AD 84-09-51 R1
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Lockheed Martin Corporation | L-1011-385-1 | LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes |
| aircraft | Lockheed Martin Corporation | L-1011-385-1-14 | LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes |
| aircraft | Lockheed Martin Corporation | L-1011-385-1-15 | LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes |
| aircraft | Lockheed Martin Corporation | L-1011-385-3 | LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes |
Unsafe Condition
Depressurization of the aircraft due to failure of the negative pressure relief valve.
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Required Actions
Inspect the negative pressure relief valve mounting adapters within 100 flight hours. If cracks are found, replace or repair the adapter before next flight. Install specific stainless steel clips with required dimensions and fasteners for repairs or reinforcements. Repeat inspections at intervals not exceeding 25 landings or 500 landings depending on repair status, and comply with reinforcement requirements within 350 flight hours after last inspection or AD receipt.
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Compliance Time
Within 100 flight hours after the receipt of this AD
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Affected Aircraft
Lockheed Model L-1011-385 series airplanes, specifically serial numbers 1001 through 1250, and aircraft with replaced negative pressure relief valve adapters.
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Federal Register Abstract
Relief Valve Mount. Adap.
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_84-09-51_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 84-09-51 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes Subject: Relief Valve Mount. Adap. Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/11/1984 Make: Lockheed Martin Corporation Model: L-1011-385-1 | L-1011-385-1-14 | L-1011-385-1-15 | L-1011-385-3 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 84-09-51 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4903 AD NUMBER: 84-09-51 R1 SUBJECT HEADING: LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes ACTION: SUMMARY: DATES: Effective September 11, 1984. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 84-09-51 R1 LOCKHEED-CALIFORNIA COMPANY: Amendment 39-4903. Applies to Lockheed Model L-1011-385 series airplanes, certificated in all categories. Compliance required as indicated, unless previously accomplished. To prevent depressurization of the aircraft due to the failure of the negative pressure relief valve, accomplish the following: A. Within 100 flight hours after the receipt of this AD, unless previously accomplished, inspect the negative pressure relief valve mounting adapters on each aircraft identified as follows: 1. Lockheed Serial Numbers 1175 through 1250. 2. Lockheed Serial Numbers 1001 through 1174. Aircraft which have had either of the two negative pressure relief valve adapters replaced by the operator. B. Inspection and repair procedures: 1. After instituting all the preliminary safety precautions, gain access to aft side of the pressure bulkhead through fire bottle inspection panel 317 BB (see Lockheed Maintenance Manual MM6-40-00), and determine type of adapter installed. If adapter does not have circumferential spin marks and the serial number is 229 or lower, no further inspection is required. If serial number is 230 or higher, or spin marks are found, then additional inspection must be performed. NOTE: Adapter serial numbers are identified by the last three digits in the serial number block on the decal located at the 12 o'clock position aft of the pressure bulkhead. Spin marks are best determined by shining indirect light, such as flash light, on the adapter side wall. 2. On aircraft requiring further inspection: a. Gain access to the forward side of the negative pressure relief valve (see Lockheed Maintenance Manual MM25-42-00). b. On the forward side of the pressure bulkhead, LBL/RBL20, WL300, visually inspect the adapter part of each negative pressure relief valve in the area of the flange radius. Clean the area with solvent prior to inspection. 3. If a crack is found, replace or repair the adapter before the next flight. Replacement adapter must be inspected prior to installation and is subject to the requirements of this AD. 4. Installation of repair or reinforcement clips for adapter: Install 300 series stainless steel clips, either 0.050 1/4 hard or 0.040 1/2 hard material. Dimensions are 0.95-inch wide with 0.89 and 1.50-inch flanges, and 85 degrees bend, with 0.12-inch bend radius. Install clips using existing fastener holes through the aft pressure bulkhead and two additional fasteners through the side of the adapter, install one at minimum of 0.34 inches and the other at minimum of 0.95 inches from end of long leg of clip. Fasteners are to be MS20470AD5 rivets, or NAS1398M5 rivets, or structural equivalent. a. For repair of a cracked adapter, stop-drill crack 1/4-inch diameter, and install a minimum quantity of 40 clips per adapter, using 2 of each 3 attachments through the pressure bulkhead. b. For reinforcement of uncracked adapters, install a minimum quantity of 20 clips per adapter, using 1 of each 3 attachments through pressure bulkhead. 5. If no cracks are found, repeat the inspection per B.1. through B.4., above, at intervals not to exceed 25 landings. 6. Replace or reinforce the adapter within 350 flight hours after the last inspection or after the receipt of this AD, whichever is later. 7. With adapter reinforced with the 20 clips per paragraph B.4.b., above, the reinspection intervals may be extended from 25 landings to 1000 landings. 8. For adapters repaired with the 40 clips per paragraph B.4.a., above, reinspect from the aft side for cracks at the aft fastener, common to the clip and adapter, every 500 landings. 9. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. This amendment becomes effective September 11, 1984, and was effective earlier to those recipients of telegraphic AD T84-09-51, dated April 19, 1984. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_84-09-51_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 84-09-51 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes Subject: Relief Valve Mount. Adap. Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/11/1984 Make: Lockheed Martin Corporation Model: L-1011-385-1 | L-1011-385-1-14 | L-1011-385-1-15 | L-1011-385-3 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: 84-09-51 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4903 AD NUMBER: 84-09-51 R1 SUBJECT HEADING: LOCKHEED-CALIFORNIA COMPANY Model L-1011-385 Series Airplanes ACTION: SUMMARY: DATES: Effective September 11, 1984. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 84-09-51 R1 LOCKHEED-CALIFORNIA COMPANY: Amendment 39-4903. Applies to Lockheed Model L-1011-385 series airplanes, certificated in all categories. Compliance required as indicated, unless previously accomplished. To prevent depressurization of the aircraft due to the failure of the negative pressure relief valve, accomplish the following: A. Within 100 flight hours after the receipt of this AD, unless previously accomplished, inspect the negative pressure relief valve mounting adapters on each aircraft identified as follows: 1. Lockheed Serial Numbers 1175 through 1250. 2. Lockheed Serial Numbers 1001 through 1174. Aircraft which have had either of the two negative pressure relief valve adapters replaced by the operator. B. Inspection and repair procedures: 1. After instituting all the preliminary safety precautions, gain access to aft side of the pressure bulkhead through fire bottle inspection panel 317 BB (see Lockheed Maintenance Manual MM6-40-00), and determine type of adapter installed. If adapter does not have circumferential spin marks and the serial number is 229 or lower, no further inspection is required. If serial number is 230 or higher, or spin marks are found, then additional inspection must be performed. NOTE: Adapter serial numbers are identified by the last three digits in the serial number block on the decal located at the 12 o'clock position aft of the pressure bulkhead. Spin marks are best determined by shining indirect light, such as flash light, on the adapter side wall. 2. On aircraft requiring further inspection: a. Gain access to the forward side of the negative pressure relief valve (see Lockheed Maintenance Manual MM25-42-00). b. On the forward side of the pressure bulkhead, LBL/RBL20, WL300, visually inspect the adapter part of each negative pressure relief valve in the area of the flange radius. Clean the area with solvent prior to inspection. 3. If a crack is found, replace or repair the adapter before the next flight. Replacement adapter must be inspected prior to installation and is subject to the requirements of this AD. 4. Installation of repair or reinforcement clips for adapter: Install 300 series stainless steel clips, either 0.050 1/4 hard or 0.040 1/2 hard material. Dimensions are 0.95-inch wide with 0.89 and 1.50-inch flanges, and 85 degrees bend, with 0.12-inch bend radius. Install clips using existing fastener holes through the aft pressure bulkhead and two additional fasteners through the side of the adapter, install one at minimum of 0.34 inches and the other at minimum of 0.95 inches from end of long leg of clip. Fasteners are to be MS20470AD5 rivets, or NAS1398M5 rivets, or structural equivalent. a. For repair of a cracked adapter, stop-drill crack 1/4-inch diameter, and install a minimum quantity of 40 clips per adapter, using 2 of each 3 attachments through the pressure bulkhead. b. For reinforcement of uncracked adapters, install a minimum quantity of 20 clips per adapter, using 1 of each 3 attachments through pressure bulkhead. 5. If no cracks are found, repeat the inspection per B.1. through B.4., above, at intervals not to exceed 25 landings. 6. Replace or reinforce the adapter within 350 flight hours after the last inspection or after the receipt of this AD, whichever is later. 7. With adapter reinforced with the 20 clips per paragraph B.4.b., above, the reinspection intervals may be extended from 25 landings to 1000 landings. 8. For adapters repaired with the 40 clips per paragraph B.4.a., above, reinspect from the aft side for cracks at the aft fastener, common to the clip and adapter, every 500 landings. 9. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region. This amendment becomes effective September 11, 1984, and was effective earlier to those recipients of telegraphic AD T84-09-51, dated April 19, 1984. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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