AIRCRAFT GALLEY SYSTEM

GALLEY SYSTEM

The galley units provide facilities for receiving, storing, preparing, and distributing food and beverages to passengers and crew.

The galley installation comprises storage compartments maker and a working area for the stewardess. The galley also houses a water tank, a drain valve, food as well as waste, hot cup coffee and a galley control panel. The water tank can be filled via the water service panel, located on the side of the fuselage. To check whether sufficient water has been put into the galley there is an over flow outlet on water service panel.

Galleys are the kitchen area of the aircraft. They are used to prepare food and drink for consumption during flight. The electrical power for the galley is supplied by the aircraft electrical system. Because of the high electrical current drawn to power all the galley services, they can normally be turned off by galley MAST switch situated in the flight deck.

 This master switch can be used by the pilot to ‘Off load’ the galleys during an electrical problem and so conserved the electrical power for the aircraft essential services. Some larger aircraft have a load shedding system, which is automatic in use, e.g. if an electrical generator fails, then the non-essential loads powered by the generator will be shed, this will include the galleys. For this reason part of the galley is fed from a different electrical power source to ensure that not all galley services will be lost though an electrical malfunction.

The small aircraft galley shown in Figure 3.2 is typical of the 40-60 seated aircraft. Meals prepared in trays are loaded into slots in the food tray containers. During take-off and landing the retaining bar is fitted over the doors to prevent accidental opening. As the meals are required, the trays are inserted into the heatable containers until they are heated to the required temperature and are than issued to the passengers.

A thermostatically controlled hot cup provides hot water for beverages. It is filled from a water tank installed directly above it. The hot cup can be filled without removing it from its shelf by turning the water tank valve on the water tank.

Galley waste is placed into a disposable bag via a hinged cover on the work surface of the galley. The bag is removed after each flight through the waste bag access panel and a clean bag refitted ready for future use.

All the control switches, with exception of the galley master switch, are placed on the galley, including the thermal circuit breakers, which are connected with the hot cup and heatable container protection circuits.

The illustration in Figure 3.3 show a galley fitted to a large public transport aircraft.

Meals on trays are stored in the carts and transferred to the ovens as required. The hot meals are taken from the ovens and placed in the carts to be pushed down the aisles to serve the passengers. The ovens on the galley illustrated can cook up to approximately 300 meals at once; the carts can each carry 56 meal trays.

The ovens are control by a switch panel in the galley area. Storage cupboards and spare carts contain all other requirements for the cabin crew to serve the passengers such as:

(i)                 Minerals

(ii)               Cigarettes

(iii)             Alcoholic drinks

(iv)             Cups and glasses

(v)               Napkins and spare cutlery

On wide bodied business jet airliner, there are several galley units in each compartment. On typical aircraft, there are six galley units installed in the passenger compartment, two in the forward end, two inboard of the mid passenger doors, and two in the extreme aft portion of the compartment. The forward units are identified as the G2 and G3 galleys. A miscellaneous stowage area is provided forward of the left forward passenger door in lieu of a G1 galley unit. The G2 galley is installed forward of the right forward passenger door. The G3 galley is installed across the aircraft centreline inboard and just aft of the forward doors. The mid units, identified as the G4 and G5 galleys, face each other across the aircraft centreline inboard of the mid passenger doors. The aft units, identified as the G6 and G7 galleys, face each other from left and right sides of the aircraft centreline inboard and just aft of the aft passenger doors. This aircraft is also provided with provisions for a crew rest area on the left forward side of the passenger compartment between the lavatory and flight compartment.

Galley system has some maintenance problems due to spillage of fluids that causes corrosion. Periodic inspection for signs of corrosion in the fluid entrapped spaces is performed. Another problem is the burns due to overheat. Special care is to be exercised. Fuses and CBs are to be replaced whenever required for circuit protection in the electrical heater systems.

CABIN ENTERTAINMENT EQUIPMENT

CABIN ENTERTAINMENT EQUIPMENT

 The passenger entertainment system is a vital system of a large modern airliner. It is one of the most complex system in the aircraft. It is also the system that causes most trouble. Fortunately, it is least likely to affect the safety of the aircraft unless bad servicing leads to a fire or loose-article hazard. Even on the same type of aircraft, a variety of services will be available since different operators will offer different entertainment in a bid to capture more customers. In view of the above comments, the following description is particularly brief avoiding complexity involved.

