# AD 48-33-01: Fuel System Placards

- Type: Airworthiness directive
- Status: Current
- Products: Lockheed 149-46, 49-46, 649-79 and 749-79
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 2 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/EB8BF1F25CBA52078625696D0071A63C.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/48-33-01

## The airworthiness directive

48-33-01 LOCKHEED: Applies to All 49-46, 149-46, 649-79 and 749-79 Models, Through Serial Number 2588.

Compliance with new placard restrictions required immediately. Placards to be installed not later than December 1, 1948.

Remove existing fuel placards and install three new placards covering fuel system operational procedure.

A. The placard to be removed from the 49-46 airplane is located on the Flight Engineer's lower instrument panel and reads: "CAUTION: Do Not Land With More Than 900 Gallons of Fuel in Each Outer Tank".

B. The placard to be removed from the 649 airplane is located on the Flight Engineer's uppermost panel and reads: "Fuel Load Restrictions Model 749. Takeoff: Do not Takeoff with Less Than the Following Fuel Loads":

The placards to be added read as follows:

1. "This Airplane Must be Fueled, and Fuel Used, in Accordance With the Charts in the Approved Operating Manual." (LAC, Part M302166).

2. "At All Times, Fuel in Tanks 2 and 3 Must Not Exceed Fuel in Tanks 1 and 4, Respectively." (LAC, Part M302163.)

3. "Fuel Transfer from one Tank to Another is not Permitted. When Operating the Fuel System on Crossfeed, the Tanks not Being Used Must be Turned Off." (LAC, Part M302109.)

(On Models 49-46, 149, 649, and 749 install placard 1 on Pilot's instrument panel and placards 1, 2, and 3, on Flight Engineer's uppermost instrument panel. Placard 3 has been installed on airplane Serial Number 2577 and subsequent, prior to delivery.

(LAC Service Bulletin 49/SB-439, dated March 23, 1948 covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-763](https://openairdocs.org/tcds/A-763): Lockheed Martin Aeronautics Company; names 4 of 6 models: 149-46, 649-79, 749-79, 49-46

## 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: 2 (2 by airframe model, 0 by engine model)
- Makers: Lockheed 2

Models with the most aircraft:

- [Lockheed 49-46](https://openairdocs.org/model/lockheed-49-46): 1 aircraft (airframe model)
- [Lockheed 749-79](https://openairdocs.org/model/lockheed-749-79): 1 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/48-33-01/models.md
Every aircraft: https://openairdocs.org/ad/48-33-01/aircraft.md

Its text cites no advisory circulars or STCs.

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