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XT 582 Maintenance Manual
Issue 1.0
September 21st 2005
Page 82
61.20.00 Blade Damage and Repair
The condition of a composite propeller is important for safe flight. The pilot of the aircraft needs to
check the condition of the propeller prior to each flight and ascertain its airworthiness. In general deep
scratches across the chord of the propeller are most significant, along with leading edge dents and
damage that may lead to delamination.
Leading edge damage is repairable as long as it is not larger than the specified sizes and that the
propeller is not delaminated. In general if the damage size on the surface of the propeller is not
exceeded then it will be better to leave the surface alone, as filling minor scratches will likely cause
more damage. The plys of the propeller are approximately 0.15mm thick each. If any doubts exist as to
the condition or repair procedure for the propeller either return the propeller to Airborne, or consult a
LAME engineer or equivalent who has experience with composite materials.
61.20.10 Balancing
Balancing of the propeller should not be necessary if the damage allowances are adhered to, repairs
should only be to replace what has been removed.
If there is any doubt or if propeller balancing is necessary it is best done by a person who is
experienced with composites and with Level 2 LAME qualifications or equivalent. An epoxy compatible,
clear spray paint applied at the tips is best, with the surface of the propeller prepared gently with 600
grade sandpaper, and cleaned to remove any oil residue.
61.20.20 Leading Edge Tape
Your propeller blade is supplied with a light grade of Urethane LE Protective Tape applied. This will
help resist the abrasive effects of dust, sand & water etc. It will not stop solid objects from damaging the
blade, although it will help reduce the damage. If the LE Tape is damaged, it has done its job and will
need replacing.
61.20.30 Damage Allowances
All propellers will eventually suffer damage from a variety of causes and in differing degrees of damage.
Varieties of damage such as water, stones, gravel & sand makes it very difficult to specify maximum
damage levels before the blade should be discarded rather than repaired. For a guide see the FAA
Advisory Circular AC 43.13-1B Par 8-71 through 8-109.
The design and construction (unlike wood, metal and many other composite props) is to progressively
increase strength from tip to root. As such a solid tip strike is not likely to destroy the hub or root of the
blade, (leading to a catastrophic failure), Damage is far more likely at the tip (as tip speed is much
higher) but less critical at the tip as it has less forces acting upon it (compared to the root / hub). As all
forces are focused on the root and hub sections – these areas are not to be damaged. If any doubt
exists as to the airworthiness of a propeller, have it properly assessed prior to flight.
61.20.40 Surface Scratches
The inner 250mm of the prop should not be damaged any further than minor nicks and scratches. This
is because it carries the most forces. This area is harder to damage than further out on the radius
because the speeds are lower. As a guide there should be no more than three scratches of 0.1mm
deep, and 25% of the chord in this area of a blade.
From 250mm out from the hub to the tip of the propeller the depth allowance is slightly greater at
0.15mm and extending a maximum of 25% of the chord. Slightly more damage is allowable toward the
tip. There should not be a concentration of scratches in one area.
61.20.50 Leading Edge Damage
Maximum allowed leading edge dent is 3mm within 250mm of the root to 8mm at the tip. The depth of
the dents allowable varies linearly from 250mm to 840mm (The Outer Diameter of the Propeller), the
equation for the allowable dent is as follows.
1. Measure the location from the prop hub (mm).
2. Depth = 3 + (0.00847 x (Location from Centre – 250)).
