AD 79-10-06 R1
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Enstrom Helicopter Corporation, The | 280C | Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters |
| aircraft | Enstrom Helicopter Corporation, The | F-28C | Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters |
Unsafe Condition
Tail rotor blade grip cracks can cause tail rotor failures.
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Required Actions
Visually check tail rotor blade grips for cracks using a 10X glass before each flight. Perform dye penetrant inspection within 50 hours' time in service after the AD's effective date. Replace cracked grips with serviceable units (P/N 28-150013-1 or 28-150044-1) following Enstrom Service Directive 0048 or 0048 Rev A. Retorque close tolerance bolts with lubriplate compound.
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Compliance Time
Prior to next flight after receipt of this AD and prior to each flight thereafter; prior to the next 50 hours' time in service after the effective date of this AD.
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Affected Aircraft
Enstrom Helicopter Corporation Model F-28C and 280C helicopters.
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Federal Register Abstract
Tail Rotor Blade Grips
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_79-10-06_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-10-06 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters Subject: Tail Rotor Blade Grips Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 03/19/1982 Make: Enstrom Helicopter Corporation, The Model: 280C | F-28C Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 79-10-06 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4342 AD NUMBER: 79-10-06 R1 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters ACTION: SUMMARY: DATES: Effective March 19, 1982. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-10-06 R1 ENSTROM HELICOPTER CORPORATION: Amendment 39-3465 as amended by Amendment 39-4342. Applies to all Model F-28C and 280C helicopters. Compliance required as indicated. To prevent tail rotor failures as a result of tail rotor blade grip cracks, accomplish the following: A) Prior to next flight after receipt of this AD and prior to each flight thereafter, visually check the tail rotor blade grips in the vicinity of the blade retention bolt holes for any evidence of cracks with at least a 10X glass. Pilot may make this check. If any cracks are found, the blade and grip unit must be replaced with a serviceable unit before further flight. B) Prior to the next 50 hours' time in service after the effective date of this AD, unless already accomplished, remove the tail rotor blades from the blade grips and examine the grips in the vicinity of the blade retention bolt holes using standard dye penetrant inspection methods. Caution - care must be taken not to intermix blades and grips as they are match drilled sets. If any cracks are found, before further flight, remove the blade-and-grip unit and replace with a serviceable unit having either P/N 28-150013-1 or 28-150044-1 grips. Install replacement grips in accordance with paragraph C) of this AD. C) Install serviceable replacement P/N 28-150013-1 or P/N 28-150044-1 grips in accordance with applicable Enstrom Service Directive 0048, dated April 5, 1979, or 0048, Revision A, dated September 8, 1980, as outlined below: (1) Install P/N 28-150013-1 grips, in accordance with Enstrom Service Directive 0048, dated April 5, 1979, as follows: (a) By hand with the use of a 100 degrees - 1/2 inch back countersink (#AT4021-4) and a 3/16 inch pilot (#AT404-4), or equivalent tools, chamfer the edges (8 per grip) of the retention bolt holes in the blade grip .015 x 40 degrees. Repeat the same operation on each tail rotor blade retention bolt hole (4 places). After chamfering, thoroughly inspect the grips and blades for any nicks, burrs, or sharp edges. If any are found, they should be blended out by crocus cloth. (b) Replace the close tolerance bolts using a lubriplate compound and retorque to 50-75 in. lbs. (2) Install, P/N 28-150044-1 grips in accordance with Enstrom Service Directive 0048, Revision A, dated September 8, 1980, as follows: (a) Tail rotor assemblies incorporating Spindle P/N 28-150014-13 only are eligible for this alternate means of compliance. The part number is etched on the side of each spindle. Spindle P/N 28-150014-13 may be further identified by their shoulder-to-shoulder dimension and the rotor assembly's overall Tip-to-Tip length which are 3.46 + .01 and 56 7/16 inches, respectively. (b) Installation of Tail Rotor Blades on Tail Rotor Blade Grips P/N 28-150044-1 to comprise Blade and Grip Assemblies, P/N 28-150001-5 must be accomplished by Enstrom Customer Service. (c) Operators must send the old Tail Rotor Blade and Grip Assemblies P/N 28-150001-3 to Enstrom Customer Service Center for rework. D) Replace the close tolerance bolts using a lubriplate compound and retorque to 50 - 75 in. lbs. E) Preflight inspections required by paragraph A) of this AD may be discontinued after the installation of P/N 28-150044-1 grips. Enstrom Service Directive Bulletin No. 0048 also applies to the subject matter of this AD. Amendment 39-3465 became effective upon publication in the Federal Register, as to all persons except those to whom it was made immediately effective by the airmail letter dated April 9, 1979, which contained this amendment. This Amendment 39-4342 becomes effective March 19, 1982. FOOTER:
