jeff guzzetti lubrication and end play inspection lubrication and end play inspection

Jeff GuzzettiJeff Guzzetti

Lubrication and

End Play Inspection

Lubrication and

End Play Inspection

Lubrication:The ProcedureLubrication:The Procedure

• Gain access to

the tail

• Remove access

panels

• Gain access to

the tail

• Remove access

panels

Lubrication:The ProcedureLubrication:The Procedure

• Apply grease to

acme nut fitting with

grease gun until

grease exits out top

of acme nut

• Apply grease to

acme nut fitting with

grease gun until

grease exits out top

of acme nut

FAIRING

ACCESS PANELS

GREASE GUN

Lubrication:The ProcedureLubrication:The Procedure

• Brush application of

“light coat of grease”

onto jackscrew threads

• Operate jackscrew

“through full range of

travel”

• Brush application of

“light coat of grease”

onto jackscrew threads

• Operate jackscrew

“through full range of

travel”BRUSHBRUSH

Lubrication:ObservationsLubrication:Observations

• Differences with method of application

• Small access panel

• Lube of nut fitting only is not adequate

• No inspection req’d

• Recommendations issued, and more proposed

• Differences with method of application

• Small access panel

• Lube of nut fitting only is not adequate

• No inspection req’d

• Recommendations issued, and more proposed

Jackscrew Lubrication:Alaska Airlines Interval ExtensionJackscrew Lubrication:Alaska Airlines Interval Extension

0 1000 2000 3000 4000FLIGHT HOURS

1996

1994

1991

1988

1987

YE

AR

0 1000 2000 3000 4000FLIGHT HOURS

1996

1994

1991

1988

1987

YE

AR

Manufacturer's Recommended IntervalAlaska Airlines Interval

Lubrication:Manufacturer’s Recommended Interval Lubrication:Manufacturer’s Recommended Interval

0 1000 2000 3000 4000FLIGHT HOURS

1996

1965

1964

YE

AR

0 1000 2000 3000 4000FLIGHT HOURS

1996

1965

1964

YE

AR

Maintenance Intervals:IssuesMaintenance Intervals:Issues

• Process is deficient

• Does not account for design assumptions

• Not supported by data

• Does not account for lack of task accomplishment

• Process is deficient

• Does not account for design assumptions

• Not supported by data

• Does not account for lack of task accomplishment

The End Play Check:BackgroundThe End Play Check:Background

• 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

• 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

The End Play Check:BackgroundThe End Play Check:Background

• 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

• 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

The End Play Check:The ProcedureThe End Play Check:The Procedure

• Move stabilizer to the 1

deg. ANU position

• Remove fairings

• Install restraining fixture

between horizontal and

vertical stabilizer• (Continued)

• Move stabilizer to the 1

deg. ANU position

• Remove fairings

• Install restraining fixture

between horizontal and

vertical stabilizer• (Continued)

The End Play Check:The Procedure (Continued)

The End Play Check:The 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)

• 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)

The End Play Check:The Procedure (Continued)

The End Play Check:The 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.”

• Relieve torque and ensure indicator returns to initial

• Repeat steps several times

• Check end play is “between 0.003 and 0.040 inch.”

End Play Check:Alaska Airlines Interval ExtensionEnd Play Check:Alaska Airlines Interval Extension

0 2000 4000 6000 8000 10000FLIGHT HOURS

1996

1988

1985

YE

AR

0 2000 4000 6000 8000 10000FLIGHT HOURS

1996

1988

1985

YE

AR

Manufacturer's Recommended Interval

The End Play Check:ObservationsThe End Play Check:Observations

• Installation of dial indicator can affect end play reading

• Installation of dial indicator can affect end play reading

The End Play Check:ObservationsThe End Play Check:Observations

• Dial indicator can be difficult to read

• Dial indicator can be difficult to read

The End Play Check:ObservationsThe End Play Check:Observations

• Working conditions can be adverse

• Working conditions can be adverse

The End Play Check:ObservationsThe End Play Check:Observations

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

• Jackscrew rotation during check can affect reading

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

• Jackscrew rotation during check can affect reading

The End Play Check:ObservationsThe End Play Check:Observations

• Differences w/ Alaska Airline fabricated restraining fixture

• Differences w/ Alaska Airline fabricated restraining fixture

BOEING TOOLBOEING TOOL ALASKA AIRLINES TOOL

ALASKA AIRLINES TOOL