AD 48-18-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Aircraft Corporation | 49-46 | LOCKHEED Model 49-46 Aircraft |
Unsafe Condition
Failure of the supercharger bearing thermocouple could result in unmonitored temperature of the rear supercharger universal coupling support bearing.
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Required Actions
Install a thermocouple on the cabin supercharger bevel gear housing and a direct reading indicator in the cockpit to monitor bearing temperatures.
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Compliance Time
prior to September 19, 1947
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Affected Aircraft
Lockheed Aircraft Corporation Model 49-46 Aircraft, serial numbers 1975 through 1980 and 2021 through 2088.
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Federal Register Abstract
Supercharger Bearing Thermocouple
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-18-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-18-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49-46 Aircraft Subject: Supercharger Bearing Thermocouple Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 49-46 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-18-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-18-04 SUBJECT HEADING: LOCKHEED Model 49-46 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-18-04 LOCKHEED: Applies to Model 49-46 Aircraft Serial Numbers 1975 Through 1980 and 2021 Through 2088. Compliance with the following was required prior to September 19, 1947, by direct notification of operators. Add thermocouple to cabin supercharger bevel gear housing, and direct reading indicator in cockpit to record temperatures of the rear supercharger universal coupling support bearing. (LAC Service Bulletin 49/SB-390 covers this same subject.) FOOTER:
Document Text
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AD Final Rules - DRS_48-18-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-18-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49-46 Aircraft Subject: Supercharger Bearing Thermocouple Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Aircraft Corporation Model: 49-46 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: 48-18-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-18-04 SUBJECT HEADING: LOCKHEED Model 49-46 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-18-04 LOCKHEED: Applies to Model 49-46 Aircraft Serial Numbers 1975 Through 1980 and 2021 Through 2088. Compliance with the following was required prior to September 19, 1947, by direct notification of operators. Add thermocouple to cabin supercharger bevel gear housing, and direct reading indicator in cockpit to record temperatures of the rear supercharger universal coupling support bearing. (LAC Service Bulletin 49/SB-390 covers this same subject.) FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
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