Cargo and Service Compartment Lighting

Cargo and Service Lighting

• Purpose: to provide necessary illumination for cargo handling and service activities
• Types of lights used: dome lights, floodlights
• Power sources: internal power or external power source
• Switches: provided within the compartments the lighting serves

Flight Compartment Lighting

• Purpose: to provide illumination for the flight compartment, instruments, controls, and equipment
• Types of lights used: dome lights, lightshields, integral lighting for instruments and instrument panels
• Additional lighting: overhead floodlights for the control stand, floodlights for circuit breaker panels, lights for standby compass and map lighting

Altitude Alerting System (Boeing 767)

• System inhibition: altitude alerting is inhibited in flight whenever glideslope is captured or when landing flaps are selected with the gear down

Overspeed Warning System

• Purpose: to alert the flight crew if the airspeed exceeds the Vmo/Mmo limits calculated by the air data computer (ADC)
• Operation: sounds the siren or horn, illuminates the red master WARNING lights, and displays the message OVERSPEED on the EICAS upper display in red

Master Caution/Failure Panel (B737)

• Purpose: to receive inputs from various fault annunciators to illuminate two master caution lights and one of twelve sections of the master caution annunciators
• Function: "Push to Cancel", Push to Recall" function

Passenger Compartment Lighting

• Purpose: to provide illumination for the passenger compartment
• Types of lights used: ceiling and window lights, entry and threshold lights, lavatory lights, reading lights, passenger information signs, and attendant call system

Passenger Service Unit (PSU)

• Components: reading lights, Fasten Seat Belt & No Smoking signs, attendant call button, air conditioning fans, life vest storage, and oxygen mask storage

Passenger Reading Lights

• Operation: switched on or off using a touch-control button on a Passenger Panel
• Feature: 'Reading Reset' switch on the Attendant Panel to switch off all reading lights in one action
• Test: 'Read Lights Test' switch on a maintenance and test panel enables all reading lights to be switched on for inspection

Emergency Lighting

• Purpose: to provide illumination in emergency situations
• Operation: internal batteries are charged when 28V is on pin A (CHARGE and HOLD-OFF), and the lights turn on when voltage is removed from pin A and B
• Disarm: putting 28V on pin C (DISARM) to switch off the emergency lights

Self-Illuminating Signs

• Hazard: inhalation or absorption of gas released in the event of breakage of the glass envelope
• Precaution: handle carefully to avoid breakage, and evacuate the aircraft and open doors for ventilation if breakage occurs

Stall Warning System

• Purpose: to alert the flight crew of a stall condition
• Components: angle of attack sensing, stick-shaker motor, angle of attack indicator, aural warning, synthetic voice warning, and red master WARNING light
• Angle of Attack (AoA) sensing: measures the angle between the chord line of the wing and the direction of the relative airflow
• Critical AoA: varies depending on the aircraft design, typically between 12° and 18° for straight wings, and up to 30° or 40° for swept or delta wings