USCGQ
Log in Start free
USCGQ
Toggle sidebar
Home
Engine
Retired questions · Gas Turbines
Start practicing

Engine · 145 questions

Retired questions · Gas Turbines - USCG Exam Questions

These are retired questions the Coast Guard no longer draws exams from. They stay online for reference; the current questions are in Gas Turbines.

Gas turbine theory, construction, operation, and the support systems found in gas turbine propulsion plants.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

Random question Start at question 1 Build a timed exam

All Retired questions · Gas Turbines questions

Questions 1–100 of 145 · page 1 of 2

  1. #1 Compared to other types of engines, what is the biggest advantage of a GTE?
  2. #2 The term "divergent" is best described as _________.
  3. #3 Which of the following terms refers to stator blades?
  4. #4 What are the two common forms of blade roots?
  5. #5 In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by the ______...
  6. #6 Which of the following factors permits a gas turbine to produce 100% power?
  7. #7 How do the high-velocity high-temperature gases cause the rotor of a gas turbine to rotate?
  8. #9 An "open cycle" of a gas turbine is best described by which of the following statements?
  9. #11 A gas turbine in which exhaust gas heat energy is added to the air charge between the compressor and combustion chamber is classified as a/an?
  10. #12 The purpose of the metal spray rub coating on the rotor and stator casing of a marine type gas turbine is to _________.
  11. #13 The basic components of a gas turbine gas generator include which of the following?
  12. #14 What is the function of the stator in a gas turbine compressor?
  13. #15 A pressure stage of a gas turbine compressor consists of which of the following?
  14. #16 Before combustion can occur, the combustion air must be delivered to the combustor at a high-pressure and low-velocity. High-velocity, low-pressure ai...
  15. #17 Why are loose-fitting blades used on the first several stages of large compressors?
  16. #18 What is the disadvantage of a dual-entry centrifugal compressor compared to a single- entry centrifugal compressor?
  17. #20 What is a midspan platform?
  18. #21 Which of the following designs is the most satisfactory method for attaching turbine blades?
  19. #22 Turbine disks are commonly attached to the shaft by which of the following methods?
  20. #23 What are the two common methods of power turbine blade retention?
  21. #26 What method is utilized to allow nozzle blades to withstand high inlet temperatures?
  22. #29 In the marine gas turbine engine shown in the illustration, the purpose of the COWL and diffuser assembly installed in the combustor is to provide ___... illustration
  23. #31 Which type of GTE can handle a larger volume of air?
  24. #32 Which of the following is an advantage of a single-shaft GTE compared to a split-shaft GTE?
  25. #34 What type of air seal is used in the sump and turbine areas of a GTE?
  26. #35 What type of air seal is used in the combustor and turbine midframe of a GTE?
  27. #36 What type of seal is used in the gearbox of a GTE?
  28. #39 What type of starter is commonly used on smaller GTEs?
  29. #42 During a "hung start" of a GTE, which of the following conditions will occur?
  30. #44 Petroleum based lubricating oils are NOT suitable for use in GTEs for which of the following reasons?
  31. #46 The purpose of the air/oil separator as shown in the illustration of a typical gas turbine lube oil system is to _________. Illustration GT-0024 illustration
  32. #47 The sensors which transmit remote system temperatures on marine gas turbines are usually constructed as __________.
  33. #49 The lube oil scavenge pressure on the marine gas turbine shown in the illustration, is sensed by a ___________. Illustration GT-0017 illustration
  34. #51 The main lube oil system pump check valves serve to maintain system prime and perform which of the following other functions?
  35. #53 When the main reduction gear lube oil system is secured, which of the following components maintains the air within the casing at less than 35 percent...
  36. #54 How is the lube oil supplied to each bearing in a GTE controlled?
  37. #55 On the marine gas turbine lube oil system shown in the illustration, air and oil are separated in the air/oil separator mainly by the use of _________... illustration
  38. #56 The main lube oil system used on the marine gas turbine engine shown in the illustration, is classified as a __________. Illustration GT-0017 illustration
  39. #57 On the marine gas turbine engine as shown in the illustration, the main lube oil system is cooled by ________. Illustration GT-0017 illustration
  40. #58 If the lube oil scavenge temperature exceeds 300 degrees F on the marine gas turbine engine shown, and reducing power does NOT bring the temperature w... illustration
  41. #62 The fuel oil system of a GTE provides all EXCEPT which of the following?
  42. #63 What is the power source for the ignition exciter of a GTE?
  43. #64 In the ignition system of a GTE, how is optimum spark achieved?
  44. #65 What is the most common type of spark igniter used on a GTE?
  45. #66 Which of the following statements is true concerning the fuel oil ignition system of the marine gas turbine engine shown in the illustration? Illustra... illustration
  46. #67 The lubrication principal used by the Kingsbury thrust bearing is _________.
  47. #68 The main thrust bearing directly positions which part(s) of the main reduction gear?
  48. #69 The purpose of the main reduction gear in a marine gas turbine propulsion installation is to _________.
  49. #70 On some marine gas turbine reduction gear arrangements, the reduction gear lube-oil supply pump may also supply oil to which of the following componen...
  50. #76 What is the purpose of the CPP hydraulic oil power system?
  51. #77 On the marine gas turbine shown in the illustration, the power turbine inlet pressure probes would be mounted nearest the area labeled _______. Illust... illustration
  52. #78 On the marine gas turbine shown in the illustration, the fuel oil inlet temperature is sensed by _________. Illustration GT-0017 illustration
  53. #79 On most marine gas turbines used aboard ships, vibration sensors are identified as _________.
  54. #80 On the marine gas turbine shown in the illustration, the compressor "inlet pressure" sensor would be located nearest the area labeled _________. Illus... illustration
