AD 48-33-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Aircraft Corporation | 149-46 | LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 |
| aircraft | Lockheed Aircraft Corporation | 49-46 | LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 |
| aircraft | Lockheed Aircraft Corporation | 649-79 | LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 |
| aircraft | Lockheed Aircraft Corporation | 749-79 | LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 |
Unsafe Condition
Existing fuel placards may provide incorrect fuel load and transfer instructions, leading to improper fuel distribution and potential flight instability.
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Required Actions
Remove existing fuel placards and install three new placards specifying fuel system operational procedures, including fuel distribution limits and crossfeed operation restrictions.
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Compliance Time
Compliance with new placard restrictions required immediately. Placards to be installed not later than December 1, 1948.
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Affected Aircraft
Lockheed Models 49-46, 149-46, 649-79, and 749-79 through serial number 2588.
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Federal Register Abstract
Fuel System Placards
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-33-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-33-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 Subject: Fuel System Placards Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 149-46 | 49-46 | 649-79 | 749-79 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-33-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-33-01 SUBJECT HEADING: LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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.) FOOTER:
Document Text
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AD Final Rules - DRS_48-33-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-33-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 Subject: Fuel System Placards Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 149-46 | 49-46 | 649-79 | 749-79 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-33-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-33-01 SUBJECT HEADING: LOCKHEED Models 49-46, 149-46, 649-79, and 749-79 ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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