illuminated by
‘Wash lights’
What is the purpose of lights in cargo bays
To help during loading and maintenance activity
What will cargo bay lights be powered by
28v DC direct from aircraft battery
What is the purpose of emergency lighting
To assist passengers and staff in the state of emergency
They are required by law
What areas are illuminated by emergency lighting
- Cabin
- Exits
- Escape slides
- Illuminated escape paths
What are the 3 positions of the emergency lights
- Off: The system is de energised
- On: Lights are on steady
- Armed: Lights are off in normal aircraft operation and comes on in the event of a power failure
How is the emergency lights supplied if the DC supply fails
Their own emergency battery packs take over
What intensity must the emergency lights illuminate at and for how long when in active emergency mode
A minimum of 400 lamberts for at least 10 minutes