  55. #81 On the gas turbine engine shown in the illustration, the "T5.4" thermocouples are _________. Illustration GT-0006 illustration
  56. #82 When auto starting a GTE similar to the one shown in the illustration, a "False Start" indication will initiate if which of the following conditions o... illustration
  57. #84 On a ship with marine gas turbine engines as shown in the illustration, when the engine is operating normally, the enclosure heater will _________. Il... illustration
  58. #85 In a GTE propulsion installation, the typical control system is designed to perform which of the following three functions?
  59. #86 What type of pliers are designed to reduce the time used in twisting wire on nuts and bolts?
  60. #87 To gain access to a nut or bolt in an area that is hard to reach, you should use what type of wrench?
  61. #88 With the exception of having a slot cut in the wrench head, a flare nut wrench is similar to what other wrench?
  62. #89 Wrenches that are recommended for use on GTEs should be plated with which of the following elements?
  63. #90 When you are using a stroboscope, if the flash speed is faster than the rpm of the object being tested, what effect will this appear to have on the ob...
  64. #91 Which of the following instruments is designed to help you when performing an internal inspection of the GTE?
  65. #92 Cadmium plated tools should NOT be used when performing maintenance on gas turbines because cadmium particles may become imbedded and cause embrittlem...
  66. #93 Inspection mirrors are commonly used for which of the following purposes?
  67. #94 4. All marine gas turbine engine references, enclosure references, and clock positions apply to viewing the gas turbine engine shown in the illustrati... illustration
  68. #95 Routine water washing of the marine gas turbine engine compressor shown in the illustration, is usually performed while operating _______. Illustratio... illustration
  69. #96 When removing the marine gas turbine engine as shown in the illustration, how is the engine removal accomplished? Illustration GT-0022 illustration
  70. #98 While standing watch on a ship in the engine room with marine gas turbine engines as shown in the illustration, if after reducing power in response to... illustration
  71. #99 On a vessel equipped with marine propulsion gas turbines, the operators initial response to a high vibration alarm should be to _________.
  72. #100 While standing watch underway on a ship with marine gas turbines shown in the illustration, a fire emergency stop is initiated when __________. Illust... illustration
  73. #101 The two main types of "compressor" stalls are known as _________.
  74. #103 What is the purpose of the LM2500 GTE enclosure heater?
  75. #105 Where are the CO2 nozzles located in the LM2500 enclosure?
  76. #106 What type of combustor is used by the LM2500 GTE?
  77. #107 The gas generator section of the LM2500 GTE is composed of all of the following components EXCEPT which one?
  78. #108 The struts of the compressor front frame provide passages for all of the following mediums EXCEPT which one?
  79. #109 What is the primary purpose of the diffuser and distributor on the LM2500 GTE?
  80. #111 How is the HP turbine rotor of the LM2500 GTE cooled?
  81. #112 How many stages are in the HP turbine of the LM2500 GTE?
  82. #113 The power turbine (PT) of the LM2500 GTE has a total of how many stages?
  83. #114 What is the primary function of the main fuel control on the LM2500 GTE?
  84. #115 As shown in the illustration of a gas turbine fuel oil system, when the engine fuel oil valves are de-energized, the remaining fuel left in the system... illustration
  85. #116 In order to get a ready indication for a normal start with an LM2500 marine gas turbine, what permissive must be met?
  86. #117 In the marine gas turbine engine shown in the illustration, the 9th stage bleed air is used for __________. Illustration GT-0017 illustration
  87. #118 In the marine gas turbine engine shown in the illustration, the 13th stage bleed air is used for __________. Illustration GT-0017 illustration
  88. #119 In the marine gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle vanes are cooled by __________. Illustration GT-0020 illustration
  89. #120 As shown in the illustration, the HP turbine 2nd stage blades are cooled by convection, with the cooling air being discharged at the _________. Illust... illustration
  90. #122 Boyle's law can best be defined as _________.
  91. #123 In the operation of a marine propulsion gas turbine, kinetic and thermal energy required to drive the main propeller shaft are extracted by the ______...
  92. #128 What type of gas turbine cycle configuration is shown in the illustration? See illustration GT-0031 illustration
  93. #130 Based on the data shown in the illustration, which statement of the following is correct? Illustration GT-0030 illustration
  94. #132 Which of the following statements about the intercooled-recuperated gas turbine cycle is true? Refer to Illustration GT-0031 illustration
  95. #133 For shipboard main propulsion application, how does a Intercooled-Recuperated (ICR) cycle gas turbine configuration compare to a Combined Cycle gas tu...
  96. #137 What action should you take if full power vibration limits are exceeded on a GTE?
  97. #140 The two main types of "compressor" stalls are known as _________.
  98. #141 To prevent overheating of the illustrated turbine blade, which of the following fluids is circulated through it via the shaped internal passages? See... illustration
  99. #147 Your first step in response to a GTE high lube oil sump temperature alarm would be __________.
  100. #149 The secondary passages on the gas turbine engine fuel nozzles shown in the illustration are designed to open at approximately what pressure? See illus... illustration

Gas Turbines questions: what to expect

Q How many Gas Turbines questions are in the Engine pool?

This retired set holds 145 Gas Turbines questions the Coast Guard no longer draws on exams. They stay online for reference; the current Gas Turbines module is the one to study.

Q What score do I need to pass the Gas Turbines module?

Most USCG exam modules, including Gas Turbines, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Gas Turbines exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

Other Engine modules

About the Engine question pool

The Engine pool holds the current U.S. Coast Guard questions for engineering credentials, from QMED ratings through DDE and Assistant Engineer up to Chief. Answer any question to see the correct choice instantly.