pressurization is provided by a controlled flow of air bleed motors, which passes through the air conditioning system and is then taken to the pressurized areas. Pressurization desired levels are maintained by regulating the compressed air escaping through the outlet valve (outflow valve). Normally, the outflow valve is automatically regulated by a dual system automatic pressurization control the cabin pressure from takeoff to landing.
For automatic operation of the outflow valve control lever CABIN ALT should be up. Rotate the control wheel adjusts as pressurization. A position indicator, next to the wheel, will move to indicate the position of the valve.
For manual operation of the outflow valve control lever must be down CABIN ALT. To maintain pressurization must manually press the wheel and rotate in the desired direction. The indicator will move in the same direction to indicate the position of the valve.
Relief valves are installed to protect the aircraft structure of the maximum pressure or pressure from a possible rupture of a pipeline-wing anti-ice system. Relief valves limit cabin differential between 7.95 and 8.27 psi. The differential threshold is 8.32 psi. A negative differential is relieved by the inward movement of the hallmarks of the galley doors and access doors, and a relief valve in the pressurization rear bulkhead.
With the aircraft on the ground, the dual system of pressurization start pressurizing the cabin when the throttles are positioned to launch a 60 sec timer is actuated. In the case of abort takeoff, the cabin depressurized automatically start when the throttles are retarded. If the airplane passes flight mode within 60 seconds after the accelerators have been developed, the cabin is depressurized. With the aircraft in flight, the cabin pressure is controlled automatically. During the climb, cruise and descent maintain cabin altitude profile set by set, which is a function of altitude of the aircraft.
Double automatic pressurization system consists of two identical but independent systems, powered by different power sources are controlled by the selector panel cabin pressure. A control system has main while the other serves as backup.
If there is a manual or automatic transfer before landing, resulting in a subsequent block automatic transfers or exchanges after the landing system. TRANSFR lights STDBY ON LOCKOUT and lit and should not be reset. This will help to identify which system Maneno failed.
If the performance support system (STDBY) is not satisfactory, the primary system can be re selected to carry the selector switch STDBY and then back to PRIMARY. Manual selection allows you select the system that has better performance. Do not reset the light TRANSFR LOCKOUT. This inhibits any automatic transfer system works best. Motors
The aircraft is powered by two Pratt & Whitney JT8D turbofan axial flow. In addition to delivering thrust, the engines provide pneumatic pressure for pressurization, air conditioning, anti freezing and thawing. They are protected by a system of fire detection and suppression.
The fire protection system provides continuous detection of fire from both engine and APU, warning alerts crew by visual, aural and vocal. The aircraft is equipped with the ability to extinguish the fire in each engine or APU compartment. Push
Engine: Engine Type
Push Push Normal Takeoff Maximum Takeoff
JT8D-209 18,500 lbs 19,250 lbs
JT8D-217 20,000 lbs 20,850 lbs
JT8D-217 20,000 lbs 20,850 lbs
JT8D-217C 20,000 lbs 20,850 lbs
JT8D-219 21,000 lbs 21,700 lbs

equipped with an automatic reserve thrust (ART Automatic Reserve Thrust), which in the case of an engine failure, the ART system, when operating, increase the thrust on the operating engine.
The reversers are used only on land, are hydraulically actuated. The reverser consists of two doors (spoilers), as part of the rear of the nacelle when held. When extended, the doors leading the exhaust gases above and below the nacelle. To prevent accidental extension, separate hydraulic barriers prevent the thrust reverser to move out of position held until reverser lever is moved to the reverse position. Starting Engine
:
Any engine can be started using a pneumatic pressure supply, the opposite motor can be turned on using the cross-feed system of pneumatic pressure.
A valve power (Start Valve) controlled electrically and pneumatically actuated controls installed on each motor starter each. The start valve regulates air pressure to maintain a certain pressure that is delivered to the starter.
The panel switches are located motor L and R the positions START ON / OFF. When any of the switches is kept ON, the respective start valve opens, lights in the annunciator panel light L or R START VALVE OPEN indicating that the valve is open. When the switch is released, the respective start valve closes and the announcement goes out. To extend life and reduce the possibility of cutting the starter shaft, re not engage the starter when the compressor is running.

Automatic Reserve Thrust System (ART):
The ART combines the features of the DFGC (flight guidance computer) and fuel control JT8D-200 engine to deliver maximum power in the event of an engine failure during a normal takeoff thrust. By acting on ART, the thrust is increased without moving the throttle lever by opening a valve actuated by a solenoid in the fuel control both engines.
The ART system is ready to operate when the aircraft on the ground, the switch is in AUTO ART, any slat is extended, both engines are running at idle, and automated testing of ART is complete. The system is further reinforced when the N1 in both engines as high as 64%. ART
The system operates when the DFGC detects any of the following: gap of more than 30.2% of N1, data N1 invalid, DFGC failure, loss of power or manual gearbox DFGC. When acting, the ART increases the operating engine EPR thrust to maximum thrust normal (an increase of approx.. 05 EPR) by opening a valve in the fuel control. Once the ART function is latched until the switch is moved to OFF ART.
