AD 66-23-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 727-100 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-100C Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-200 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-200F Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727C Series | BOEING Model 727 Series Airplanes |
Unsafe Condition
B-nuts at the engine firewall, specifically part number NAS596, are susceptible to cracking due to being manufactured by AFCO (Aircraft Fitting, Inc.).
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Required Actions
Inspect the engine fuel feed system B-nuts using a 10-power glass, dye penetrant, or ultrasonic method. If cracks are found, replace the fuel line tube assembly with a new part per Boeing Service Bulletin 28-25. Repeat inspections every 600 hours' time in service until AFCO B-nuts are replaced within 3,000 hours' time in service after the AD's effective date.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 600 hours' time in service after the effective date of this AD
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Affected Aircraft
Boeing Model 727 Series airplanes listed in Boeing Service Bulletin 28-25, Revision 1, dated January 19, 1966.
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Federal Register Abstract
B-nuts at the Engine Firewall
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_66-23-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 66-23-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 727 Series Airplanes Subject: B-nuts at the Engine Firewall Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/16/1966 Make: The Boeing Company Model: 727-100 Series | 727-100C Series | 727-200 Series | 727-200F Series | 727 Series | 727C Series Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 66-23-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-288 AD NUMBER: 66-23-01 SUBJECT HEADING: BOEING Model 727 Series Airplanes ACTION: SUMMARY: DATES: Effective October 16, 1966. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 66-23-01 BOEING: Admit. 39-288 Part 39 Federal Register September 16, 1966. Applies to Model 727 Series Airplanes Listed in Boeing Service Bulletin 28-25, Revision 1, Dated January 19, 1966. Compliance required as indicated, unless already accomplished. It has been determined that certain of the B-nuts at the engine firewall on Boeing Model 727 Series airplanes are susceptible to cracking. To correct this condition: (a) Within the next 600 hours' time in service after the effective date of this AD, inspect the engine fuel feed system B-nut, P/N NAS596, located at each engine firewall to determine if it is an AFCO (Aircraft Fitting, Inc.) manufactured part. Identification must be made in accordance with the instructions listed in Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA-approved revision. (b) If the B-nut is not an AFCO part, no further action under this AD is required. If the B-nut is an AFCO part, accomplish the following before further flight: (1) Inspect for cracks using a 10-power glass, dye penetrant or ultrasonic method. (2) If cracks are found, remove the fuel line tube assembly and replace with a new part in accordance with Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA- approved revision or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. (3) If no cracks are found, repeat the inspection required under (1) every 600 hours' time in service until the AFCO B-nuts are replaced as specified in (c). (c) Within the next 3,000 hours' time in service after the effective date of this AD, unless already accomplished under (b), remove all fuel feed line tube assemblies incorporating AFCO B-nuts and replace in accordance with Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA-approved revision or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. (d) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection period of the operator if the request contains substantiating data to justify the increase for that operator. This directive effective October 16, 1966. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_66-23-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 66-23-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 727 Series Airplanes Subject: B-nuts at the Engine Firewall Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 10/16/1966 Make: The Boeing Company Model: 727-100 Series | 727-100C Series | 727-200 Series | 727-200F Series | 727 Series | 727C Series 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: 66-23-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-288 AD NUMBER: 66-23-01 SUBJECT HEADING: BOEING Model 727 Series Airplanes ACTION: SUMMARY: DATES: Effective October 16, 1966. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 66-23-01 BOEING: Admit. 39-288 Part 39 Federal Register September 16, 1966. Applies to Model 727 Series Airplanes Listed in Boeing Service Bulletin 28-25, Revision 1, Dated January 19, 1966. Compliance required as indicated, unless already accomplished. It has been determined that certain of the B-nuts at the engine firewall on Boeing Model 727 Series airplanes are susceptible to cracking. To correct this condition: (a) Within the next 600 hours' time in service after the effective date of this AD, inspect the engine fuel feed system B-nut, P/N NAS596, located at each engine firewall to determine if it is an AFCO (Aircraft Fitting, Inc.) manufactured part. Identification must be made in accordance with the instructions listed in Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA-approved revision. (b) If the B-nut is not an AFCO part, no further action under this AD is required. If the B-nut is an AFCO part, accomplish the following before further flight: (1) Inspect for cracks using a 10-power glass, dye penetrant or ultrasonic method. (2) If cracks are found, remove the fuel line tube assembly and replace with a new part in accordance with Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA- approved revision or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. (3) If no cracks are found, repeat the inspection required under (1) every 600 hours' time in service until the AFCO B-nuts are replaced as specified in (c). (c) Within the next 3,000 hours' time in service after the effective date of this AD, unless already accomplished under (b), remove all fuel feed line tube assemblies incorporating AFCO B-nuts and replace in accordance with Boeing Service Bulletin 28-25, dated December 3, 1965, or later FAA-approved revision or an equivalent approved by the Chief, Aircraft Engineering Division, FAA Western Region. (d) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection period of the operator if the request contains substantiating data to justify the increase for that operator. This directive effective October 16, 1966. FOOTER:
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Retrieved: Apr 8, 2026
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