 Public address system: The PA system comprises PA amplifier, tape deck, annunciator panel, attendant’s panel, PA accessory box, control assemblies, speaker switch panel and loudspeakers. The various PA messages have an order of priority assigned to them: (i) Pilot’s announcements, (ii) Attendant’s announcements, (iii) Pre-recorded announcements and finally (iv) Boarding music. All PA audio is broadcast over the speaker system and also, except for boarding music, overrides entertainment audio fed to the passenger stethoscope headsets. A pre-recorded emergency announcement may be initiated by the pilot or an attendant, or automatically in the event of cabin decompression. A chime is generated when the pilot turns on ‘fasten seat-belt’ or ‘no smoking’ signs.

 Films, video, television & audio system

Films: The passenger entertainment video system provides pre-recorded video programs via projector or CRT display or LCD display through out the passenger compartments. After amplification, the audio for the video programs is connected through the music system junction boxes for distribution over the loudspeakers via the entertainment music system and/or individual passenger seat control units.

Pre-recorded programs, stored in the video tape cassettes, are switched through the system control unit. The recorded picture are projected or displayed onto the screen in each viewing zone. The recorded films configuration differs by the system installed in the aircraft. Normally the film is high density 0.5” (inch) width Beta cassette tape, with two magnetic audio sound tracks, for dual language or stereo programming, is used to provide up to 180 min. of pre-recorded video entertainment.

Video: 

The Video Tape Reproducer (VTR) is a compact, light weight, front loading cassette reproducer with dual channel audio output. The unit is capable of reproducing PAL, SECAM, NTSC. Normally on the front faces of the VTR available features are: REW (rewind), PLAY, FF (fast forward), STOP and EJECT button.  Besides these STANDBY/ON, CASSETTE INSIDE, video signal format indicator, mode selector, elapsed time indicator, tracking adjustment control knob, cassette access door etc. are available. 

Television: In projector type video system, three-gun projector is mounted in a specially strengthened and modified container in the centre hat rack channel in each viewing zone. Three mono-chromatic cathode ray tubes (red, green and blue) and acrylic lenses are used to project video images on to the screen.  In television type monitor, the monitor receives the video signal from the system control unit. The video picture is visible on the video monitor screen. Maintenance adjustments for vertical hold, colour, hue, bright and picture are in front of the video monitor.  In LCD type display, the LCD monitor shows the video program on Liquid Crystal Display (LCD). The LCD monitor provides an individual power ON/OFF switch. A maintenance load switches ON/OFF to switch the 50 ohm termination ON/OFF is on the top of the LCD monitor.

Audio System: Audio system in the aircraft is a part of the passenger entertainment system. Music system i.e. audio system provides pre-recorded audio entertainment programs for the aircraft passengers. Programs can be individually selected and heard over a headset connected to the passenger control unit in seat armrest. In addition the system provides boarding music.

The systems uses an audio tape reproducer and a power amplifier to provide stereo and mono channels of audio entertainment to the PCU’s in the seat armrest and in addition, one channel of the boarding music fed from the tape reproducer to the PA amplifier. The audio signals are distributed through under floor cables via the Audio Junction Boxes (AJB) to the Floor Disconnect Boxes (FDB) in the cabin floor. The channel arrangement in the AJB in relation to the PCU channel selector to be pre-set.  The audio entertainment channels can be individually selected at the seat PCU’s and heard through headsets. Volume control can also be made at the PCU. Provision has also been made for selecting video channels of video program sound at the PCU’s and listening to the program over the headsets. The components of audio systems are Tape reproducer, Power amplifier, Attendant control unit and passenger control unit.

TYPICAL CABIN LAYOUT

Typical Cabin Layout

Figure 3.1 illustrates a layout for a passenger aircraft showing the provisions and their arrangement in a typical aircraft.

Look at the arrangement and location of:

(i)                 Passenger seats

(ii)               Galleys

(iii)             Toilets

(iv)             Partitions/ temporary bulkheads

(v)               Access doors

(vi)              Emergency exits

(vii)           Doors for passenger loading (forward, left door)

CABIN ARRANGEMENT AND EMERGENCY EQUIPMENT

Cabin arrangement

Cabin is arranged with different provisions for most convenient way of passenger comfort, entertainment and catering. Seats arranged in gang with rows giving single to two aisles. There are oxygen systems, air circulation system, passenger control unit (PCU) with multiplexer encoder, lights, cabin attendant calling system with cabling. Other provisions in the arrangement includes:  tables and cabinets, aisle lights, accessories (seat belt, ashtray etc), galleys, toilets, emergency evacuation systems and equipments, partitions, hat rack, coat room and so on.  

