17.7 Flashcards
What must a propeller be protected against if it is to be stored?
Effects of corrosion, moisture and foreign debris ingress
Where are storage and removal from storage of serviceable and un serviceable installed propellers procedures found?
AMM
Where are the preservation and de preservation procedures located for unfitted propellers?
PMM
What are the storage periods for propellers?
3 months - short term
6 months - long term
12 months - long term
3 years - long term
What position should wooden propellers be stored in?
installed and un-installed
Wooden fixed pitch propellers should be placed in a horizontal position to ensure that there is even moisture distribution
What should you clean a wooden propeller with?
installed
They should be cleaned with a mild solution of soap and water and inspected for damage. Any deterioration
in the surface finish should be restored to prevent the ingress of moisture
What storage conditions should a wooden propeller be kept in?
(installed and un-installed)
The blades should be adequately ventilated and, if possible, the storage area should be clean, warm, dry, dark and well ventilated as well as free from
corrosive vapours. Ideal storage temperatures are between 10° C and 20° C
How should a metal propeller be stored?
installed
The procedure for metal fixed pitch propellers is similar to that of a wooden prop but with the addition of regular corrosion inspections
What must be done with a variable pitch propeller prior to shut down?
(installed)
The pitch control mechanism must be exercised to circulate the oil, then cleaned with mild soap and inspected for corrosion
If storing a prop for periods up to 6 months what must be done?
(installed)
The pitch change mechanism must be flushed with inhibiting oil and then covered in waxed paper, the external surfaces should be treated with lanolin, this must not be applied to de-icing boots
Props with metal blades should be stored how?
un-installed/assembled
Upright on stands where the hub is supported by a mandrel
How should a metal prop be treated to prevent corrosion?
un-installed/assembled
The external surfaces of the propeller should be coated with lanolin or an approved corrosion inhibitor
With short term storage of uninstalled props up to three months, what should be carried out?
(un-installed/assembled)
The pitch change mechanism should be drained
of oil and flushed with approved inhibiting oil. The pitch change mechanism surface should be coated in lanolin and the mechanism should be wrapped in waxed paper
With long term storage up to six months, an un-installed wooden propeller is stored the same as three months,
true or false?
(un-installed/assembled)
True
For metal, variable pitch propellers being store for up to six months, the procedure is the same as for short term storage up to three months, what is the exception?
(un-installed/assembled)
If the propeller blades have pre-loaded bearings, the blades must be rotated to prevent the bearings brinelling. This should be carried out at the six months
point
Explain the rotation of a metal blade with pre-loaded bearings
(un-installed/assembled)
The rotation procedure is carried out by marking the blade positions relative to their bearings prior to rotating each blade with an approved turning
paddle. The blade is turned through its full range of travel at least three times. While the rotation procedure is in progress, the blade should check for signs
of tightness or roughness. Oscillating the blade paddle should quickly relieve any initial friction. If there is any sign of roughness, the bearing should be
removed and inspected. If the check is satisfactory, the blade should be left at a position at least one
inch away from its original position
With storage up to 12 months the procedure is the same as three month and 6 month storage, except what?
(un-installed/assembled)
At twelve months , the bearings must
be removed and visually examined for signs of “brinelling” and corrosion. If satisfactory, the bearings must be cleaned, greased and reassembled on to
the blades. The propeller must then be re-inhibited and re-protected
Explain storage over 12 months
un-installed/assembled
The storage procedure remains similar to that of the three, six and twelve month examples. However, each year, the blades require exercising at the
six months and the nine months stage, followed by bearing removal and inspection at the twelve months point. The propeller will require re-inhibiting
at each twelve months point. At the three year stage the propeller must be sent for overhaul. The overhaul will include a hub/blade inspection as
required by AWN75
What are the long term storage periods for uninstalled and dismantled propellers?
Long term storage up to six months.
Long term storage up to twelve months.
Long term storage up to three years.
What is not required if a propeller is dismantled and remains in its original manufacturers
packing
it will not require re-inhibiting every twelve months
Blade bearings in a pre-loaded conditions require what?
They will still be subject to the requirement for exercising at the six month and nine month periods each year and the annual dismantling and inspection procedure
Providing that the propeller is in manufacturers packaging and has been exercised at the 6 and 9 month period, as well as the annual dismantling and inspection, how long can the prop be in storage before overhaul?
3 years
