AD 75-09-03

final rule

BOEING Model 707-100 and 720 Series Airplanes

AD Number
75-09-03
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft The Boeing Company 707-100 Long Body BOEING Model 707-100 and 720 Series Airplanes
aircraft The Boeing Company 707-100B Long Body BOEING Model 707-100 and 720 Series Airplanes
aircraft The Boeing Company 707-100B Short Body BOEING Model 707-100 and 720 Series Airplanes
aircraft The Boeing Company 720 Series BOEING Model 707-100 and 720 Series Airplanes
aircraft The Boeing Company 720B Series BOEING Model 707-100 and 720 Series Airplanes

Unsafe Condition

Cracks in the wing center section lower skin at the air conditioning duct anchor channel and air cycle machine support clip locations.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Visually inspect the wing center section lower skin for cracks at specified locations within 100 flights after the AD's effective date for airplanes with 20,000 or more flights. Repair cracked skins per Boeing's structural repair manual or approved method.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

within the next 100 flights after the effective date of this AD

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Boeing Model 707-100 and 720 series airplanes certificated in all categories, as noted in Boeing Alert Service Bulletin 3220.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Wing Center Section Lower Skin

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_75-09-03.html
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AD Number:
75-09-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
BOEING Model 707-100 and 720 Series Airplanes
Subject:
Wing Center Section Lower Skin
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
04/16/1975
Make:
The Boeing Company
Model:
707-100 Long Body | 707-100B Long Body | 707-100B Short Body | 720 Series | 720B 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Superseded AD: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Superseded By: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: 75-09-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2175

AD NUMBER:   75-09-03

SUBJECT HEADING:   BOEING Model 707-100 and 720 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective April 16, 1975.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-09-03 BOEING: Amendment 39-2175. Applies to all Boeing Model 707-100 and 720 series airplanes noted in Boeing Alert Service Bulletin 3220 certificated in all categories. Compliance required as indicated.
A. To detect wing center section lower skin cracks, within the next 100 flights after the effective date of this AD, for airplanes with 20,000 or more flights, visually inspect the wing center section lower skin for cracks at the air conditioning duct anchor channel just outboard of RBL 12.78 beam on stringer 17 and at the air cycle machine support clip just outboard of LBL 12.78 beam on stringer 18. Particular attention should be given to the wing skin at the forward and aft edges of the two support fittings.
B. Skins found cracking are to be repaired in accordance with the Boeing structural repair manual or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region.
C. This directive will be amended to require repetitive inspections when such have been determined.
D. For the purpose of complying with the Airworthiness Directive, subject to acceptance by the assigned FAA maintenance inspector, the number of flights may be determined by dividing each airplane's hours' time in-service by the operator's fleet average time from takeoff to landing for the airplane type. One flight is defined as one takeoff and landing.
The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1).
All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. The documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective April 16, 1975.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_75-09-03.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
75-09-03
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
BOEING Model 707-100 and 720 Series Airplanes
Subject:
Wing Center Section Lower Skin
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
04/16/1975
Make:
The Boeing Company
Model:
707-100 Long Body | 707-100B Long Body | 707-100B Short Body | 720 Series | 720B 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: 75-09-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2175

AD NUMBER:   75-09-03

SUBJECT HEADING:   BOEING Model 707-100 and 720 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective April 16, 1975.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
75-09-03 BOEING: Amendment 39-2175. Applies to all Boeing Model 707-100 and 720 series airplanes noted in Boeing Alert Service Bulletin 3220 certificated in all categories. Compliance required as indicated.
A. To detect wing center section lower skin cracks, within the next 100 flights after the effective date of this AD, for airplanes with 20,000 or more flights, visually inspect the wing center section lower skin for cracks at the air conditioning duct anchor channel just outboard of RBL 12.78 beam on stringer 17 and at the air cycle machine support clip just outboard of LBL 12.78 beam on stringer 18. Particular attention should be given to the wing skin at the forward and aft edges of the two support fittings.
B. Skins found cracking are to be repaired in accordance with the Boeing structural repair manual or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region.
C. This directive will be amended to require repetitive inspections when such have been determined.
D. For the purpose of complying with the Airworthiness Directive, subject to acceptance by the assigned FAA maintenance inspector, the number of flights may be determined by dividing each airplane's hours' time in-service by the operator's fleet average time from takeoff to landing for the airplane type. One flight is defined as one takeoff and landing.
The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1).
All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. The documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective April 16, 1975.

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.