Jeff Guzzetti

1
Jeff Guzzetti

• Lubrication and
• End Play Inspection

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LubricationThe Procedure

• Gain access to the tail
• Remove access panels

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LubricationThe Procedure

• Apply grease to acme nut fitting with grease gun
  until grease exits out top of acme nut

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LubricationThe Procedure

• Brush application of light coat of grease onto
  jackscrew threads
• Operate jackscrew through full range of travel

BRUSH
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LubricationObservations

• Differences with method of application
• Small access panel
• Lube of nut fitting only is not adequate
• No inspection reqd
• Recommendations issued, and more proposed

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Jackscrew LubricationAlaska Airlines Interval
Extension
Alaska Airlines Interval
Manufacturer's Recommended Interval
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LubricationManufacturers Recommended Interval
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Maintenance IntervalsIssues

• Process is deficient
• Does not account for design assumptions
• Not supported by data
• Does not account for lack of task accomplishment

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The End Play CheckBackground

• DC-9 jackscrew life 30,000 hrs. - No Inspection
• 1965 Sampling program Premature wear found
  during bench checks
• Changes to acme screw wear limits
• On-wing End Play Check developed in 1967

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The End Play CheckBackground

• Ad Hoc procedure developed using tools already
  available to airlines
• Horizontal Stabilizer Restraining Fixture
• Dial Indicator
• Torque Wrench
• Purpose To check amount of thread wear without
  jackscrew removal

GAP
0.003 to 0.010
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The End Play CheckThe Procedure

• Move stabilizer to the 1 deg. ANU position
• Remove fairings
• Install restraining fixture between horizontal
  and vertical stabilizer
• (Continued)

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The End Play CheckThe Procedure (Continued)

• Clamp dial indicator to torque tube nut (below
  nut)
• Preload dial indicator
• Apply 250 300 in-lbs torque to shorten
  restraining fixture
• Record dial indicator reading (interpretation
  required)

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The End Play CheckThe Procedure (Continued)

• Relieve torque and ensure indicator returns to
  initial
• Repeat steps several times
• Check end play is between 0.003 and 0.040 inch.

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End Play CheckAlaska Airlines Interval Extension
Manufacturer's Recommended Interval
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The End Play CheckObservations

• Installation of dial indicator can affect end
  play reading

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The End Play CheckObservations

• Dial indicator can be difficult to read

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The End Play CheckObservations

• Working conditions can be adverse

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The End Play CheckObservations

• Restraining fixture condition, torque, and
  rotation direction can affect reading
• Jackscrew rotation during check can affect
  reading

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The End Play CheckObservations

• Differences w/ Alaska Airline fabricated
  restraining fixture

ALASKA AIRLINES TOOL
BOEING TOOL
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