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A typical airliner lavatory

An aircraft lavatory is a small room on an aircraft with a toilet and sink.

Historical aircraft toilets[edit]

During World War 2, large bomber aircraft, such as the American Boeing B-17 Flying Fortress and the British Avro Lancaster, carried chemical toilets; in British use, they were called Elsans after the company that manufactured them. These often overflowed and were difficult to use. The intense cold of high altitude required crews to wear many layers of heavy clothing, and the pilot might have had had to take violent evasive action with little warning. They were unpopular with bomber crews, who would avoid using them if at all possible.^[1] Bomber crew members sometimes preferred to urinate into bottles or defecate into cardboard boxes, which were then thrown from the aircraft.^[1]

The British Supermarine Stranraer flying boat was fitted with a toilet that was open to the air. When the lid was lifted in flight, airflow produced a whistling noise that led to the aircraft being nickamed the Whistling Shithouse.^[2] The Short Sunderland flying boat was comparatively well equipped, carrying a porcelain flush-toilet.

Smaller aircraft such as fighters were fitted with devices known as relief tubes. These consisted of a funnel attached to a hose that led to the outside and which could be used for urination. These devices were awkward to use and could become frozen and blocked in the intense cold of high altitude.^[1]

Such devices are still sometimes fitted to modern military aircraft and small, private aircraft although they are difficult for women to use. Male glider pilots undertaking extended soaring flights may wear an external catheter that either drains into a collection bag or is connected to tubing that dumps the urine to the outside. If the latter approach is used, care must be taken when designing the system so that the stream of urine does not make contact with other parts of the aircraft, where it may eventually cause corrosion.^[3]

Current minimum standards[edit]

Lavatories per passenger provided aboard aircraft vary considerably from airline to airline and aircraft to aircraft. On board North American aircraft, including low-cost, charter, and scheduled service airline carriers, the normally accepted minimum ratio of lavatories to passengers is approximately one lavatory for every 50 passengers. However, in premium cabin and business cabins, passengers may have access to multiple lavatories reserved primarily for their use. These ratios of lavatories to passengers vary considerably, depending upon which airline is being used with some first class passengers having one lavatory for every 12 passengers. Additionally, many of the larger long-haul airlines elect to equip their aircraft with larger lavatories for this particular group of passengers willing to pay higher fares.

Smaller commuter aircraft and regional aircraft designed for short-haul flights may not be equipped with lavatories. Recently, many regional airlines in North America have commenced the trend of eliminating the refilling of hand-washing basin potable water tanks in order to reduce weight and reduce labor service costs, thus generating increased airline profits derived through added fuel savings due to reduction of aircraft weight and employee labor expenses.^{[citation needed]} To facilitate sanitation, disinfectant hand-wipes are provided.

Fixtures[edit]

First Class Lavatory with a Window (Air Canada)

• Ashtray
• Built in waterless toilets with push button flush
• Call button - for assistance
• Electrical outlet
• Garbage can - small push door to discourage use of toilet to dispose of non-human waste items
• Handle bars to assist elderly or disabled passengers to get up from toilet
• Handwash faucet and sink (i.e., taps or push button)
• Mirror
• Paper towels
• Soap dispenser
• Toilet paper dispenser or linens
• Paper cup dispenser
• Sign on door to indicate lavatory in use or not in use
• Toiletries - handcream, facial tissue, sanitary napkins

Fitted cabinets may contain additional toilet paper and other toiletries, but they are often locked. The toilet and sink are often moulded plastic or a stainless steel sink, the floor is usually a non-slip surface. In newer aircraft, the executive or first class lavatories are roomier and offer more toiletries and other comforts.

The presence of an ashtray is sometimes commented upon, given that smoking has been long banned on flights in many parts of the world. However it is a requirement of the Federal Aviation Administration that ashtrays continue to be fitted to the doors of aircraft toilets. This is due to the fire risk caused by the possible disposal of illicitly consumed smoking materials in the toilet's waste–bin.^[4] In 2011, a Jazz flight from Fredericton, Canada to Toronto was prevented from taking off because an ashtray was missing – the aircraft instead flew to Halifax without passengers to have a new ashtray fitted.^[5]

Waste bins are fitted with halon fire–extinguishing bottles and "oxygen-smothering" "flapper lids", and the toilets equipped with smoke detectors. Over time these protective devices have been incorporated into aircraft lavatory designs due to fires that have started when the careless smoker of the past or the clandestine smoker of the present has incorrectly disposed of smouldering smoking material. If the toilet's fire extinguishing system is inoperative, the aircraft is still permitted to fly, provided the toilet is barred to passengers and only used by crew members.^[6]

Types of aircraft lavatories[edit]

An airplane lavatory viewed from the outside

Lavatories on modern aircraft are very expensive, and include features that have required substantial upfront and long term investments by the world's airlines to design and develop. Airlines and aircraft manufacturers continue to investigate ways to improve lavatory design technology to increase functionality and reduce costs of production, while maintaining adequate levels of safety, hygiene and amenity.

For this reason many modern lavatories are now no longer of the "chemical toilet blue water recirculated electric flush" variety. Instead lavatory manufacturers have progressed to "vacuum flush" technology to eliminate solid and liquid residue from the basin, patented in 1975.^[7]

Some of the advantages of "vacuum flush technology" systems, from aircraft designers’ perspective, is the increased safety attributes through less risk of corrosive waste "spill over" into recesses around the lavatories which can be difficult to protect. Additionally, "vacuum flush systems" are considered to be less odor-inducing and substantially lighter which bear substantial fuel savings by way of reducing the need to carry excessive "blue recirculating water" as in the past.

Lavatory agents[edit]

The toilets of a McDonnell Douglas MD-80 being serviced

Each aircraft equipped with a bathroom or lavatory needs to expend its waste somehow. This is where the lavatory or "lav" agent comes in. After an inbound aircraft arrives it is the lav agent's job to flush the lavatory system. In stations with higher volumes of passenger traffic, lavatory agents will usually utilize trucks adapted with large tanks on board that do not need to be emptied as often. These are also configured to facilitate access to the waste ports of the aircraft, which can be out of reach by other means. In places where fewer or smaller aircraft are being serviced a "lav cart" (essentially a small lav truck pulled behind a tug) is used to service the lavatories.

See also[edit]

Aviation portal

• "Mile High Club"
• Board toilet
• Space toilet

References[edit]

External links[edit]

Wikimedia Commons has media related to: Aircraft toilets

• A typical aircraft Vacuum Toilet System, as used on Boeing B737-600/B747-400/B757-200/B767-300 and B777-200