204: Aviation Life Support System (ALSS) Utilities System

204.1.1 State the purpose of the following utility systems:

a. Air Conditioning- the air-conditioning system uses an air cycle refrigeration unit and supplies bleed air to provide heating and cooling. The solenoid operated environmental control system bleed air shutoff valve controls the flow of bleed air to the air cycle refrigeration unit. The ECS valve is opened and closed by a switch on the TEMP CONTROL panel. Feathering either propeller closes the valve automatically, preventing a power loss of approximately 600 ihp on the operation engine. The valve is also automatically closed during engine start. If the ECS valve has closed because of the propeller feather, it can be reopened from the TEMP CONTROL panel.

b. Cabin Pressurization: The cabin pressurization system automatically maintains air pressure in the cabin. Pressurization starts at an altitude of 4,000 feet and is maintained at 4,000 foot cabin altitude until pressure differential of 6.5 psi exists between cabin and atmosphere pressure. The 6.5-psi differential occurs at approximately 22,000-foot altitude at a constant differential of 6.5 psi.

c. Liquid Oxygen: The liquid oxygen system converts liquid oxygen to gaseous oxygen for use by the pilot, copilot, and passengers.

d. Passenger Oxygen: Each passenger service unit contains two masks behind a door that unlatches and opens when system pressure is applied, allowing the masks to drop out. By pulling the mask toward him for use, the passenger pulls an attached lanyard that extracts a pin, opening the mask valve and allowing oxygen to flow to the mask. When the door is open, a supplemental oxygen lever marked SUP is accessible. Flipping this lever down provides a supplemental flow of 70 to 90 percent more than a single outlet and is available at the mask connected to the tee.

e. Walkaround Oxygen Bottle: A low-pressure emergency portable walkaround bottle with diluter demand regulator is stowed in the cargo compartment port side at fuselage station 500.5. With the regulator set to 100 percent oxygen and with the user experiencing little or no physical exertion, approximately 20 minutes of oxygen is available. Tasks requiring moderate exertion will reduce use time to approximately 5 to 10 minutes. Under conditions requiring pressure breathing, use time is significantly reduced.

f. Side Window Defogging: Side window defogging control is a thumbwheel control on the De-fog portion of the ANTI-ICING, DE-ICING, DE-FOG panel with an arrow marking the direction of INCREASE FLOW. The thumbwheel has positions marked OFF and 1 to 7. Setting the control to OFF secures airflow to the defogging diffusers. Rotating the thumbwheel toward 7 increases airflow. If air is secured because of over temperature, turning the thumbwheel to OFF, then toward 7 may restore it.

g. Windshield Anti-icing: The windshield anti icing system consists of two dual temperature controllers that direct 115 vac, 400 Hz, three phase power to two heating bus bars embedded in each front and side windshield. Sensing elements within each windshield and side panel controls the heat generated by the bus bars. The system is energized with the cockpit windshield anti icing switch on the overhead console. When energized, the system prevents ice formation on windshields and side panels by heating and maintaining them to 32.2 degrees C. (90 degrees F)

h. Wing and Tail Deicing: The wing and tail system uses pulsating rubber boots to eliminate ice formation. The boots are bonded to the leading edges of the wings, stabilizer, and fins. A timer, energized by the wing tail deicing switch in the cockpit, controls three distributor valves, energizing them in sequence to apply air pressure (18 psi) and then suction (6 inches Hg) to the deicer boots. The engine bleed air through a pressure regulator and relief valve supplies air pressure, and suction is supplied from an ejector and regulated by a relief valve.

i. Engine Fire Extinguishing: Two independent, electrically actuated, high rate of discharge fire extinguishing systems combat fires in the engine nacelles. Each system consists of an extinguishing agent (bromotrifluoromethane) container, emergency cutoff handle, fire extinguisher switch, and the necessary tubing to route the agent to the fire.

204.1.2 State the location and purpose of the aircraft portable fire extinguishers: * There are two portable fire extinguishers: one mounted on the back of the pilot seat and one in the aft cabin. They are charged with approximately 2 pounds of monobromotrifluoromethane vaporizing liquid and are nonrefillable. Instructions for use are on a decal on the extinguisher. For us in an emergency.

204.1.3 Explain the proper operation of the cockpit and passenger seat adjustment handles:

Cockpit seats the normal reclining range is from 8 degrees to 18 degrees. It is controlled with a recline handle at the rear of the seat base. An extra recline adjustment of 29 degrees can be obtained when the seat is in the sixth hole forward of the aft stop. Fore and Aft adjustment made through a range of 10 inches is provided with a fore and aft handle directly below the recline handle. Fore and aft adjustment is automatically located out when the seat is in the 29 degree recline position. Vertical adjustment A 4 inch vertical adjustment is available by positioning the two-position vertical adjust (VERT ADJ) handle on the forward right side of the seat bucket. Pulling the handle up the UNLOCK initiates the adjust operation. Pushing the handle down to LOCK prevents the seat form the selected height. Passenger seats Can be tilted back 16 degrees from the normal position, in two increments of 4 degrees and one increment of 8 degrees. The seat adjustment lever on the outboard side of each seat permits the seat back to be adjusted to five individual positions. Moving the lever upward toward the stop position, the seat may be positioned to any one of four reclining positions. When the seat is being stowed, a lockpin above the seat-adjusting lever is depressed to permit the lever to be moved to the full up position. This permits the seat back to be pushed full down to the stowed position.

204.1.4 Discuss the purpose and location of the underwater acoustic beacon: * The beacon emits pulses of sound at one pulse per second after being actuated by immersion in either fresh or salt water. Design life of the beacon is 30 days. It is located on the CSFIR box between AHRS (ECU) No. 1 and the GPS Box overhead aft of cockpit.

