AD 61-16-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Brantly International, Inc. | B-2 | Airworthiness Directives; BRANTLY Model B-2 Helicopters |
| aircraft | Brantly International, Inc. | B-2A | Airworthiness Directives; BRANTLY Model B-2 Helicopters |
| aircraft | Brantly International, Inc. | B-2B | Airworthiness Directives; BRANTLY Model B-2 Helicopters |
Unsafe Condition
Failures of the right forward mount lug of the upper transmission case have occurred due to fatigue associated with undesirable pre-stress introduced during assembly procedures.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect and rework upper and lower surfaces of left and right forward transmission mount pads per specified procedures, including drilling, filing, and installing new brackets and bolts. Ensure proper fit of transmission bracket P/N B2-151-19 to avoid pre-stress.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 25 hours' time in service after the effective date of this directive
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Brantly International, Inc. Model B-2 helicopters prior to Serial Number 56 (excluding 16, 31, 44, 51, 52, 53) and prior to Serial Number 103 (excluding those with 0.375-inch thick mount lugs on P/N B2-104-2 upper transmission case)
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Transmission Mount Lug
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_61-16-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 61-16-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BRANTLY Model B-2 Helicopters Subject: Transmission Mount Lug Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/14/1961 Make: Brantly International, Inc. Model: B-2 | B-2A | B-2B Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 61-16-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 61-16-04 SUBJECT HEADING: Airworthiness Directives; BRANTLY Model B-2 Helicopters ACTION: SUMMARY: DATES: Effective August 14, 1961. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 61-16-04 BRANTLY: Amdt. 319 Part 507 Federal Register August 4, 1961. Applies to Model B-2 Helicopters as indicated. Compliance required within the next 25 hours' time in service after the effective date of this directive. Failures of the right forward mount lug of the upper transmission case have occurred on three Brantly B-2 helicopters. These failures are fatigue in nature and apparently are associated with an undesirable pre-stress in the mount lug introduced during assembly procedures. Since this condition is likely to exist in other such aircraft, it is necessary to require the following modifications: (a) Applies to all Model B-2 helicopters prior to Serial Number 56 except Serial Numbers 16, 31, 44, 51, 52, and 53. (1) Remove the main rotor and transmission and the three vertical control rods which protrude through the steel plate at the top of the forward firewall. (2) Rework the upper surface of the left and right forward transmission mount pads as follows: Insert a 5/16-inch diameter bolt downward through an AN 960-516 washer into the transmission mount bolt hole. File approximately 0.015 inch from the top surface of the mount pad except where protected by the washer. Remove bolt and washer. (3) Rework the lower surface of the left and right forward transmission mount pads as follows: Enlarge the lower 1/4 inch of the 5/16-inch diameter transmission mount bolt hole by drilling upward with a 21/64-inch drill. Use of a drill stop is strongly recommended to avoid exceeding the 1/4-inch depth of this rework. (4) Apply zinc chromate finish to reworked areas and reinstall transmission, rotor assembly, and control rods in accordance with Brantly Maintenance Manual procedures. (Brantly Service Bulletin No. 9 covers this same subject.) (b) Applies to all Model B-2 helicopters prior to Serial Number 103 except those with 0.375-inch thick mount lugs on P/N B2-104-2 upper transmission case. (1) Remove the NAS 145-22 bolt through the right forward transmission mount lug and the two AN 3-24A bolts through the upper transmission case (P/N B2-104-2) immediately inboard of the mount lug. (2) Install transmission bracket P/N B2-151-19 on top of the right forward transmission case mount lug and attach with new bolts and nuts through mating holes in transmission case previously exposed by (b) (1). These parts are furnished by Brantly Helicopter Corporation as their Modification Kit No. 20. (3) Insure a close fit of faying surfaces between the upper transmission case and bracket P/N B2-151-19 by accomplishing the following steps: Break sharp edges of the upper transmission case ledge to avoid interference with the inner radii of the new bracket; remove material from the upper transmission case ledge or from the lower surface of the bracket in contact with the case lug, as necessary. Failure to insure proper fit of this bracket will introduce undesirable pre-stress into the transmission mount lug. (Brantly Service Bulletin No. 14 covers this same subject.) This directive effective August 14, 1961. