AD 60-10-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Martin Corporation | 188A | LOCKHEED Model 188 Aircraft |
| aircraft | Lockheed Martin Corporation | 188C | LOCKHEED Model 188 Aircraft |
Unsafe Condition
The main float closure port of the fuel tank vent valve may remain closed due to slight pressure in the tank, and the pressure relief poppet in P/N 634056-1 tank vent valves may stick, both occurring at pressures less than the 1.75 p.s.i. setting.
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Required Actions
Drill a 1/8-inch hole in the suction relief flapper halfway between the center and the flapper seat, manually check the pressure relief poppet for free action, and complete these actions by the next periodic inspection.
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Compliance Time
As soon as possible but no later than the next periodic inspection
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Affected Aircraft
Lockheed Model 188A and 188C aircraft, all serial numbers
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Federal Register Abstract
Fuel Pressure Relief Valve
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_60-10-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 60-10-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 188 Aircraft Subject: Fuel Pressure Relief Valve Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Martin Corporation Model: 188A | 188C Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 60-10-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 60-10-05 SUBJECT HEADING: LOCKHEED Model 188 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 60-10-05 LOCKHEED: Amdt. 145 Part 507 Federal Register May 10, 1960. Applies to All Model 188 Aircraft. Compliance required as indicated. There have been reported instances of the main float closure port of the fuel tank vent valve remaining closed due to slight pressure in the tank. These pressures are considerably less than the 1.75 p.s.i. setting of the pressure relief poppet. There is also a possibility of sticking of the pressure relief poppet in the P/N 634056-1 tank vent valves. As a precautionary measure, underwing refueling must be accomplished with the overwing fuel caps removed until the following action has been taken. As soon as possible but no later than the next periodic inspection: (a) Drill a 1/8-inch hole in the suction relief flapper approximately halfway between the center of the flapper and the flapper seat. (b) Manually determine that the pressure relief poppet action is free. Upon accomplishment of above action normal underwing fueling procedures may be resumed. (Lockheed message to all Electra operators dated April 18, 1960, covers this same subject.) This airworthiness directive sent by telegram to all operators of 188 aircraft on April 19, 1960. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_60-10-05.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 60-10-05 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED Model 188 Aircraft Subject: Fuel Pressure Relief Valve Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Lockheed Martin Corporation Model: 188A | 188C 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: 60-10-05 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 60-10-05 SUBJECT HEADING: LOCKHEED Model 188 Aircraft ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 60-10-05 LOCKHEED: Amdt. 145 Part 507 Federal Register May 10, 1960. Applies to All Model 188 Aircraft. Compliance required as indicated. There have been reported instances of the main float closure port of the fuel tank vent valve remaining closed due to slight pressure in the tank. These pressures are considerably less than the 1.75 p.s.i. setting of the pressure relief poppet. There is also a possibility of sticking of the pressure relief poppet in the P/N 634056-1 tank vent valves. As a precautionary measure, underwing refueling must be accomplished with the overwing fuel caps removed until the following action has been taken. As soon as possible but no later than the next periodic inspection: (a) Drill a 1/8-inch hole in the suction relief flapper approximately halfway between the center of the flapper and the flapper seat. (b) Manually determine that the pressure relief poppet action is free. Upon accomplishment of above action normal underwing fueling procedures may be resumed. (Lockheed message to all Electra operators dated April 18, 1960, covers this same subject.) This airworthiness directive sent by telegram to all operators of 188 aircraft on April 19, 1960. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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