AD 77-10-05

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AD Number:
77-10-05
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Bell Model 212 Helicopter
Subject:
Main Rotor Blades Skin Cracks
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/31/1977
Make:
Bell Helicopter Textron, Inc.
Model:
212
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Superseded AD: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Superseded By: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: 77-10-05
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2988

AD NUMBER:   77-10-05

SUBJECT HEADING:   Airworthiness Directives; Bell Model 212 Helicopter

ACTION:  

SUMMARY:  

DATES:   Effective August 31, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
77-10-05 BELL: Amendment 39-2893 as amended by Amendment 39-2988. Applies to Bell Model 212 helicopter certificated in all categories.

Compliance required as indicated.

To detect possible chordwise cracks in the main rotor blade skin from near the inboard end to near the outboard end and to detect eroded scarf joint filler, accomplish the following:

(a) Before the first flight of each day, after the effective date of this Airworthiness Directive, accomplish the following:

(1) Check the leading edge scarf joints of both main rotor blades for filler erosion.

(2) Clean and fill scarf joints having filler eroded to the metal, as specified in item 4 of Bell Helicopter Textron Service Bulletin No. 212-77-2 dated January 28, 1977, or later approved revision.

(3) Main rotor blades, P/N 204-012-001-33, and blades, P/N 204-012-001- 23 and -29, having serial numbers listed in Bell Service Bulletin No. 212-77-2 have an internal barrier behind the scarf joint and do not require the check in paragraph (a)(1) of this AD. Main rotor blades, P/N 204-012-001-23 and -29 that have external cover, P/N 204-015-011-1 or -701, installed in accordance with Bell Helicopter Textron Technical Bulletin No. 212-77-6 dated April 6, 1977, or later approved revision do not require the check in paragraph (a)(1) of this AD.

(b) For all Bell Model 212 helicopters having main rotor blades with 400 or more hours' total time in service on or after the effective date of this AD, accomplish either (1) or (2) of the following after the effective date of this AD:

(1) For main rotor blades not equipped with Blade Inspection System (BIS) or not equipped with a properly functioning BIS:
(i) Inspect the complete top and bottom surfaces of each main rotor blade before the first flight of each day and at intervals not to exceed 4 hours' time in service from the last inspection as specified in Part I, paragraph A, Bell Helicopter Textron Service Bulletin No. 212-75-6, Revision B, dated May 5, 1976, or later approved revisions.

(ii) Further flight is prohibited if a crack is found in the blade skin.

(2) For main rotor blades equipped with a properly functioning BIS that was factory installed, Blade P/N 212-012-001-33, or that was installed in accordance with the procedures and requirements of Bell Service Instruction No. 212-61, 204-32, or 205-45 dated August 13, 1976, or later approved revision:

(i) Check the blade inspection system by pressing the test button on the BIS detector located on the butt end of each blade before the first flight of each day and at intervals not to exceed 4 hours' time in service from the last check.

(ii) Further flight is prohibited if a steady light on the BIS detector occurs or if a crack in the blade is confirmed.

(iii) The affected main rotor blade may be returned to service after a visual inspection is conducted in which no cracks are found and after a flashing light occurs on the detector. (A flashing light indicates a closed or satisfactory circuit in the blade inspection system.)

(c) The checks in paragraph (a)(1) and (b)(2)(i) of this AD may be performed by the pilot.

Note: For the requirements regarding recording of compliance and method of compliance with this AD in the aircraft permanent maintenance record see FAR 91.173.

(d) Equivalent means of compliance with this AD may be approved by the Chief, Engineering and Manufacturing Branch, FAA, Southwest Region.

(e) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA, Southwest Region, may adjust the repetitive inspection intervals specified in paragraph (a) and (b) of this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

(f) The manufacturer's service bulletin and instruction identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to the Service Manager, Bell Helicopter Textron, P.O. Box 482, Fort Worth, Texas 76101. These documents may also be examined at the Office of the Regional Counsel, Southwest Region, FAA, 4400 Blue Mound Road, Fort Worth, Texas, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its headquarters in Washington, D.C., and at the Southwest Regional Office in Fort Worth, Texas.

(g) Within 300 hours' blade time in service, after August 31, 1977, and before using the BIS noted in paragraph (b)(2) of this AD, modify BIS installations on all main rotor blades, P/N 204-012-001-23 and -29, and blades P/N 204-012-001-33, S/N's A2-04012, A2-04037 through A2-04042, A2-04045, A2-04046, A2-04134 through A2-04138, A2-04347, A2-04359, A2-04387, A2-04389, A2-04397, A2-04398, A2-04404 through A2-04411, A2-04455, A2- 04457, AMR-04001 through AMR-04011, AMR-04013 through AMR-04015, AMR-04017 through AMR-04020, AMR-04023, AMR-04026, AMR-04030, and AMR-54001 through AMR- 54011 to comply with Revision 2 of Bell Service Instruction No. 212-61, 204-32, or 205-45, revision of March 28, 1977, or later approved revision.

NOTE: Bell Service Bulletin No. 212-77-10 lists these blades and serial numbers.

(h) This AD does not apply to Model 212 helicopters equipped with main rotor blades having P/N 212-015-501.

Amendment 39-2893 became effective June 12, 1977.
This amendment 39-2988 becomes effective August 31, 1977.

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