2.
When you use a rope line, the end is an important part of the line strength. Here are two examples:
A. An eye splice around a thimble in the end decreases the line strength to 90 percent of the maximum permitted load.
B. A knot in the rope end decreases the line strength to 60 percent of the maximum permitted load.
3.
Use pads if it is necessary to prevent damage to the lines from sharp edges.
4.
Before you install the tether lines, you must examine all the lines for their safety. Do a check of the external surfaces. Look for the worn areas and the rust areas. Also, look for the cut strands or broken strands.
5.
If you use a fiber rope, twist the strands open. Then examine the internal area. Look for some deterioration or broken strands. Do not use a rope that has kinks or knots from a heavy load.
6.
Make a careful inspection of a steel cable that has some kinks.
7.
In wet weather operations, the length of a manila line gets smaller. During such times, you must make a check that the lines are not too tight. You can easily put a high load into the structure of the airplane. Also, if a wet manila line is frozen, it can easily be broken.
Figure 3-2 TETHERING (STABILIZING) LINE MATERIALS DATA
NOMINAL DIAMETER TETHER (STABILIZING) LINE, MINIMUM BREAKING STRENGTH
(ABACA) MANILA FED. SPEC. TR 605 DUPONT DACRON NYLON DOUBLE NYLON BRAID STEEL CABLE (6 X 19 WITH FIBRE CORE)
3/16 (5) 3,100 (1406)
1/4 (6) 5,480 (2486)
5/16 (8) 8,520 (3865)
3/8 (10) 12,200 (5534)
7/16 (11) 16,540 (7503)
1/2 (13) 2,650 (1202) 6,100 (2767) 6,650 (3016) 7,500 (3402) 21,400 (9707)
5/8 (16) 4,400 (1996) 9,500 (4309) 10,000 (4536) 12,000 (5443) 33,400 (15150)
3/4 (19) 5,400 (2449) 13,200 (5988) 14,600 (6623) 17,000 (7711) 47,600 (21591)
7/8 (22) 7,700 (3493) 17,500 (7938) 19,600 (8891) 23,700 (10750) 64,400 (29212)
3-20-2
TETHER LINES
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Figure 3-2 TETHERING (STABILIZING) LINE MATERIALS DATA (Continued)
NOMINAL DIAMETER TETHER (STABILIZING) LINE, MINIMUM BREAKING STRENGTH
(ABACA) MANILA FED. SPEC. TR 605 DUPONT DACRON NYLON DOUBLE NYLON BRAID STEEL CABLE (6 X 19 WITH FIBRE CORE)
1 (25) 9,000 (4082) 22,000 (9979) 25,000 (11340) 28,500 (12928) 83,600 (37921)
1 1/4 (32) 13,500 (6124) 30,500 (13835) 37,800 (17146) 44,000 (19958) 129,200 (58605)
NOTE: 1. THE SAFE WORKING LOAD-TO-BREAKING STRENGTH MUST BE A 1 TO RATIO 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(60)
