# AD 47-34-01: Expansion Type Filler Cap

- Type: Airworthiness directive
- Status: Current
- Products: Textron D18C 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- Superseded by: Nothing supersedes this AD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/BABD941B0AF4FEA986256A1C0072E8A4.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/47-34-01

## The airworthiness directive

47-34-01 BEECH: (Was Mandatory Note 2 of AD-765-1.) Applies to D18C and D18S Airplanes Having Inside Filler Neck on 80-Gallon Nose Fuel Tanks.

Compliance required prior to November 1, 1947.

To prevent flight with the nose tank fuel cap off or unlocked, and to eliminate a fire hazard in the event of fuel tank or cap leakage, the following items are to be accomplished:

  (a) On tanks equipped with a cam type filler cap, install new filler neck, filler neck gasket, and screws suitable for use with the expansion type filler cap. (Tanks having an expansion type filler cap previously installed do not require this change.)

  (b) Replace the cam or expansion type filler cap with revised expansion type filler cap assembly, Beech P/N 404-189676.

  (c) Install a safety guard, Beech P/N 404-189689, on forward side of nose door cover plate in a manner to prevent closing the nose compartment door when the filler cap is not in place or locked.

  (d) Drill a 1/4-inch diameter hole in the lower skin of the nose compartment just forward of bulkhead No. 2 at the centerline of the airplane to provide drainage for the forward compartment under the fuel tank.

(Beech Service Bulletin D18-49 covers this same subject.)

## Affected data sheets (1) (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

## 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/47-34-01/models.md
Every aircraft: https://openairdocs.org/ad/47-34-01/aircraft.md

Its text cites no advisory circulars or STCs.

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