This week highlights different provisions in the cabin.

PASSENGER SEATS AND CABIN ARRANGEMENTS

PASSENGER SEATS AND CABIN ARRANGEMENTS

Passenger seats are attached to seat tracks in the cabin floor and may be arranged for different passenger configurations by moving the seats forward or aft on the seat tracks. The seat tracks consist of beams of special cross section and are bolted to the floor structure. The seat tracks are provided with circular cutouts for the seat studs and lock pins to be fitted into.

Passenger seats can be anything from single to quadruple and for some wide body aircraft nine seats abreast in arrangement and contains within the back of the seat facilities for table attachment and literature pockets. Some means of luggage restraint is under the seat for “carry-on” luggage to prevent this luggage moving about the cabin floor when positive or negative “G” loads are experienced. 

Arm resets are provided for comfort. However, included in the design are ashtrays, in-flight entertainment channel selectors, and in some cases, chime calls for flight attendants. Depending upon the type of configuration of the aircraft seating arrangement, seat angle adjustment facilities mat be included.

In a typical aircraft, passenger seats are arranged nine abreast in the first-class area (except for the first two rows and last row) with a row of quintuple-seat units down the centre, an aisle on both sides, and a row of double-seat units outboard of each aisle. The first two rows of centre seats are quadruple-seat units. There are no centre seats in the last row of first class seats. Passenger seats in the economy area are installed nine abreast with a row of double-seat units outboard of each aisle and extend from the mid lavatories "C" and "D" to the aft passenger doors.

Quintuple seats are installed across the aircraft centreline and extend from the G5 galley unit aft to the third row of triple seats forward of lavatories "E" and "F", with breaks for stowage facilities.

Identification: Passenger seat units are identified as first class and coach, with variations incorporated due to location within the aircraft. First-class seats are double, triple, and quadruple units. Each quintuple seat arrangement consists of a double and triple seat unit. The first class double-seat units are equipped for right, left, centre-left and centre-right installation. The triple and quadruple seats are equipped for centre installation only.

Coach seats are double, triple, and quadruple units. Each quintuple seat arrangement consists of a double and a triple seat unit. The coach double-seat units are equipped for right, left, centre-left, and centre-right installation. The triple and quadruple seats are equipped for centre installation only.

Attachment: Passenger seats are attached to floor-mounted tracks and can be positioned in the fore-and-aft direction in 1-inch increments. Studs in the aft and forward legs secure the seat unit to the track. A shear locking pin mechanism is installed in the vicinity of the aft leg. The lock mechanism operates with a positive snap action to place and retain the lock in the locked and the unlocked positions.

The lock mechanism allows the seat to be installed or removed from the aircraft without the use of tools. The aisle face of both leg shrouds is marked with a line of contrasting colour to enable the centreline of the seat track locking pin to be easily determined.

Interchange ability: All seat units of any configuration are interchangeable to right, left, or centre mounting. Each unit has complete provisions for special aisle requirements, such as aisle lights and hostess call lights.

Backrest: Each passenger seat is equipped with an adjustable backrest containing a backrest cushion and provisions for stowage, restraints, wire and cable routing, and equipment installation as required. The backrest of coach seats can be adjusted to positive stops at 21 degrees, 30 degrees, and 34 degrees from the vertical in a typical aircraft. In this aircraft, first-class seat backrests can be adjusted to positive stops at 21 degrees, 34 degrees, and 38 degrees from the vertical. The backrest incorporates means to counterbalance its own weight and to add sufficient force to move the backrest forward from any recline position when the recline lock control button on the armrest is depressed. The backrest houses an environmental control compartment containing a passenger oxygen system, a circulating air system, and related wiring. The compartment is closed by a hinged cover, spring-loaded to the open position. The cover is secured by a solenoid-operated latch, activated by a remote aneroid sensor when ambient cabin pressure fails to a preset level.

Flight Observer's Seat (First/second observer)

(1) The absence of a power unit and related mechanism is the major difference between the observer's seat and the captain’s/first officer’s/flight engineer’s seat. These seats are manually operated in the vertical and fore-and-aft directions. In a typical aircraft, first observer’s seat is an adjustable, non-folding seat where fail-safe position locks are installed. Where as the second observer's seat is a folding nonadjustable type, bolted directly to the floor substructure and positioned next to the aft partition adjacent to the flight compartment Entry. See Figure 2.2.

