# AD 47-33-06: Stabilizer Spar Replacement

- Type: Airworthiness directive
- Status: Current
- Products: Textron D18C, D18C-T and D18S
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Registered aircraft: 55 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/EA1103F399F2B28686256A1C00720FB0.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/47-33-06

## The airworthiness directive

47-33-06 BEECH: (Was Mandatory Note 1 of AD-770-1 and Mandatory Note 1 of AD- 765-1.) Applies to D18C, D18S and D18C-T Aircraft Serial Numbers AA-1 to AA-21, Inclusive, and AA-23 to AA-26, Inclusive.

Compliance required prior to November 1, 1947.

To eliminate the possibility of cracks developing in the stabilizer main spar and subspar, the center section of the main spar must be replaced with one having the lower flange-web radius cutout approximately 2 inches from either end. Two 0.064-inch dural channels (404-186053) should be installed between the new attachment fittings (437-186095 and 6) and the main spar web. At the main spar attachment fittings, an 0.032-inch dural doubler (404-186052) should be riveted to the lower skin, the main spar, and the center nose rib flanges.

The forward part of the upper flanges of each stabilizer-fuselage attaching angle should be cut off as far back as the sixth screw hole. The corresponding 12 holes in the stabilizer should beplugged. A three-screw outboard section of the gang nut on each side of the stabilizer subspar should be removed and the corresponding holes in the No. 13 bulkhead angle plugged. The revision of the stabilizer attachment eliminates the necessity for further inspection for cracks except as made during the normal periodic inspection.

(Beech Service Bulletin No. D18C-3 covers this same subject.)

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-765](https://openairdocs.org/tcds/A-765): Textron Aviation Inc.; names 2 of 17 models: D18S, D18C
- [TCDS TC 770](https://openairdocs.org/tcds/TC%20770): Hawker Beechcraft Corporation; names 1 of 2 models: D18C-T

## 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: 55 (55 by airframe model, 0 by engine model)
- Makers: Beech 55

Models with the most aircraft:

- [Beech D18S](https://openairdocs.org/model/beech-d18s): 55 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/47-33-06/models.md
Every aircraft: https://openairdocs.org/ad/47-33-06/aircraft.md

Its text cites no advisory circulars or STCs.

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