AD 73-23-03

73-23-03 BEECH: Amdt. 39-1741. Applies to Models A23-19, 19A, M19A and B19 (Serial Numbers MB-1 thru MB-603); Models 23, A23, A23A, B23 and C23 (Serial Numbers M- 2 thru M-1476); and Models A23-24 and A-24 (Serial Numbers MA-2 thru MA-368) airplanes.

NOTE: 19 series (Serial Numbers 507 thru 603) airplanes, 23 series (Serial Numbers 1325 thru 1476) airplanes, and A23-24 (Serial Numbers 364 thru 368) airplanes were equipped with single wall ducts when delivered from the factory. These airplanes are included in the AD to assure that if double walled ducts were installed in the field, they are removed.

Compliance: Required as indicated, unless already accomplished.

To preclude separation of the inner liner and possible blockage of carburetor induction air flexible ducts which may cause partial or complete engine power loss, accomplish the following within 100 hours' time in service after the effective date of this AD.

A) Remove the engine cowl as necessary to expose the carburetor induction air flexible ducts and visually inspect these ducts to determine whether they are single wall (reinforcing wire exposed inside the duct) or double wall (reinforcing wire sandwiched between the duct material). If the installed ducts are single wall, no further action is required.

B) If the installed carburetor induction air flexible ducts are double wall, prior to further flight, replace them with single wall ducts of applicable Beech part numbers specified in Beechcraft Service Instructions No. 0566-241, or later FAA-approved revisions or equivalent field fabricated duct or any other modification approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

NOTE: Equivalent ducts may be fabricated in the field using BEMCO Part Number SW2WC duct material of the same diameter and length as the duct removed. This material is manufactured by BEMCO, Post Office Box 68, Centerton, Arkansas 72719.

This amendment becomes effective November 13, 1973.