# AD 73-23-03: Flexible Induction Air Ducts - Type: Airworthiness directive - Status: Current - Products: Textron 19A, 23, A23, A23-19, A23-24, A23A, A24, B19, B23, C23 and M19A - Effective: November 13, 1973 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-1741 - Registered aircraft: 1,183 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FBDD61D7DC757CEF86256A080071CC2E.0001 - DRS record last changed: January 21, 2026 - Page: https://openairdocs.org/ad/73-23-03 ## The airworthiness directive 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. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A1CE](https://openairdocs.org/tcds/A1CE): Textron Aviation Inc.; names 11 of 14 models: A23-24, M19A, A24, A23, A23-19, B23, B19, 23… ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 1,183 (1,183 by airframe model, 0 by engine model) - Makers: Beech 1,183 Models with the most aircraft: - [Beech C23](https://openairdocs.org/model/beech-c23): 456 aircraft (airframe model) - [Beech 23](https://openairdocs.org/model/beech-23): 147 aircraft (airframe model) - [Beech B19](https://openairdocs.org/model/beech-b19): 145 aircraft (airframe model) - [Beech A23-24](https://openairdocs.org/model/beech-a23-24): 121 aircraft (airframe model) - [Beech A23](https://openairdocs.org/model/beech-a23): 85 aircraft (airframe model) - [Beech A23-19](https://openairdocs.org/model/beech-a23-19): 72 aircraft (airframe model) - [Beech B23](https://openairdocs.org/model/beech-b23): 62 aircraft (airframe model) - [Beech A23A](https://openairdocs.org/model/beech-a23a): 51 aircraft (airframe model) - [Beech 19A](https://openairdocs.org/model/beech-19a): 41 aircraft (airframe model) - [Beech B-19 SPORT](https://openairdocs.org/model/beech-b-19-sport): 2 aircraft (airframe model) - [Beech C 23](https://openairdocs.org/model/beech-c-23): 1 aircraft (airframe model) All 11 models: https://openairdocs.org/ad/73-23-03/models.md Every aircraft: https://openairdocs.org/ad/73-23-03/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.