AD 2/3

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AD 2/3
2011-02-19 01:54:16
Assignment eleven

Power plant troubleshooting and power plant inspection, repair and testing
Show Answers:

  1. To allow comparison with MIMs serviceability limits during borescoping, you should record what information?
    area, magnitude, and direction of damage
  2. Cleaning the engine compressor by water washing is required before any borescope inspection so sulfidation does not hide damage.
  3. Which program defines the engine repair capabilities of an AIMD power plants section?
    Gas Turbine Maintenance Program
  4. Which condition determines the different maintenance actions for specific engines?
    degree of difficulty and frequency of repair
  5. What degree of gas turbine engine repair, if any, is the same as complete engine repair (CER)?
    first degree
  6. Which is the a purpose for cleaning engine parts?

    Remove sulfidation from turbine blades?
    prepare surface for repair?
    Permit a thorough inspection?
    each of the above
  7. The selection of cleaning materials and processes is determined by the degree of cleanliness required and nature of soil only.
  8. Which of the following practices should you follow when you steam cleaning parts?

    avoid heat buildup?
    thoroughly dry all parts after cleaning?
    apply a corrosion prevention compound?
    all of the above
  9. What cleaning process would you use to remove paint and rust?
  10. Cleaning magnesium and steel parts in the same cleaning tanks could cause what problem?
    corrosion damage to magnesium parts
  11. Provided there is no indication of pieces breaking away, cracks are allowed without repair on what type of vane?
    the concave surface of rubber-filled vanes
  12. When inspecting combustion liners, what is the maximum allowable number of air hole cracks per section (0.125 inch or less)?
  13. Burned combustion liners may be left in service provided the burn is NOT in which area?
    the crossover tubes
  14. Cracks in the combustion chamber support may be repaired using what method?
    inert-gas welding
  15. Operating turbine blades are more easily damaged than compressor blades because turbine blades operate under what extreme condition?
  16. High-temp corrosion known as sulfidation is caused the interaction of what chemical compounds and elements?
    fuel/air misture, sodium and sulfur only
  17. Sulfidation has a more harmful effect on compression blades than on turbine blades.
  18. What condition is considered serious when the turbine rotor is sulfidated?
    splitting, delamination, flaking, all of the above
  19. When checking for stress rupture cracks, you should check which sections on the turbine blades?
    across the leading and trailing edges at right angles to the edge length
  20. The leading edge of a first-stage turbine blade of an engine has stress rupture cracks. What condition is most likely the cause of the cracks?
    an overtemperature condition
  21. What is NOT a reason to mark engine parts?
  22. When using abrasive blasting you may use only the wet type.
  23. Temporary markings maintain identification of parts after a modification to that part.
  24. Marking of hot section components that are directly exposed to the gas path may be accomplished using what item?
    layout dye
  25. Any temporary marking method that you use that leaves a heavy carbon deposit on hot section components may cause what type of corrosion?
  26. What method of marking provides permanent markings?
    metal stamp, vibropreen, and acid-etching
  27. Using engine stands and special fixtures to support the engine during disassembly and buildup provides what advantage?
    prevents stress and allows proper alignment of parts
  28. Nuts and bolts used in the hot section of an engine are normally of what type?
    special heat-resistant material
  29. When a complete replacement of the entire compressor case is accomplished, it is also necessary for you to replace the compressor rotor.
  30. What is elongation of the blade?
  31. What is transfer of metal from one surface to another?
  32. What is a bent blade of ragged edge?
  33. What is the smooth repair into the surrounding contour?
  34. When, if ever, is the straghtening of bowed compressor vanes permissible on the inner half of the blade?
  35. When blending compressor vanes, you should use which of the following procedures?
    grind/file the blade lengthwise
  36. What material should you use to polish a reworked area to make it feel like the original?
    a fine abrasive stone
  37. At what location is the code letter stamped on a blade?
    next to, but not after, the part number
  38. Compressor stator vanes are blended to minimize stress that tends to concentrate in what areas?
    dents, scratches, and cracks
  39. When parts of the vane are damaged beyond maximum repair limits, they should be sent to what facility?
    overhaul activity
  40. Damage to the tailing edge of the hollow vanes can be blended if what portion of teh weld seam remains after the repair?
  41. What record would you refer to when classifying replacement turbine blades?
    the turbine rotor disc assembly service record
  42. One hundred percent turbine blade replacement is allowable provided the pan weight of the replacement blades matches the original weight within what prescribed limit?
    +/-1 gram
  43. Hot spots found on the exhaust cone can be attributed to what condition?

    Improper combustion liner flame control?
    A malfunctioning fuel nozzle?
    Engine operation at 100% rpm for long periods of time?
    both 1 and 2 above
  44. Engine adjustment is best accomplished during controlled operation of the engine. Manuals and procedures are established for the use of test facilities/test cells by what authority?
  45. Operators of test facilities may be certified by one of three methods. Two of these methods are formal training at NADEP and on-site training provided by a NAESU engineer. What is the third method?
    OJT under the direct supervision of a certified test stand operator
  46. All test cell operators must hold a valid support equipment license that contains what info?
    a particular engine and engine test cell
  47. All certified test cell operators must hold a valid support equipment license. You should refer to what pub to determine training and licensing procedures?
    OPNPVINST 4790.2 (series)
  48. Engine test cells are equipped to measure what parameters?
    all desired engine operating parameters
  49. The enclosed test facility is capable of handling how many pounds of thrust during the engine performance test?
    17,000 lbs
  50. The enclosed test facility includes test equipment made up of a total of how many major assemblies?
  51. For what reasons is the variable height stand used when testing an engine?
    to support the engine, to restrain the engine, and to position the engine
  52. By what means is the interlock system started?
    electrically, with the 28-volt dc motor-generator set switch
  53. On the control board, when the toggle is raised, the switch is in what position?
  54. The two mating pilot lights on the interlock system indicate the key switch position. What color light indicates CLOSED?
  55. Improper sizing and positioning of the first-stage augmenter may result in what problems?
    Increase in EGT, loss of thrust, and insufficient secondary airflow
  56. The fuel system of the enclosed test facility is interlocked to the basic interlock system, to the CO2 fire-extinguishing system, and to what other system?
    Exhaust Gas cooling system
  57. Initial rotation of an engine during starting may be accomplished by an electrically operated starter motor or what other starting method?
    compressed air-operated turbine starter
  58. For complete fire control coverage, the CO2 system is electrically linked to the interlock system. By what means is the system linked to the main fuel line valve of the engine fuel supply?
    pressure connect
  59. What is the primary purpose of the refrigeration system in the CO2 fire system?
    to maintain a nominal storage tank pressure
  60. Portable universal engine runup test systems may be used at any site that has what accomodations?
    adequate tie-downs
  61. At the end of an engine test, the operator will record the engine coast-down time. What definition best defines coast-down time?
    time elapsed from fuel cutoff to complete engine stop
  62. Shorter than normal coast-down time may be caused by what problem?
    compressor rub due to elongated blades