AD 77-15-01

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AD Number:
77-15-01
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters
Subject:
Tail Rotor Drive System
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
07/28/1977
Make:
Airbus Helicopters Deutschland GmbH
Model:
BO-105A | BO-105C
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Superseded AD: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Superseded By: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: 77-15-01
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2970

AD NUMBER:   77-15-01

SUBJECT HEADING:   Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective July 28, 1977.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   77-15-01 MESSERSCHMITT-BOLKOW-BLOHM (MBB): Amendment 39-2970. Applies to Model BO-105A and BO-105C Helicopters, certificated in all categories, except those incorporating tail-rotor shaft bearing bracket, P/N 105-30251.40.
Compliance is required as indicated.
To prevent possible failure of the tail-rotor drive system, accomplish the following:
(a) Within the next 5 hours time in service after the effective date of this AD, remove the tail-rotor shaft fairings and visually inspect the tail boom skin for cracks in the vicinity of the three bearing brackets, P/N 105-30251.17, .18, and .19.
(b) If no crack is found during the inspection required by paragraph (a) of this AD, repeat the inspection at intervals not to exceed 50 hours time in service since the last inspection.
(c) If during any inspection required by this AD, one or more skin cracks at any of the three bearing brackets are found, comply with paragraphs (1) or (2) of this paragraph, as appropriate:
(1) If not more than one crack is found at any bracket and no crack is found to exceed 10 mm (0.4 in.) in length, stop-drill the cracks with a 4 mm diameter drill, and repeat the inspections specified in paragraph (a) of this AD at intervals not to exceed 10 hours time in service since the last inspection. If during any inspection required by this AD, any crack is found to have propagated beyond the stop-drill hole or to exceed 10 mm (0.4 in) in length, comply with paragraph (2) of this paragraph, prior to further flight, except as provided in paragraph (d) of this AD.
(2) If more than one crack is found at any bracket, prior to further flight, accomplish Subparagraph 2B2 of MBB Alert Service Bulletin No. 15, dated November 12, 1976, or an FAA-approved equivalent, and repeat the inspections specified in paragraph (a) of this AD at intervals not to exceed 10 hours time in service since the last inspection.
(d) The helicopter may be flown under the provisions of FAR 21.197 and 21.199 to a base where the repair can be performed, subject to the following conditions:
(1) Not more than one crack may exist at any bracket.
(2) The crack length at any one bracket may not exceed 50 mm (2 in.).
(3) Cracks may not exist on more than two brackets.
This amendment becomes effective July 28, 1977.

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