AD 48-18-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Aircraft Corporation | 49-46 | LOCKHEED Model 49-46 Aircraft |
Unsafe Condition
Cabin supercharger drive shafts may experience failure due to wear on the rear drive shaft universal joint, clutch end bearing, carbon oil seal, and overriding clutch, leading to potential oil seal damage and bearing failure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect cabin supercharger drive shafts every 300 hours of operation per LAC SB-107. Overhaul rear drive shaft universal joint, clutch end bearing, carbon oil seal, and overriding clutch. Replace defective parts and clutch end bearing 111GE regardless of condition. Replace sheet-metal retainer (P/N 257643) with bronze retainer (P/N 299449).
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
every 300 hours of operation
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Lockheed Aircraft Corporation Model 49-46 Aircraft
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Cabin Supercharger Driveshaft
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_48-18-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-18-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49-46 Aircraft Subject: Cabin Supercharger Driveshaft 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Make: Lockheed Aircraft Corporation Model: 49-46 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 48-18-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-18-03 SUBJECT HEADING: LOCKHEED Model 49-46 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-18-03 LOCKHEED: Applies to Model 49-46 Aircraft. Compliance required every 300 hours of operation. 1. Cabin supercharger drive shafts should be inspected at periods not to exceed 300 hours of operation in accordance with instructions and procedures specified in LAC Service Bulletin 49/SB-107, revised November 22, 1946. Concurrent with the foregoing inspection, the rear drive shaft universal joint, clutch end bearing, carbon oil seal and overriding clutch, should be completely overhauled. All defective parts are to be replaced and clutch end bearing 111GE is to be replaced regardless of condition. The sheet-metal retainer (LAC P/N 257643 is to be replaced as soon as practicable with bronze retainer (LAC P/N 299449). 2. The replacement of clutch end bearing 111GE will not be necessary if the supercharger is reworked to provide a double bearing support for the rear universal joint, and overrunning clutch assembly. This rework will also require replacing the present carbon faced oil seal with a slinger type and modify the supercharger housing to suit. The pre-flight inspections for oil seal damage can be dispensed with when slinger type seals have been installed. (LAC Service Bulletin 49/SB-393 covers this same subject.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_48-18-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 48-18-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 49-46 Aircraft Subject: Cabin Supercharger Driveshaft 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: 48-18-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 48-18-03 SUBJECT HEADING: LOCKHEED Model 49-46 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 48-18-03 LOCKHEED: Applies to Model 49-46 Aircraft. Compliance required every 300 hours of operation. 1. Cabin supercharger drive shafts should be inspected at periods not to exceed 300 hours of operation in accordance with instructions and procedures specified in LAC Service Bulletin 49/SB-107, revised November 22, 1946. Concurrent with the foregoing inspection, the rear drive shaft universal joint, clutch end bearing, carbon oil seal and overriding clutch, should be completely overhauled. All defective parts are to be replaced and clutch end bearing 111GE is to be replaced regardless of condition. The sheet-metal retainer (LAC P/N 257643 is to be replaced as soon as practicable with bronze retainer (LAC P/N 299449). 2. The replacement of clutch end bearing 111GE will not be necessary if the supercharger is reworked to provide a double bearing support for the rear universal joint, and overrunning clutch assembly. This rework will also require replacing the present carbon faced oil seal with a slinger type and modify the supercharger housing to suit. The pre-flight inspections for oil seal damage can be dispensed with when slinger type seals have been installed. (LAC Service Bulletin 49/SB-393 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.
Related Airworthiness Directives
93-14-12
final ruleAirworthiness Directives; ESSEX PB&R CORPORATION (formerly E.I. DuPont de Nemours and Company \\nIncorporated) PELS Model 4566M37B Crewmember Protective Breathing Equipment (PBE) Units
Unsafe Condition: Leakage of the PBE neck seal could compromise the crew's ability to combat an aircraft fire.
71-07-02
final ruleLOCKHEED Models 49, 149, 649, 749, 1049, and 1649 Series Airplanes
Unsafe Condition: Failure to provide an acceptable obstacle clearance profile when computing the takeoff flight path.
64-13-03
final ruleLOCKHEED Models 49, 149, 649, 649A, 749, 749A, 1049-54, 1049C, 1049D, 1049E, 1049G, and 1049H Series Aircraft
Unsafe Condition: Cracks and failure in the nose landing gear retract cylinder rod terminal ends (P/N 404052 or 1005032) due to fatigue.
64-07-04
final ruleLOCKHEED Models 49, 149, 649, 649A, 749, 749A, 1049-54, 1049C, 1049D, 1049E, 1049G and 1049H Series Aircraft
Unsafe Condition: Loose or unsafetied bolts in the parallelogram linkages of the primary flight control boost systems could result in loss of flight control system integrity.