Document Text
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AD Final Rules - DRS_79-10-06_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-10-06 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters Subject: Tail Rotor Blade Grips Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 03/19/1982 Make: Enstrom Helicopter Corporation, The Model: 280C | F-28C 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: 79-10-06 R1 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4342 AD NUMBER: 79-10-06 R1 SUBJECT HEADING: Airworthiness Directives; Enstrom Model F-28C and 280C Helicopters ACTION: SUMMARY: DATES: Effective March 19, 1982. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-10-06 R1 ENSTROM HELICOPTER CORPORATION: Amendment 39-3465 as amended by Amendment 39-4342. Applies to all Model F-28C and 280C helicopters. Compliance required as indicated. To prevent tail rotor failures as a result of tail rotor blade grip cracks, accomplish the following: A) Prior to next flight after receipt of this AD and prior to each flight thereafter, visually check the tail rotor blade grips in the vicinity of the blade retention bolt holes for any evidence of cracks with at least a 10X glass. Pilot may make this check. If any cracks are found, the blade and grip unit must be replaced with a serviceable unit before further flight. B) Prior to the next 50 hours' time in service after the effective date of this AD, unless already accomplished, remove the tail rotor blades from the blade grips and examine the grips in the vicinity of the blade retention bolt holes using standard dye penetrant inspection methods. Caution - care must be taken not to intermix blades and grips as they are match drilled sets. If any cracks are found, before further flight, remove the blade-and-grip unit and replace with a serviceable unit having either P/N 28-150013-1 or 28-150044-1 grips. Install replacement grips in accordance with paragraph C) of this AD. C) Install serviceable replacement P/N 28-150013-1 or P/N 28-150044-1 grips in accordance with applicable Enstrom Service Directive 0048, dated April 5, 1979, or 0048, Revision A, dated September 8, 1980, as outlined below: (1) Install P/N 28-150013-1 grips, in accordance with Enstrom Service Directive 0048, dated April 5, 1979, as follows: (a) By hand with the use of a 100 degrees - 1/2 inch back countersink (#AT4021-4) and a 3/16 inch pilot (#AT404-4), or equivalent tools, chamfer the edges (8 per grip) of the retention bolt holes in the blade grip .015 x 40 degrees. Repeat the same operation on each tail rotor blade retention bolt hole (4 places). After chamfering, thoroughly inspect the grips and blades for any nicks, burrs, or sharp edges. If any are found, they should be blended out by crocus cloth. (b) Replace the close tolerance bolts using a lubriplate compound and retorque to 50-75 in. lbs. (2) Install, P/N 28-150044-1 grips in accordance with Enstrom Service Directive 0048, Revision A, dated September 8, 1980, as follows: (a) Tail rotor assemblies incorporating Spindle P/N 28-150014-13 only are eligible for this alternate means of compliance. The part number is etched on the side of each spindle. Spindle P/N 28-150014-13 may be further identified by their shoulder-to-shoulder dimension and the rotor assembly's overall Tip-to-Tip length which are 3.46 + .01 and 56 7/16 inches, respectively. (b) Installation of Tail Rotor Blades on Tail Rotor Blade Grips P/N 28-150044-1 to comprise Blade and Grip Assemblies, P/N 28-150001-5 must be accomplished by Enstrom Customer Service. (c) Operators must send the old Tail Rotor Blade and Grip Assemblies P/N 28-150001-3 to Enstrom Customer Service Center for rework. D) Replace the close tolerance bolts using a lubriplate compound and retorque to 50 - 75 in. lbs. E) Preflight inspections required by paragraph A) of this AD may be discontinued after the installation of P/N 28-150044-1 grips. Enstrom Service Directive Bulletin No. 0048 also applies to the subject matter of this AD. Amendment 39-3465 became effective upon publication in the Federal Register, as to all persons except those to whom it was made immediately effective by the airmail letter dated April 9, 1979, which contained this amendment. This Amendment 39-4342 becomes effective March 19, 1982. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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