204.1.5 State which installed components fall under the Conventional Ordnance Handlers Certification Program: CADS, Pyrotechnics, and smoke flares.

204.1.6 Discuss the sequence of events after manual operation of the NB-8 parachute:

a. Manually pulling the ripcord handle removes the ripcord pins form the container locking cones, permitting grommets and locking cones to separate. b. The container spring opening assemblies pull the side flaps apart allowing the pilot parachute to spring from the container and inflate. c. The aircrewmember falling away from the inflated pilot parachute causes the canopy to be extracted from the container followed by the suspension lines. The canopy begins to inflate during this operation. d. The connector link tacking breaks as load is applied. The risers are then pulled from the container, the canopy inflates. This permits the aircrewmember to descend suspended in the harness. e. By manually actuation the four line release system the aircrewmember may reduce oscillation and maneuver parachute to a less hazardous landing site. f. Upon landing, the aircrewmember releases the canopy by actuation of the harness quick fit ejector snaps.

204.1.7 State the items contained within the Standard Soft Pack (SSP) equipment container:
(2) Dye Markers
(2) Distress Signal, MK-13 MOD 0 or Distress Signal, MK-124 MOD 0
(1) Emergency Radio Beacon
(1) Battery Power Supply
(2) Water, Drinking, Bagged, Emergency
(1) Opener, Can, Hand
(1) Cord, Nylon, Utility 50 ft
(1) SRU-31/P Individual Survival Kit
(Part 1 Medical, Part 2 General)
(1) Ground Air Emergency Code Manual
(1) Combat Casualty Blanket type II, 3 oz.
(1) Bailing sponge
(1) Personnel Lowering Device (optional)

204.1.8 Discuss the protective features provided by the Mask Breathing Unit (MBU) series oxygen mask:

* Pressure demand type masks used in conjunction with the lightweight helmet assemblies used aboard fixed wing aircraft. The oxygen mask are designed to be worn overt the face, forming a seal to the cheeks over the bridge of the nose and under the chin. The mask is designed for use with a regulator which provides breathing gas (100% oxygen or oxygen diluted with air) upon demand at a pressure schedule dependent on the altitude. The mask can also be used with continuous flow bailout or walkaround oxygen source. The mask provides facial protection form projectiles and fire as well as being qualified for depths of 16 feet under water. A properly fitted oxygen mask is essential to helmet retention in high speed ejections. The face piece permits utilization of the valsalva maneuver to equalize pressure in the middle ear during descent.

204.1.9 Explain the air/water temperature requirements for mandatory wearing of anti-exposure assemblies:

a. Water temperature is 50 degrees F or below.
b. Outside air temperature is 32 degrees F (wind chill factor corrected) or below.

204.1.10 State the minimum buoyancy in pounds provided by the LRU-21 life preserver: * The minimum buoyancy is 65 pounds

204.1.11 State the items contained within the LRU-13A liferaft and the number of survivors it can hold:

(3) Desalter Kit, sea water, MK2, Type II
(4) Sea Dye Marker
(5) Distress Signal, MK-13 MOD 0 or Distress Signal, MK-124 MOD 0
(2) Water Storage Bag (size A)
(18)(7) Water, Drinking, Bagged, Emergency
(1) First Aid Kit, Size A
(1) Opener, Can, Hand
(1) Desalinator, manual Reverse Osmosis
(1) Sunburn Preventative Cream (8) or Sunburn Preventative Preparation
(7) Food Packet
(1) Bailing Sponge
(1) Hand pump
(1) Combat Casualty Blanket Type I
(1) Hand Generated Flashlight A-9
Packet in Supply Pocket:
(1) Flare Gun, MK-79 MOD
(1) Signal light (strobe) SDU-5/E
(2) Light, ChemiLuminescent
(1) Signal Mirror, Type I or Signal Mirror, Type II
(as required) Survival Radio and or Radio Beacon AN/URT-33A
(1) Battery
(1) Code Card
(1) Whistle, Type II
(1) Compass, Pocket, Type MC-1 or Compass, Wrist
(1) Pocket knife
(1) Cord, Nylon, Utility, and 50 feet.
( 7 man life raft)

204.5.1 State the special safety precautions as they apply to LOX system handling/servicing:

a. Never store or handle liquid oxygen in a poorly ventilated area or close to flammable materials. When splashed with liquid oxygen, organic materials such as clothing, cigarettes, and oils burn violently if ignited within several minutes after exposure. Flames, sparks, burners, heaters, and exhausts must be kept away from storage vessels, portable units, and the aircraft, when liquid oxygen is being transferred.

b. Never seal liquid oxygen in an unventilated container. If sealed off at room temperature, the liquid can develop a pressure of more that 12,000 psi. (82,740 kPa)

c. Do not substitute for approved equipment that is provided for handling liquid oxygen. The physical properties of many materials differ greatly at 297 degrees F (-183 degrees C) and room temperature. Rubber shatters like glass; some metals get brittle and lose their strength.

d. The extreme cold of liquid oxygen instantly produces painful burns if it contacts the skin. Protective equipment, consisting of a suitable face shield, apron, and gloves, must be worn when handling liquid oxygen.

e. Avoid touching bare metal lines that contain liquid oxygen because bare skin freezes instantly to the extremely cold metal.

f. When completely empty system is serviced, the liquid oxygen must be added slowly to cool the system equipment to the 297 degrees F (-183 degrees C) temperature. The equipment may be damaged by thermal shock of excessive pressure if the liquid oxygen is forced in too rapidly.

For inputs, comments, or questions please contact:


AMS1 Mark L. Starr

AZC(AW/NAC) Kimberly King