12-66. In a wing fold system, what device prevents the wing fold handle from moving past the first stop when you 1. 2. 3. 4. are folding the wings? A hydraulic lock at the wing lock cylinder A hydraulic lock at the wing fold cylinder A spring-loaded mechanical latch at the wing lock cylinder A spring-loaded mechanical latch at the wing fold cylinder 12-67. In a wing fold system, the spring- loaded check ball of the thermal relief valve reseats at what prescribed pressure? 4,150 psi 3,970 psi 3,590 psi 3,360 psi 12-68. If the wing lock warning flags in a wing fold system fail to retract, you should consider this an indication of what problem? 1. The lockpins are failing to properly enter the lock fittings 2. The wing lock timer valve is not functioning 3. The hydraulic system pressure is insufficient 4. The wing fold cylinder is defective 12-69. In an ac generator drive system (hydraulically operated), when the return fluid exits the motor, it is routed through a heat exchanger and is cooled by what means? 1. By fuel 2. By ram air 3. By a compressor 4. By an electrically driven blower unit 12-70. To prevent overtemperature and/or reverse airflow in the engine compartment, the variable bypass bellmouth system is supplemented at low airspeeds and during ground operations by which of the following units? The bellmouth ring The aft variable ramp The auxiliary air doors The front variable ramp 12-71. When the control valve is in the neutral position in a bomb bay system,    the doors are held closed by what means? 1. A check valve 2. Mechanical locks 3. Hydraulic pressure 4. A hydraulic lock valve 12-72. When you are adjusting the blades to the parking area in a windshield wiper system, rotating a blade one serration will equal approximately how many degrees of rotation? 1. 10° 2. 2° 3. 3° 4. 5° 66