to their designed shape within 30 seconds; however, depending on ambient temperature, they may require additional air pressure. Air pressure can be added by unscrewing the locking device, pushing in on the valve, and blowing air into the preserver through the oral inflation tube. The LPU-23A/P or the LPU 24A/P life preserver assemblies have an automatic inflation device designated the FLU-8A/P.
The FLU-8A/P automatic inflation assembly consists of a body assembly and a sensor housing. The body assembly contains a cartridge, piercing pin, spent-cartridge indicator, firing check port, packing loop, cam lever, lanyard assembly, and nylon release pin. The body assembly also provides for the attachment of a c h a r g e d C O2 c y l i n d e r . T h e s e n s o r h o u s i ng contains an electronic circuit, two batteries, and a sensor plug assembly containing the battery contact spring and the sensor pin. The inflation devices are attached to each valve stem located on the waist lobes. In addition, a beaded handle with a manual inflation lanyard is connected to each inflation device.
NOTE: TheFLU-8A/P can be operated either manually or automatically, although the manual mode is considered the primary mode.
MANUAL MODE. - The attached lanyard assembly, when pulled, rotates the cam lever, releasing the packaging loop lanyard from the nylon release pin and forcing the piercing pin into the diaphragm of the CO2 cylinder. The CO2 , under pressure, is forced through the body of the device to inflate the life preserver.
AUTOMATIC OPERATION. - The secondary operating mode is automatic. Upon immersion in freshwater or salt water, a conducting path is established between the sensor pin and the case, completing the electrical circuit. A resistance network requires the conductivity of the water to be at an established minimum. If the conductivity is present, two series-connected, dry-storage batteries energize the electronic circuit, which then discharges to fire the cartridge. B a l l i s t i c e n e r g y , p r o d u c e d b y t h e b u r n i ng cartridge, forces the spent-cartridge indicator pin into the firing check port and propels the piercing pin into the diaphragm of the CO2 cylinder. As the piercing pin moves forward, the packaging loop lanyard is released from the body of the inflator. The CO2, under pressure, is forced through the body of the device to inflate the life preserver.
NOTE: TheFLU-8A/P is an emergency backup system. Always, if possible, manually inflate the LPU prior to water entry.
These life preservers provide buoyancy that ranges from 29 to 65 pounds. This may confuse the aircrewmen; so it should be pointed out that this is the minimum buoyancy the preserver provides and that the natural b u o y a n c y o f t h e b o d y p r o v i d e s a d d i t i o n al
Figure 5-3. - Aircrewman grasping shoulder straps.Continue Reading