(3)  
Detector locations.

 (a)  The engine fire detectors are installed:
 1)  on the right and left sides of the low-pressure compressor case lower sector (zone 1)
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 2) on the underside of the engine strut, above the combustion case (zone 3) 3) around the turbine case lower sector (zone 3).
 (b)  The nacelle overheat detectors are installed behind the precooler air inlets, in the pneumatic ducting area.
 B. Fire and Overheat Detection Cards
_________________________________
 (1)  
Each detection loop has a corresponding detection control card. These cards constantly monitor and process signals produced by each loop. The cards output alarm or fault signals to the fire/overheat logic/test card for the appropriate system.

 (2)  
The detection control cards are in the P54 fire detection card file. The card file is in the electrical/electronic equipment compartment, along the right side of the nose gear wheel well.

 C. Fire/Overheat Logic/Test Cards
______________________________
 (1)  
Two AFOLTS (Automatic Fire/Overheat Logic/Test System) cards interpret detection control card signals, provide system functional tests, and output fire/overheat warning and fault indication signals. Each card handles the fire and overheat detection systems for one engine.

 (2)  
The AFOLTS cards are located in the P54 card file.

 D. Fire/Overheat Test Panel
________________________
 (1)  
The fire/overheat test panel contains a momentary pushbutton switch - ENG/APU/CARGO. This switch initiates a test of the fire, overheat, and smoke detection systems for the engines, APU, and cargo compartments. The test results in cockpit fire and overheat indications.

 (2)  
The test panel also has an amber SYS FAIL - FAIL P-RESET switchlight. This switchlight indicates a fire, overheat, or smoke detection system failure. The switchlight is pressed to reset.

 (3)  
The fire/overheat test panel is on aft pilots' control stand P8.

 3. Operation (Fig. 2 and 3)
_________
 A. Functional Description
______________________
 NOTE: The Engine Turbine Cooling Overheat Detection System works in a
____ similar way as the Engine Fire/Overheat System. Some indications displayed may be the same with either system. Refer to AMM 26-13-00/001 for the descripion and applicable a indications of the Engine Turbine Cooling Overheat Detection System.
 (1)  AIRPLANES WITH SYSTRON DONNER FIRE DETECTORS;
 Refer to the data that follows:

 (a)  With 28-volt dc power applied to the systems, current is sent from each control card to the detectors in the corresponding loop. Each detector element has a resistance value, and is in parallel with the other elements in its loop. Thus, each loop has an equivalent resistance value, and the control card senses a loop voltage potential.
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LOOP 2 FIRE DETECTOR CARD  AUTOMATIC FIRE/OVERHEAT LOGIC TEST CARD (AFOLTS)
Engine Fire Detection Schematic (Example)Figure 2
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AUTOMATIC FIRE/OVERHEAT LOGIC TEST CARD (AFOLTS)
Nacelle Overheat Detection Schematic (Example)Figure 3
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