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Diamond Aircraft Industries
OPTIONAL SERVICE BULLETIN
Model DA 20-C1
DAC1-61-01 Rev. 5
Page 4 of 9
29 November 2019
I.7
Accomplishments/Instructions
PART I - Installation of W69EK7-63, W69EK7-63G, or W69EK7-63GM Propeller:
1. Remove the engine cowlings.
2. Remove the W69EK-63 propeller as per AMM Chapter 61.
3. Remove the six bushings in the propeller flange using the removal/installation tool as shown in
Figure 3.
4. Inspect the front spinner bulkhead and engine propeller adapter flange for fretting. If the fretting
is severe and cannot be dressed out with emery cloth and re-alodined, then the parts must be
replaced.
5. Clean the bushings and the bushing bores in the propeller adapter using denatured alcohol.
6. Install the new (7/16” ID) bushings into bores using Loctite 609 and the installation tool. Ensure
the bushings are completely pulled through the propeller flange. Reference Figure 3 for these
instructions.
7. Clean the propeller adapter flange (mating surface for propeller) with de-natured alcohol.
8. Clean the propeller hub faces with de-natured alcohol.
9. Install the W69EK7-63, W69EK7-63G, or W69EK7-63GM propeller in accordance with the
Sensenich Installation Manual (Doc. W69EK7-CF Rev. F, or later). If using AN7-47A bolts, install
AN960-716 or AN960-716L shim washers as necessary under the attachment nut to ensure 1-3
threads are showing above the nut. If using 22-6103-00-03 extended thread bolts, then it is
allowable if more than 3 threads are showing; AN960-716 or AN960-716L shim washers are not
required.
10. Follow the bolt torque check procedure specified in the Sensenich Installation Manual (Doc.
W69EK7-CF Rev. F, or later).
11. Record that this Service Bulletin has been accomplished in the aircraft’s maintenance logbook.
WARNING:
The hub of a wooden propeller will shrink or expand to match the ambient conditions.
Excessive hub shrinkage, especially possible during very cold and/or dry ambient conditions, can
result in the loss of propeller bolt torque (pre-load). This can allow slight movement relative to the
drive flange, which may result in damage to the propeller and/or the propeller bolts, and possibly
even the loss of the propeller. To prevent this, proper installation and periodic re-torquing in
accordance with all applicable maintenance instructions is necessary.
Under all circumstances, the inspection interval must never exceed 50 hours. Extreme changes in
ambient conditions (temperature/humidity) may require shorter inspection intervals.
