AD 53-10-01

final rule

CURTISS-WRIGHT Model C-46 Series Aircraft

AD Number
53-10-01
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46A CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46D CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46F CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46R CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46E CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation C-46/CW20-T CURTISS-WRIGHT Model C-46 Series Aircraft
aircraft Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Aircraft Corporation | Skyways International Trading and Transport Co. | Tempo Design Corporation Super C-46/CW20-T CURTISS-WRIGHT Model C-46 Series Aircraft

Unsafe Condition

Excessive air temperatures and associated fire hazards in the vacuum system discharge line due to potential failure modes in the vacuum pump discharge port.

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

Required Actions

Install a fusible plug in the vacuum pump discharge port with specified AN 840-8D fitting and metal mixture, or install an equivalent oil separator with pressure relief valve. Incorporate recommended overboard drain line, fire-resistant hoses, and clamps if needed.

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

Compliance Time

not later than November 1, 1953

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

Affected Aircraft

Curtiss-Wright Model C-46 Series aircraft including C-46A, C-46D, C-46F, C-46R, C-46E, C-46/CW20-T, Super C-46/CW20-T models.

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

Federal Register Abstract

Vacuum Pump Discharge Port

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_53-10-01.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
53-10-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
CURTISS-WRIGHT Model C-46 Series Aircraft
Subject:
Vacuum Pump Discharge Port
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Air...Show more
Model:
C-46A | C-46D | C-46F | C-46R | C-46E | C-46/CW20-T | Super C-46/CW20-T
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: 53-10-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   53-10-01

SUBJECT HEADING:   CURTISS-WRIGHT Model C-46 Series Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   53-10-01 CURTISS-WRIGHT: Applies to all C-46 Series aircraft.

To be accomplished not later than November 1, 1953.

To guard against the possibility of excessive air temperatures and associated fire hazards in the vacuum system discharge line, one of the following modifications must be accomplished:

1. Install a fusible plug in the side of the vacuum pump discharge port at right angles to the axis of the discharge port boss. Some pumps incorporate a plugged hole in the discharge port which may be enlarged to a 3/8-inch pipe tapped hole to accommodate the fusible plug. This plug should employ an AN 840-8D fitting with a binary eutectic mixture of 67.8 percent tin and 32.2 percent cadmium, which has a melting point of 351 degrees F. A drawing describing the design of such a plug is shown in Figure Douglas 2. The 3/8-inch fusible plug fitting is intended for pumps such as the Model 3P-211. Brass fittings of the same design as the above dural fittings are also acceptable. Incorporation of an overboard drain line clamped to the fusible plug is recommended, but is not mandatory. On installations which do not use an overboard discharge line the possibility exists that the plug may damage other nacelle components if it can hit them upon being blown out of the adapter at high velocity. Therefore, if no overboard discharge line is provided, the installation must be made in such a manner that the plug will not be directed toward any vulnerable components when it is blown from the adapter.

Also, incorporation of steel lines with fire resistant hoses and utilizing hose liners and clamps in the vacuum discharge line is recommended if cracking and drying out of the flexible hose assemblies is experienced.

In lieu of this fusible plug installation:

2. An oil separator equivalent in principle to the Genisco No. 40081 incorporating a pressure relief valve which can be disassembled for cleaning must be provided. (Genisco Co. is located at 2233 Federal Ave., Los Angeles 64, Calif.)

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_53-10-01.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
53-10-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
CURTISS-WRIGHT Model C-46 Series Aircraft
Subject:
Vacuum Pump Discharge Port
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Airlift International, Inc. | Curtiss-Wright Corporation | Flying Tiger Line, Inc. | L. B. Smith Air...Show more
Model:
C-46A | C-46D | C-46F | C-46R | C-46E | C-46/CW20-T | Super C-46/CW20-T
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: 53-10-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   53-10-01

SUBJECT HEADING:   CURTISS-WRIGHT Model C-46 Series Aircraft

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   53-10-01 CURTISS-WRIGHT: Applies to all C-46 Series aircraft.

To be accomplished not later than November 1, 1953.

To guard against the possibility of excessive air temperatures and associated fire hazards in the vacuum system discharge line, one of the following modifications must be accomplished:

1. Install a fusible plug in the side of the vacuum pump discharge port at right angles to the axis of the discharge port boss. Some pumps incorporate a plugged hole in the discharge port which may be enlarged to a 3/8-inch pipe tapped hole to accommodate the fusible plug. This plug should employ an AN 840-8D fitting with a binary eutectic mixture of 67.8 percent tin and 32.2 percent cadmium, which has a melting point of 351 degrees F. A drawing describing the design of such a plug is shown in Figure Douglas 2. The 3/8-inch fusible plug fitting is intended for pumps such as the Model 3P-211. Brass fittings of the same design as the above dural fittings are also acceptable. Incorporation of an overboard drain line clamped to the fusible plug is recommended, but is not mandatory. On installations which do not use an overboard discharge line the possibility exists that the plug may damage other nacelle components if it can hit them upon being blown out of the adapter at high velocity. Therefore, if no overboard discharge line is provided, the installation must be made in such a manner that the plug will not be directed toward any vulnerable components when it is blown from the adapter.

Also, incorporation of steel lines with fire resistant hoses and utilizing hose liners and clamps in the vacuum discharge line is recommended if cracking and drying out of the flexible hose assemblies is experienced.

In lieu of this fusible plug installation:

2. An oil separator equivalent in principle to the Genisco No. 40081 incorporating a pressure relief valve which can be disassembled for cleaning must be provided. (Genisco Co. is located at 2233 Federal Ave., Los Angeles 64, Calif.)

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.

View Official Source ↗