Aviation Electronics Technician 1 - Historic Naval Ships Association

sealing door of the chute. The chute may then be usedfor manually expending miscellaneous items less than7 inches in diameter. The size B chute has noconnecting electrical circuits.All of the size A SLTs in both aircraft haveelectrical connections that interface with the aircraftcomputer. There are also connections for the manualmode control circuits for sono inventory andlaunching.Sonobuoys, Mk 58 and/or Mk 25 marine locationmarkers (MLMs), and signal underwater sounds(SUSs) can be loaded into sonobuoy launchcontainers (SLCs). The Mk 25 MLMs and SUSs maybe dropped from the size B chute of the P-3C. After astore is loaded into the SLC, with the appropriate padsand spacers, an end cap is installed at the open endand marked with information of the enclosed store.The end cap has two protruding pin lugs, which matewith slots on the SLC to Iock the store in place. Thelugs shear when the cartridge-activated device (CAD)is fired. When the CAD fires, everything in the SLCis ejected.NOTE: Some sonobuoys may be receivedprepackaged in disposable SLCs. Thisdeletes the need for loading SLCs at theorganizational maintenance level.Before you load the SLCs into the SLTs, youshould perform a no-voltage and stray-voltage checkon the sono circuits at the sonobuoy safety switch forthe S-3A, and on the sono launch circuit tester in theP-3C. The safety switch on both aircraft is locatedadjacent to the SLTs and is actuated to the safeposition when the switch access door is open.The SLC, with CAD installed, is loaded into adesignated SLT according to the load plan. Thelocking lugs at the CAD cap mate with the lockinglugs of the SLT. The CAD is pressed against theelectrical firing pin in the SLT breech assembly. Inthe S-3A, tube P2 is always loaded with an SLCcontaining a search and rescue (S AR) sonobuoy.The P-3C also has a stowage rack inside the aircraftfor 36 SLCs for use in the four SLTs inside thecabin.When the SLCs are loaded, the areabeneath the loaded SLTs is cleared, and thesafety switch door is closed. When the door isclosed, the cockpit sono disabled indicationwill be extinguished. A continuity check isperformed by the aircraft circuits on the CADs,and the load status verified by using the sonoselect switches of the particular aircraft. Theswitch door is opened again, and the system isdisabled until just before takeoff. The loadplan is given to the tactical coordinator(TACCO) for computer programming of thespecific store in each SLT, and in the case ofthe P-3C, the stowage rack.Release of the SLT stores in flight is normallyactivated by the aircraft computer. The computeris programmed by the TACCO and controlled bythe pilot’s or TACCO’s keyset in the P-3C. In theS-3A, the TACCO’s keyset programs andcontrols the computer. The manual release modeis normally used only during maintenance testingand system checks, and as an emergency backupfor the auto mode. Emergency jettison of theSLTs is not included in the P-3C system. In theS-3A, it is part of the jettison circuit, and whenactivated, will jettison 59 of the 60 SLCs in lessthan 10 seconds. Until the pilot initiates circuitactivation, the SAR buoy will remain in the P2chute.CAUTIONWhen either type of aircraft is on the deck,the switch access door should be open toprevent inadvertent firing of the SLTstores. Inadvertent firing may cause injuryor death to personnel, and will causedamage to the equipment.HELICOPTER SEARCH STORE SYSTEMThe search store system of helicopters is lesscomplex than that of the fixed-wing aircraft justdiscussed, but it serves the same purpose. Figure7-22 shows some of the basic search store equipments7-14