AD 90-24-07

AD Final Rules - DRS_90-24-07.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
90-24-07
Document Type:
AD Final Rules
Docket Number:
90-ASW-10
Subject Heading:
Airworthiness Directives; MCDONNELL DOUGLAS HELICOPTER COMPANY (MDHC) Model 369D, 369E, and 369F/FF ...Show more
Subject:
Main Rotor Transmission Bolts
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
12/10/1990
Make:
MD Helicopters, Inc.
Model:
369D | 369E | 369F | 369FF
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Superseded AD: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Superseded By: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: 90-24-07
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   90-ASW-10

AMENDMENT:   39-6784

AD NUMBER:   90-24-07

SUBJECT HEADING:   Airworthiness Directives; MCDONNELL DOUGLAS HELICOPTER COMPANY (MDHC) Model 369D, 369E, and 369F/FF Series Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective December 10, 1990.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
90-24-07 MCDONNELL DOUGLAS HELICOPTER COMPANY (MDHC): Amendment 39-6784. Docket Number 90-ASW-10. Applicability: All MDHC Model 369D, 369E, and 369F/FF series helicopters certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent possible failure of the main rotor transmission drive assembly, which could result in loss of control of the helicopter, accomplish the following:

(a) Within the next 300 hours' time in service after the effective date of the AD or at the next annual inspection or the next time the transmission is removed, whichever occurs first, after the main rotor transmission is removed inspect the MS21250-04036 bolts which retain the debris cover, P/N 369D25174. Remove any bolts with the head inscription shown as unacceptable in Figure 1, and replace with MS21250-04038 bolts, which have a length of 2.887 plus/minus 0.010 inch.

NOTE: MDHC Service Information Notice (SIN) DN-166.1, EN-57.1, and SIN FN-45.1, dated March 14, 1990, or later revisions pertain to this subject.

(b) Inspect the thread protrusion of all bolts. Remove any bolt which does not protrude through the H14-4 nut for a length equivalent to two full threads (0.071 inch minimum), including the chamfer. Replace removed bolts with MS21250-04038 bolts. Torque the bolts to 50-70 inch pounds. Verify that the bolts protrude through the nut for a length equivalent to two full threads (0.071 inch minimum), including the chamfer. If more than four threads protrude through the nut, add AN960C416L or AN960C416 washers under the nut as required. Remove and reinstall parts in accordance with the manufacturer's instructions.

(c) Apply a white dot to the main transmission data plate to indicate that the transmission has been inspected and reworked in accordance with the manufacturer's instructions, and record compliance with this AD in the rotorcraft log book.

(d) In accordance with FAR Sections 21.197 and 21.199, flight is permitted to a base where the requirements of this AD may be accomplished.

(e) An alternate method of compliance or adjustment of the compliance time which provides an equivalent level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office, ANM-100L, FAA, Northwest Mountain Region, 3229 East Spring Street, Long Beach, California 90806-2425.

This amendment (39-6784, AD 90-24-07) becomes effective on December 10, 1990.



Figure 1. Inspection/Definition of Bolt Heads.

FOOTER: