AD 74-20-10

EMERGENCY AD emergency

Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series

AD Number
74-20-10
Status
emergency
Effective Date
Product Category
appliance
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Leigh Systems Emergency Locator Transmitter Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series
appliance Leigh Systems Emergency Locator Transmitter Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series

Unsafe Condition

Chemical corrosion may cause failure of the Emergency Locator Transmitter (ELT) to operate or result in inadvertent activation, jamming the emergency frequencies of 121.5 MHz and 243.0 MHz.

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

Required Actions

Conduct a visual inspection for corrosion per Leigh Systems' Service Bulletin No. 003A or approved equivalent. If no corrosion is found, verify ELT transmission compliance. If corrosion exists or transmission fails, replace with an approved serviceable unit or TSO-approved unit before next flight except for ferry flights under FAR 91.52(e)(2).

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

Compliance Time

Within the next 90 days and thereafter at each additional 60 day interval after the effective date of this Airworthiness Directive.

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

Affected Aircraft

Leigh Systems Emergency Locator Transmitter Sharc 7 Series, serial numbers all through 163500 equipped with lithium batteries.

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

Federal Register Abstract

Emergency Locator Transmitter

Applicability Source Text

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AD Final Rules - DRS_74-20-10.html
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AD Number:
74-20-10
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series
Subject:
Emergency Locator Transmitter
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/30/1977
Make:
Leigh Systems
Model:
Emergency Locator Transmitter
Product Type:
Appliance
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 74-20-10
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-3104

AD NUMBER:   74-20-10

SUBJECT HEADING:   Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series

ACTION:  

SUMMARY:  

DATES:   Effective December 30, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
74-20-10 LEIGH SYSTEMS: Amendment 39-1976 as amended by Amendment 39-2038, 39-2732, and 39-3000 is further amended by Amendment 39-3104. Emergency Locator Transmitter Leigh Systems Sharc 7 Series. Applies to all Leigh Systems Sharc 7 Emergency Locator Transmitters Serial Numbers all through 163500 equipped with lithium batteries.

Compliance required as indicated.

As a result of chemical corrosion resulting in either failure of the Emergency Locator Transmitter (ELT) to operate or inadvertent activation, jamming the emergency frequencies of 121.5 MHz and 243.0 MHz accomplish the following:

Within the next 90 days and thereafter at each additional 60 day interval after the effective date of this Airworthiness Directive, accomplish the following:

1. Deleted.

2. Conduct a visual inspection for evidence of corrosion in accordance with photo reproduction which is part of Leigh System's Service Bulletin No. 003A, dated May 15, 1974, or equivalent inspections approved by Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

3. If no corrosion is found, prior to reinstalling, determine ELT transmits properly. ELT transmissions are authorized in the first five minutes of any hour or at other times if coordinated with the nearest FAA Tower or Flight Service Station for a total of three audio sweeps (Ref. FAA Advisory Circular 00-35A or 20-81).

4. If corrosion is found or if the ELT does not transmit properly, replace with an approved serviceable unit which has been inspected in accordance with paragraph 2; or replace with another TSO approved unit, prior to the next flight except that a ferry flight may be conducted in accordance with FAR 91.52(e)(2).

NOTE: ELT's equipped with lithium batteries may be identified by inspecting the identification tags. Units marked in the weight range of 1.5 to 2.0 lbs. are lithium batteries.

Amendment 39-1976 was effective October 1, 1974.

Amendment 39-2038 was effective December 9, 1974. Amendment 39-2732 was effective September 29, 1976.

Amendment 39-3000 was effective August 10, 1977.

This Amendment 39-3104 is effective December 30, 1977.








FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_74-20-10.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
74-20-10
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series
Subject:
Emergency Locator Transmitter
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/30/1977
Make:
Leigh Systems
Model:
Emergency Locator Transmitter
Product Type:
Appliance
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 74-20-10
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-3104

AD NUMBER:   74-20-10

SUBJECT HEADING:   Airworthiness Directives; LEIGH SYSTEMS: Emergency Locator Transmitter Leigh Systems Sharc 7 Series

ACTION:  

SUMMARY:  

DATES:   Effective December 30, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
74-20-10 LEIGH SYSTEMS: Amendment 39-1976 as amended by Amendment 39-2038, 39-2732, and 39-3000 is further amended by Amendment 39-3104. Emergency Locator Transmitter Leigh Systems Sharc 7 Series. Applies to all Leigh Systems Sharc 7 Emergency Locator Transmitters Serial Numbers all through 163500 equipped with lithium batteries.

Compliance required as indicated.

As a result of chemical corrosion resulting in either failure of the Emergency Locator Transmitter (ELT) to operate or inadvertent activation, jamming the emergency frequencies of 121.5 MHz and 243.0 MHz accomplish the following:

Within the next 90 days and thereafter at each additional 60 day interval after the effective date of this Airworthiness Directive, accomplish the following:

1. Deleted.

2. Conduct a visual inspection for evidence of corrosion in accordance with photo reproduction which is part of Leigh System's Service Bulletin No. 003A, dated May 15, 1974, or equivalent inspections approved by Chief, Engineering and Manufacturing Branch, FAA Eastern Region.

3. If no corrosion is found, prior to reinstalling, determine ELT transmits properly. ELT transmissions are authorized in the first five minutes of any hour or at other times if coordinated with the nearest FAA Tower or Flight Service Station for a total of three audio sweeps (Ref. FAA Advisory Circular 00-35A or 20-81).

4. If corrosion is found or if the ELT does not transmit properly, replace with an approved serviceable unit which has been inspected in accordance with paragraph 2; or replace with another TSO approved unit, prior to the next flight except that a ferry flight may be conducted in accordance with FAR 91.52(e)(2).

NOTE: ELT's equipped with lithium batteries may be identified by inspecting the identification tags. Units marked in the weight range of 1.5 to 2.0 lbs. are lithium batteries.

Amendment 39-1976 was effective October 1, 1974.

Amendment 39-2038 was effective December 9, 1974. Amendment 39-2732 was effective September 29, 1976.

Amendment 39-3000 was effective August 10, 1977.

This Amendment 39-3104 is effective December 30, 1977.








FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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