(2) Neutral Position: The neutral or normal position for the first observer's seat is an attitude facing the captain's station with the aft portion of the bottom seat cushion 25-5/16 inches above the floor. In this position, the centreline of the seat is approximately 18 degrees clockwise to a line parallel with the airplane centreline. From this position, the seat can be moved a total of 5 inches in the fore-and-aft direction and can be raised 2-1/2 inches, lowered 8-5/16 inches and rotated clockwise (inboard) 72 degrees. Controls for movement of the seat are located on the inboard side of the seat pan. A compression spring provides energy for assist in lifting, and the occupant's weight is utilized to lower the seat. To lower the seat, the occupant sits in the seat and releases the control lever, and the seat lowers slowly. To raise the seat, the occupant rises and pulls upward on the seat with a small force (approximately 5 pounds).

(3) Fore-and-Aft Movement: The fore-and-aft control is immediately aft of the vertical control. Movement is accomplished by the occupant lifting the fore-and-aft control handle and then manually moving the seat in the desired direction.

(4) Backrest and Swivel: The backrest is fixed and cannot be adjusted. The back cushion is an individual flotation unit and is removed by lifting it out of the seat. Swivel of the first observer's seat affords the in-flight crew entry to the avionics compartment through an access door in the flight compartment floor.

(5) Footrest: A footrest is attached to the forward-lower portion of the seat pan support structure. The footrest is folded in toward the seat to a stowed position aft of the forward edge of the seat pan prior to rotating the seat.

(6) Armrests: The armrests are adjustable by a release and lockup control located under the forward edge of each armrest. Both armrests can be pivoted to a stowed position parallel with the backrest.

(7) Cushions and Covers: The back cushion is an individual flotation unit and is removed by lifting it out of the seat. The backrest and bottom covers can be removed for repair or replacement.

(8) Shoulder Harness: A fully automatic inertia reel and dual shoulder harness are provided for the first and/ second observer. A lap-belt assembly with a metal-to-metal buckle accommodating the ends of the shoulder harness is provided. The lap belts are equipped with retractors.

Figure 2.6: Typical cabin attendant’s seat

2.5.3 Cabin Crew/Flight attendant’s Seats: There are a number of seats in addition to 

 

passenger seats, which are located through out the cabin compartment for use by cabin staff during landing and takeoff. These seats are normally the folded module type, which fold away after use, thus allowing more space in the cabin area.

The seat bottoms are normally cushioned and attached with quick attach-detach pins to allow the seat bottom to become an individual flotation device in the event of the aircraft ditching in the sea. Attached to the seat assembly is a seat harness for use by the seat occupant.  See Figure 2.6.

CREW SEATS

CREW SEATS

Seats for the captain, first officer and flight engineer are power operated to provide vertical and horizontal adjustment. This adjustment is accomplished by the occupant using a single control handle. A separate control is used to adjust the seat back to the desired recline position. The first observer’s seat is manually adjusted and can be swivelled to face inboard. The second observer’s seat is not adjustable and does not swivel. Each seat is equipped with a retractable shoulder harness and adjustable seat belt. The second observer’s seat contains provisions for stowing a life vest below the seat bottom. All other seats in the flight compartment have life vest stowage provisions in the seat back.

Flight Crew Seats: Flight compartment is furnished with seats for captain, first observer, flight engineer (if any) and the observers. There are consoles of the captain, first officer and observers (first, second observers, 3^rd occupants as per design). Typical layout of flight compartment is shown in Figure 2.1, 2.2, 2.3

(i) Captain’s/first officer’s/Flight Engineer’s seats: These seats are cushioned, upholstered-type, mounted on pedestals, and adjustable in a vertical, fore- and aft and lateral (inboard-outboard) direction (Figure 2.4). The upholstery is flame resistant material, removable for repair or replacement. Each seat is power operated and incorporates all direction of motion within the seat. The seats are left and right units. Both seats have all controls on the inboard side.

Backrest: Each seat is equipped with an upholstered backrest, a bottom cushion, and armrests. The seatback cushion is an individual flotation unit and is removed by lifting it out of the seat. The backrest is adjustable and contains provisions for a headrest. A positive type lock-and-release control, located on the inboard side of each seat pan, releases the back for recline adjustment. In a typical design, the backrest in the normal position is 7 degrees aft of vertical, and the full recline position is 27 degrees from the upright position.

Thigh Support: Approximately the forward half of each seat bottom is capable of being tilted upward to provide thigh support for the occupant. Adjustment is made by releasing a control lever located at the top of the seat pan on the inboard side and pulling up on the forward edge of the seat until the desired angle is reached. To lower, the control lever is released and the seat front is pushed down.

