# AD 47-33-07: Alternate Static Source

- 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- Superseded by: Nothing supersedes this AD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/10C125BA809C32E986256A1C0072E7B4.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/47-33-07

## The airworthiness directive

47-33-07 BEECH: (Was Mandatory Note 2 of AD-770-1 and Mandatory Note 3 of AD- 765-1.) Applies to D18S, D18C and D18C-T Airplanes With Static Alternate Source Selector Valve.

Compliance required prior to October 15, 1947.

The present alternate static source does not comply with the Civil Air Regulations. The static selector valve should be removed and the AN 6270-4-22 flexible hose connected to the Beech 407-184756 static pressure tube by means of an 815-4D union.

(Beech Service Bulletin D18-47 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/47-33-07/models.md
Every aircraft: https://openairdocs.org/ad/47-33-07/aircraft.md

Its text cites no advisory circulars or STCs.

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