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_61-16-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 61-16-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BRANTLY Model B-2 Helicopters Subject: Transmission Mount Lug Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/14/1961 Make: Brantly International, Inc. Model: B-2 | B-2A | B-2B Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 61-16-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 61-16-04 SUBJECT HEADING: Airworthiness Directives; BRANTLY Model B-2 Helicopters ACTION: SUMMARY: DATES: Effective August 14, 1961. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 61-16-04 BRANTLY: Amdt. 319 Part 507 Federal Register August 4, 1961. Applies to Model B-2 Helicopters as indicated. Compliance required within the next 25 hours' time in service after the effective date of this directive. Failures of the right forward mount lug of the upper transmission case have occurred on three Brantly B-2 helicopters. These failures are fatigue in nature and apparently are associated with an undesirable pre-stress in the mount lug introduced during assembly procedures. Since this condition is likely to exist in other such aircraft, it is necessary to require the following modifications: (a) Applies to all Model B-2 helicopters prior to Serial Number 56 except Serial Numbers 16, 31, 44, 51, 52, and 53. (1) Remove the main rotor and transmission and the three vertical control rods which protrude through the steel plate at the top of the forward firewall. (2) Rework the upper surface of the left and right forward transmission mount pads as follows: Insert a 5/16-inch diameter bolt downward through an AN 960-516 washer into the transmission mount bolt hole. File approximately 0.015 inch from the top surface of the mount pad except where protected by the washer. Remove bolt and washer. (3) Rework the lower surface of the left and right forward transmission mount pads as follows: Enlarge the lower 1/4 inch of the 5/16-inch diameter transmission mount bolt hole by drilling upward with a 21/64-inch drill. Use of a drill stop is strongly recommended to avoid exceeding the 1/4-inch depth of this rework. (4) Apply zinc chromate finish to reworked areas and reinstall transmission, rotor assembly, and control rods in accordance with Brantly Maintenance Manual procedures. (Brantly Service Bulletin No. 9 covers this same subject.) (b) Applies to all Model B-2 helicopters prior to Serial Number 103 except those with 0.375-inch thick mount lugs on P/N B2-104-2 upper transmission case. (1) Remove the NAS 145-22 bolt through the right forward transmission mount lug and the two AN 3-24A bolts through the upper transmission case (P/N B2-104-2) immediately inboard of the mount lug. (2) Install transmission bracket P/N B2-151-19 on top of the right forward transmission case mount lug and attach with new bolts and nuts through mating holes in transmission case previously exposed by (b) (1). These parts are furnished by Brantly Helicopter Corporation as their Modification Kit No. 20. (3) Insure a close fit of faying surfaces between the upper transmission case and bracket P/N B2-151-19 by accomplishing the following steps: Break sharp edges of the upper transmission case ledge to avoid interference with the inner radii of the new bracket; remove material from the upper transmission case ledge or from the lower surface of the bracket in contact with the case lug, as necessary. Failure to insure proper fit of this bracket will introduce undesirable pre-stress into the transmission mount lug. (Brantly Service Bulletin No. 14 covers this same subject.) This directive effective August 14, 1961. 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.
Related Airworthiness Directives
2014-20-16
final ruleAirworthiness Directives; Brantly International, Inc. Helicopters
Unsafe Condition: Cracks or delamination in main rotor blades, particularly near the trailing edge, can lead to blade separation and loss of control.
2006-08-07
final ruleAirworthiness Directives; Brantly International, Inc. Model B-2, B-2A, and B-2B Helicopters
Unsafe Condition: Fatigue cracking of the vertical shaft, potentially caused by misalignment, leading to shaft failure and subsequent loss of control of the helicopter.
68-04-04 R2
final ruleAirworthiness Directives; BRANTLY Models B-2, B-2A, and B-2B Helicopters
Unsafe Condition: Failures of the tail rotor blade at the spar retention areas due to pitting corrosion and cracks detected through visual and dye penetrant inspections.
81-17-01
final ruleAirworthiness Directives; BENDIX: Applies to Bendix Starting Vibrator Assemblies, Part Numbers 10-176485-121, -122, -241, -242; 10-382780-12, -24
Unsafe Condition: Loss of ignition due to grounding of both 'P' (Primary) leads within the starting vibrator.