Armrests: The upholstered armrests are moulded, integrally padded units. The outboard armrest incorporates vertical rotation adjustment (angular sweep about the pivot point). Release and lockup are affected by a finger-tip control located under the forward edge of the armrest. Each armrest can be pivoted and rotated to a stowed position behind the seatback. The armrests can be removed for repair or replacement.

Seat Belts and Shoulder Harness: Each seat is equipped with seat belts, adjustable notch straps, and a shoulder harness with inertia reel. The seat belts are adjustable and equipped with a rotary-type, quick-release buckle. The shoulder harness is attached to the inertia reel located in the seatback. The inertia reel permits the occupant to move forward as desired and take up the slack when the occupant moves back. When sudden excessive loads are exerted on the harness, the reels lock automatically, preventing the occupant from moving forward.

Lumbar Support: A lumbar support is installed on each seat for the captain, first officer and flight engineer. The unit provides a mechanical means of adjusting the seat back cushion around the occupant's torso at the small of the back and sides for support of the kidney area. The unit is hand-operated and positive positioning is provided through a spring-loaded latch seating in the grooves of a serrated plate. The mechanical lumbar support is not required on a seat with a back cushion incorporating a pneumatic lumbar support.

FIRE RESISTANCE REQUIREMENTS

FIRE RESISTANCE REQUIREMENTS

In the pursuit of aesthetic cabin furnishings, aircraft manufacturers and operators must consider one major and important factor when choosing upholstery materials. The must be fire proof and the materials must be prevented from emitting toxic gases. Recent experiments have shown that incapacitation of passengers has resulted from inhalation of toxic gases rather than post crash impact.

Most seat squabs and back supports are manufactured from foam type materials. When heat is applied to this material, cyanide gas is produced during the burning of the material. As means of slowing down this action the seats internal parts are covered with a fire blocking material, which is designed to prevent the foam from burning and consequently allow the occupants a better chance of vacating the aircraft in the event of a cabin fire. 

Because of the problem of smoke and the inability of passengers to see in smoke conditions, legislation is made to use some means of an exit indicating system that is close to the floor level. This legislation is applicable to all transport (passenger) aircraft over 5700kg MTWA for which a type certificate was issued after 1^st January 1958.

How the emergency escape path lighting will be achieved has to be decided by the aircraft operators or manufacturers. The most popular method is to include small aisle lights. which will illuminate under certain conditions.

The height of the escape path lighting system must not be greater than 4ft. The escape path system is designed to indicate to passengers the direction in which to go in the event smoke conditions, and at the same time indicate the areas that contains the emergency exits. 

Escape path lights will be white; red lights will be used to indicate the emergency exit doors.

Although fire-blocking materials are to be used in seat upholstery, the actual covers are also treated with a fire resistant substance. One important point to consider however that is the fire resistant qualities are gradually reduced when the seat covers are dry-cleaned. In most cases, manufacturers indicate the maximum number of times that the covers may be dry-cleaned before the fire resistant treatment has to be reapplied. The number of dry-cleans will depend only upon the manufacturers recommendations.

PARTICLE BOARDS AND PLASTIC LAMINATES

Particleboards and plastic laminates are used as partition wall and toilet wall. They are non -structural members. Decorative sheets are laminated to the board for interior decoration. The particleboards are made of sawdust, jute stick etc. The plastic laminates are prepared out of plastic materials.

CARPETS AND CURTAINS

 CARPETS AND CURTAINS

  Carpets: In most homes carpets make an attractive decoration to the room. The same can be said for an aircraft cabin. The sight of a carpet tends to relax passengers and make them feel at home. However, aircraft carpets serve two functions. They:

a)     Make the cabin environment more attractive and pleasing to the eye.

b)     Act as a sound proofing material on the floor and in some cases on the sidewall panels.

Carpets must be made of fire resistant materials, and also should be non-toxic when subjected to heat. The padding on the under side of the carpet is specifically for the soundproofing of the cabin area. Carpet edge and ends are retained by double backed tape. In some cases, especially where the carpets are subjected to heavy use, Velcro tape may be used. Where carpets are fitted next to seat tracks, extruded plastic seat track covers are snapped into seat tracks between the seats.

2.2.2 Curtains: The use of curtains is fairly limited in passenger cabin areas. Normally they will be fitted at galley partitions to close-off the galley once the meal preparation has been completed. They may also be used to shut-off cabin staff areas from the passenger area. If curtains are fitted they must be of fire resistant woolen material.