5-55. What  total  number  of  twists  should  be  in  a pigtail that is one-half-inch long? 1. Six to eight 2. Five to seven 3. Three to six 4. Four to five 5-56. Safety wire is installed properly if you observe which of the following actions? 1. The tension of the wire tends to tighten the bolt or nut 2. The tension of the wire tends to loosen the bolt or nut 3. The wire is as tight as possible 4. The wire has 5 turns per inch 5-57. What are the general classes of washers used in aircraft structures? 1. Plain, complex, and special 2. Plain, lock washer, and special 3. Castellated, castle, and plain 4. Castellated, lock, and plain 5-58. Lock washers are used with what type of nuts? 1. Castle 2. Plain hex 3. Elastic stop 4. Castellated shear 5-59. A star washer may be used what total number of times? 1. One 2. Two 3. Three 4. Four 5-60. What safetying device should be selected if it will   be   subjected   to   extreme   heat   and   high vibration? 1. Cotter pins 2. Snap rings 3. Tab lock washers 4. Safety wire 5-61. Tab washers may be used what total number of times? 1. One 2. Two 3. Three 4. Four 5-62. What  type  of  washers  are  widely  used  under AN   hex   nuts   to   provide   a   smooth   bearing surface? 1. Special washers 2. Star lock washers 3. Plain washers 4. Tab lock washers 5-63. What   class   of   washer   is   used   under   lock washers to prevent damage to surfaces of soft material? 1. Special 2. Castle 3. Complex 4. Plain 5-25