FES Propeller Manual Version 1.11
November 2016
Page 9 of 10
2. At the 25 hours inspection (periodically to be done up to the annual inspection):
- clean the propeller with any car wash solution or equivalent.
- make the normal preflight inspection.
- inspect leading edge of the blades for minor paint damages from small stones.
Such minor damages can be easily repaired with small droplets of white acrylic paint.
When droplets of paint are dry, any excessive paint need to be carefully sanded so
that is in line with other surface. Only qualified persons are allowed to perform such
minor repair.
3. Annual inspection
- inspect propeller as per instructions given under point 2. If any crack is found in the
root section of propeller blades, they should be removed from service and send to the
manufacturer for inspection.
4. Service time between overhauls is 50 engine time running hours. At overhaul propeller
blades need to be inspected as per annual inspection. If there is more damages on the
paint than acceptable (see next section) propeller blades need to be repainted by qualified
person, with high quality white acrylic paint. Special care must be taken about equal
weight of the blades after repainting. Max acceptable difference is 0.3 grams.
8. Acceptable minor damages
1. No structural cracks or de-laminations of composite structure are allowed for the
propeller.
2. Thin cracks up to 10 mm of length in paint are allowed, but not in the root section. Only
in the outer part of the blade (15cm or more distance from attachment point) such cracks
in paint are acceptable. No sudden blade failure can occur due to such cracks. If such
cracks do occur, it is anyway advisable to consult with qualified service or manufacturer
regarding airworthiness. If is not clear please send a good photo and information about
operating time to FES producer.
3. Some erosion which occurs due to the peripheral speed of the blade and is normal.
However, always take care that the erosion never becomes so deep that FRP-coat is
damaged and there is a possibility that moisture may enter into the blade body. In this
case the blade must be repaired/overhauled immediately.
4. Stone damages. If stone damages are visible, mark them and check them periodically.
Maximum size of stone damages permitted for operation is 2x4 mm large and 0,7 mm
deep. Maximum number of damages allowed is one damage per 4 cm
2
. If bigger or more
damages exist on a blade, send propeller to manufacturer or qualified service for
inspection and overhaul.
5. Cracks or deformations in a center part of the propeller are not allowed. If such occurs,
send propeller back to manufacturer for the overhaul or replacement.
