2.
The door is usually electrically-controlled and hydraulically-operated. You control the door from a panel on the partition behind the observer’s seat. The left hydraulic system supplies the door power through the DOWN circuit of the landing gear. The landing gear lever must be in the DOWN position when you use the door.
NOTE: THE LANDING GEAR CONTROLS A SAFETY SWITCH FOR THIS CARGO DOOR. BECAUSE OF THE SWITCH, YOU CANNOT OPEN THIS CARGO DOOR WHILE THE AIRPLANE IS IN FLIGHT. IF THIS SWITCH IS DAMAGED, THE DOOR WILL POSSIBLY NOT OPERATE.
CAUTION: DO NOT OPERATE THE MAIN CARGO DOOR WHILE THE AIRPLANE IS ONLY ON A JACK AT THE FORWARD JACK POINT. IF YOU OPERATE THE DOOR, YOU CAN CAUSE DAMAGE TO IT. YOU CAN ALSO CAUSE DAMAGE TO THE FUSELAGE.
CAUTION: DO NOT PUT THE MAIN CARGO DOOR IN THE USUAL OPEN (CANOPY) POSITION IN WINDS HIGHER THAN 68 MPH, 60 KNOTS (110 KM/HOUR). DO NOT PUT THE DOOR IN THE MAXIMUM OPEN POSITION IN WINDS HIGHER THAN 47 MPH, 41 KNOTS (75 KM/ HOUR). IT IS POSSIBLE TO OPERATE THE DOOR OVER ITS FULL RANGE IN WINDS AS HIGH AS 47 MPH, 41 KNOTS (75 KM/HOUR).
3.
You operate the door manually from the wheel well of the left landing gear (Figure 2-26). You move the control valve manually. Then the actuator pressure is supplied by the hand pump that is directly below the control valve.
4.
If you cannot operate the door with the usual procedure, you can open it from the external side as follows:
A. Remove all the access panels from the external surface of the door (see Figure 2-27).
B. Disconnect the hydraulic lines to one or more of the latch actuators (Detail A of Figure 2-27).
NOTE: USE CORRECT CONTAINERS OR DRAINAGE HOSES AT ALL OF THE OPEN HYDRAULIC LINES TO PREVENT CONTAMINATION OF THE AIRPLANE (WITH BMS 3-11 FLUID).
C. Remove the 5/16-inch (countersunk) bolts at each corner in the lower section of the door.
D. Fully open the two pressure doors. Do this with two persons who push on the top of each pressure door at the same time. Hold the doors in the open position with an applicable wood support (or other procedure).
E. Release the latches (four pairs of rotary latches) at the bottom of the door. You can do this if you push a special tool (B52020-1 wrench and adapter) against the lever on the rod end of the latch actuator. You must push each latch actuator to the extended position. Turn each lever 135 degrees clockwise until the piston touches the bottom in the latch actuator.
CAUTION: MAKE SURE ALL THE LATCH ACTUATORS ARE IN THE CORRECT PISTON BOTTOM POSITION. DO NOT PUSH THE CAMS OUT OF THEIR OVERCENTER POSITION BEFORE THIS OCCURS.
F. Use a 1/4-inch diameter rod in the holes from the removed bolts (Step 3). Use this rod to push each of the cams out of its overcenter position (Detail B of Figure 2-27).
2-40-4
MAIN DECK CARGO DOOR (757-200 COMBI AND PACKAGE FREIGHTER AIRPLANES ONLY) Page 2-59 Jul 01/2005 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：757 Airplane Recovery Document 飞机恢复文件(48)
