# AD 48-28-02: Cabin Heater Combustion Ducts

- Type: Airworthiness directive
- Status: Current
- Products: Boeing C54-DC, C54A-DC, C54B-DC, C54D-DC, C54E-DC, C54G-DC and DC-4
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 4 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/57F265618654D7F4862569BC005A9097.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/48-28-02

## The airworthiness directive

48-28-02 DOUGLAS: Applies to C-54 and DC-4 Aircraft.

To be accomplished not later than April 1, 1949.

As a fire protection measure in order to prevent burn through, replace the present cabin heater combustion ducts with corrosion resistant steel ducts.

(Douglas Service Bulletin DC-4 No. 89 covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-762](https://openairdocs.org/tcds/A-762): The Boeing Company; names 7 of 7 models: C54E-DC, C54G-DC, C54B-DC, DC-4, C54A-DC, C54D-DC, C54-DC

## 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: 4 (4 by airframe model, 0 by engine model)
- Makers: Douglas 4

Models with the most aircraft:

- [Douglas C54D-DC](https://openairdocs.org/model/douglas-c54d-dc): 2 aircraft (airframe model)
- [Douglas C54E-DC](https://openairdocs.org/model/douglas-c54e-dc): 1 aircraft (airframe model)
- [Douglas C54G-DC](https://openairdocs.org/model/douglas-c54g-dc): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/48-28-02/models.md
Every aircraft: https://openairdocs.org/ad/48-28-02/aircraft.md

Its text cites no advisory circulars or STCs.

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