73-23-06 BEECH: Amdt. 39-1745. Applies to all Models A23-19, 19A, M19A and B19 (S/Ns MB-1 thru MB-557); and all Models 23, B23, and C23 (S/Ns M-1 thru M-554, M-1095 thru M-1415, M-1419, M-1423, M-1439 and M-1447) airplanes, having the vernier-type throttle control.
Compliance: Required as indicated, unless already accomplished.
To prevent throttle control actuating cable failure and loss of proper adjustment of the throttle control system, within 100 hours' time in service after the effective date of this AD, accomplish the following:
A) Inspect the throttle control cable in accordance with the following procedures:
1. Remove the engine cowling, disconnect the throttle control cable from the carburetor throttle arm, and remove the carburetor from the engine.
2. Move the throttle control through its full travel several times and check by feel for binding or roughness.
3. Lock the cockpit throttle control in the full forward position and apply approximately 50 lbs. pressure at the throttle cable rod end in a direction to force the control cable back into the housing. While this pressure is applied, mark the throttle control cable at the end of the housing.
4. Apply a pulling force of approximately 50 lbs. to the cable rod end and while this force is applied place another mark on the throttle control cable at the end of the housing.
5. If the throttle lock gives under either loading condition specified in Paragraphs A(3) and A(4) or if binding or roughness is evident during operation of the throttle control or if the distance between the marks made on the control cable in accordance with Paragraphs A(3) and A(4) is .25 inch or more, prior to further flight, replace the throttle control assembly with an airworthy assembly.
B) Replace the carburetor throttle shaft and stop arm assembly and throttle lever with either Marvel Schebler P/Ns 13-1521 and 12-B57 respectively and Marvel Schebler P/N 81- 311 nut if a MarvelSchebler Model MA-3-SPA carburetor is installed on the engine or Marvel Schebler P/Ns 13-1526 and 12-B56 respectively and Marvel Schebler P/N 81-311 nut if a Marvel Schebler Model HA-6 carburetor is installed on the engine.
NOTE: The Marvel Schebler carburetor modifications should be accomplished in accordance with instructions contained in the current Marvel Schebler Overhaul Manual.
C) Reinstall the carburetor and rig the throttle control cable to the throttle arm leaving a 1/16 inch cushion in the full throttle position as shown in Section 3 of Beechcraft Models 19, 23, and 24 Series Shop Manual, tighten Marvel Schebler P/N 81-311 nut to 25/60 in. lbs. torque and safety with a cotter pin.
D) Any equivalent methods of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.
Beechcraft Service Instructions No. 0589-159 or later FAA-approved revisions covers this subject.
This amendment becomes effectiveNovember 19, 1973.