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


• 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


• 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)


• 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)



• 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


• Dial indicator can be difficult to read

• Dial indicator can be difficult to read


• Working conditions can be adverse

• Working conditions can be adverse


• 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


• Differences w/ Alaska Airline fabricated restraining fixture

• Differences w/ Alaska Airline fabricated restraining fixture

BOEING TOOLBOEING TOOL ALASKA AIRLINES TOOL

ALASKA AIRLINES TOOL

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

Documents

readthe end play check

adversethe end play

intervalthe end play

end play inspectionlubrication

timescheck end play

observationsdial indicator

acme nut fitting

procedureapply grease