Aircraft Interior lighting
A great many types of aircraft lighting are determined by regulations for example, NVIS-friendly lights in military aircraft. It is the passenger cabin that allows the most scope for designer lighting.
Aircraft passenger cabin lighting
Some Passenger Information Signs are obligatory in FAA regulations, for example, fasten seat belt signs or no smoking signs. Interior Utility Lights illuminate cargo or freighter interiors. There is also, of course, Emergency Egress Lighting like floor track emergency lighting or emergency seat-mounted marker lights.
Aircraft Sidewall lights
Interior sidewall panelling systems for passenger aircraft increasingly incorporate large windows for passenger visibility, forward-facing indirect sidewall lighting wall wash lights, enhanced foot area lighting, cabin decompression ventilation, and a flexible, laterally overlapping panel connecting design. Sidewall panel designs have tended in the past to use direct lighting that radiates from above the sidewall and washes down along the panel, and also typically incorporate oval shaped windows. Since the overhead light washes down the panels in the conventional design, when the passengers look up, they are looking directly at the light source.
When the passengers’ windows are oval shaped and relatively small in area, they make it difficult for some passengers, e.g., those not situated immediately adjacent to a window, to see out of the aircraft easily without having to ctrane their necks.
The design challenge has been to produce aircraft interior panels that create a feeling of enhanced space and emphasise interior features by the use of lighting.
Lighting can now include a light source, such as an array of LEDs, whose light colour and intensity can be selected remotely, as well as a light bezel and a light lens. The bezel blocks the direct radiation of light into passenger’s eyes, and instead, directs it forward through the lens, so that the light washes forward.
Kick panels at floor level can also now provide location and mounting for one or more indirect lighting sources that are arranged to radiate light onto the cabin floor at the feet of the passengers, so they can see where to place their feet and easily find items stowed on the floor of the cabin beneath the seats.
LED Lighting solutions
Traditionally Fluorescent Lighting is energy efficient and much used. Also traditionally, Aircraft Passenger Reading Lights have been an integral part of passenger service units alongside the even distribution air “gaspers”. LED lighting is increasingly used for aircraft cabin lighting and has future prospects.
Passenger service units in an aircraft are equipped with a passenger interface and supply adapter. Each adapter includes an individual processor which is programmable independently of the aircraft central control.
LEDs for Aircraft Passenger Reading Lights are an adaptation of the Light-Emitting diodes (LEDs) that have been used in niche aircraft lighting applications, such as “No smoking” and “Fasten seatbelt” signs, for some time. Recent advances in white LED technology have prompted aircraft manufacturers to consider LEDs for more general cabin lighting applications, which could reduce onboard energy consumption.
Traditionally halogen, passenger reading lights have nonsymmetrical beam patterns, meaning that certain parts of the beam are brighter than others, rather than there being an even spread of light. LED systems tend to create a white beam surrounded by a blue ring. LED fixtures do however use half as much energy as the halogen fixture, offering lower replacement costs due to longer life.
LED lighting is clear, but arguably, too bright and too blue or green, creating unnatural skin tone colors.
Aircraft cockpit lighting
What could be more straightforward than aircraft cockpit illumination? Simple white light bulbs for map reading and other flightdeck chores. For years halogen lights have predominated in the cockpit. But now the older technology is beginning to give way to longer-lasting solid state LEDs.
Map and chart lights, table lights, utility, stowage and aisle lights, glareshield lights to floodlight the instrument panel, dome lights, floor lights, emergency lights and oxygen mask lights have all benefitted from more recent developments.
Cockpit mood lighting is rare at this time but studies have shown that tinted lighting in the cockpit by programming it to redden at dawn and dusk, simulating sunrise and sunset, can reduce pilot fatigue during long-haul flights. Cabin mood lighting has been so far been used in the passenger cabin.
Light-Emitting Diodes
New aircraft and retrofits use LEDs in the cockpit to increase reliability and reduce life-cycle cost. These solid state parts consume less power and have no coiled filaments, which can weaken from vibration and temperature extremes. Obsolescence is their Achilles heal. LEDs are solid state, semiconductor devices like a computer chip. Some suppliers offer only LED products, through-hole LEDs, or surface-mount LEDs.
Incandescent Lighting
Incandescent lighting is still about 90 percent of the cockpit lighting market. Incandescent lights, however, don’t last that long. Halogen lamps, using a similar incandescent technology, are replacing conventional bulbs. Of course a light’s life span depends on its circumstances and characteristics. Halogen is favoured for flight crew reading lights. Fluorescent lights last longer than incandescents.
NVIS-friendly lights for military applications
When the C-130 had a lighting retrofit a few years ago, by using the newest and brightest LEDs, several new dual-mode units met or exceeded the requirements of existing visible-only lights. The innovation these new units demonstrated were NVIS Friendly requirements and MIL-STD-3009, the latest lighting standard.