6-54. Following the first letter symbol identifying the engine type, a number appears to identify the service that uses the engine(s).    Which of the following   numbers   represents   an   Air   Force engine? 1. 20 2. 30 3. 31 4. 40 IN    ANSWERING    QUESTIONS    6-55    THROUGH 6-58, REFER TO TABLE 6-2 IN THE TEXT. 6-55. The     manufacturer's     symbol     BA     identifies which aircraft engine manufacturer? 1. Allison Division, General Motors Corporation 2. General Electric Company 3. Bell Aircraft Company 4. McDonald–Douglas Aircraft Company 6-56. What engine manufacturer's symbol identifies the Lockheed Aircraft Company? 1. LA 2. LD 3. AD 4. GA 6-57. The    manufacturer's    symbol    PW    identifies which aircraft engine manufacturer? 1. Rolls Royce, Ltd. 2. Westinghouse Electric Company 3. AiResearch Division, Garrett Corporation 4. Pratt and Whitney Aircraft Division 6-58. What engine manufacturer's symbol identifies the Curtis-Wright Corporation? 1. WE 2. WA 3. PW 4. MD 6-59. When two manufacturers' are jointly producing an engine, the symbol is one letter from each manufacturer's symbols. 1. True 2. False 6-60. The    third    part    or    section    of    the    engine designation  consists  of  a  dash  and  a  number indicating the model number.  The Navy model number   begins   with   2   and   continues   with consecutive even numbers. 1. True 2. False 6-61. Under special engine designations, what prefix letter  is  assigned  to  experimental  and  service test engines? 1. W 2. X 3. Y 4. Z 6-62. Under special engine designations, what prefix letter is assigned to restricted service engines? 1. W 2. X 3. Y 4. Z 6-63. Normally the restricted service designation for an engine is dropped after completion of what total number of qualifying test hours? 1. 50 hr 2. 100 hr 3. 150 hr 4. 200 hr 6-64. The MIL-STD-1812 engine designation system  is  made  up  of  what  total  number  of parts or sections? 1. One 2. Two 3. Three 4. Four 6-65. The Air Force, Navy, and Army are assigned a block of engine configuration model numbers that are used consecutively. 1. True 2. False 6-66. What  series  or  block  of  engine  configuration model numbers are assigned to the Navy? 1. 100 2. 400 3. 700 6-67. Which  of  the  following  characters  identifies the  type  of  engine  in  the  designation  number F401–PW–400? 1. F 2. 401 3. PW 4. 400 6-25