JIG Fixtures; Replacement of Wing Attach Angles and Doublers on Douglas DC-3 Series Aircraft, Airworthiness Directive 66-18-2

AC 39-1A · FAA

Public domain · FAAAdvisory Circulars

Overview

The JIG Fixtures; Replacement of Wing Attach Angles and Doublers on Douglas DC-3 Series Aircraft, Airworthiness Directive 66-18-2 (AC 39-1A) is a public-domain FAA advisory circular, republished here as a free chaptered HTML edition with a linked table of contents and the official PDF.

Publisher: FAA
Document: AC 39-1A
Pages: 3

Key points

This advisory circular describes methods for ensuring that jig fixtures used in the replacement of wing attach angles and doublers on Douglas DC-3 series aircraft comply with Airworthiness Directive 66-18-2.
Douglas jig fixtures or equivalent fixtures designed for the installation of new heavier attach angles and doublers must be utilized for compliance with the AD.
Authorized personnel can determine if non-Douglas jig fixtures are equivalent, provided they have the necessary facilities and equipment for accuracy checks.
Jig fixtures must have a smooth vertical face and be rigidly constructed to maintain alignment during installation.
Jig fixtures should be carefully stored and checked for accuracy before each use to ensure continued reliable results.

Frequently asked questions

What is the purpose of this advisory circular?

The purpose of this advisory circular is to describe methods for determining that jig fixtures used in the replacement of wing attach angles and doublers on Douglas DC-3 series aircraft meet the requirements of Airworthiness Directive 66-18-2.

What types of jig fixtures are acceptable for compliance?

Douglas jig fixtures or their equivalents designed for the specific purpose of installing new heavier attach angles and doublers must be used for compliance with the AD.

Who can determine if a non-Douglas jig fixture is equivalent?

Authorized persons, including appropriately rated certificated mechanics, repair stations, air carriers, or commercial operators, can determine if non-Douglas jig fixtures are equivalent.

What should be checked on jig fixtures before use?

Jig fixtures should be checked to ensure that original accuracy has been retained and that they are free from damage before each use.

What is required for the vertical face of the jig fixture?

The vertical face of the jig fixture must be smooth and in a straight undeviating plane from leading to trailing edge and from top to bottom of the attach angle and doubler area.

Document

AC

D A V E :

A D V I S O R Y

C I R C U L A R

OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

JIG FIXTURES; REPLACEMENT OF WING ATTACH ANGLES SUBJECT: AND DOUBLERS ON DOUGLAS SERIES AIRCRAFT, AIRWORTHINESS DIRECTIVE 1 PURPOSE. This circular describes methods of determining that jig fixture s used in the replacement of the subject attach angles and doublers meet the requirements of Airworthiness Directive 2 . CANCELLATION. Advisory Circular dated is cancelled.

3 . GENERAL. AD specifies that Douglas jig fixtures, or their equival ent (that are designed and built for the specific purpose of installation of the new heavier attach angles and doublers on series aircraft), shall be utilized in the AD compliance.

4 ACTION . The use of jig fixtures in compliance with the AD .

is of utmost importance. The determination that satisfactory jigs are utilized may be accomplished in accordance with the following: a. Obtain jig fixtures, Douglas P/N and P/N or Douglas P/N and P/N manufactured by the Douglas Aircraft Company, or Jig fixtures of other manufacture may be forwarded to Douglas Aircraft Company for checking against master tooling, or Authorized persons (appropriately rated certificated mechanics, repair stations, air carriers, or commercial operators) complying with the AD may make the determination that jig fixtures are equivalent. For this purpose, facilities and equipment should be available for checking the accuracy of these fixtures, particularly in the following critical areas: AC Page 2 Fa The vertical face of the jig fixture ce Alignment.

- which will come in contact with the outer wing or center section attachment surfaces should be smooth and in a straight undeviating plane from leading to trailing edge and from top to bottom of the attach angle and doubler area.

R igidity . The jig should be of such rugged construction that, when bolted to the outer wing or center section for the purpose of installing replacement parts, it should not be possible to pull the jig fixture out of the straight plane alignment specified in above.

olthole Location. A Douglas manufactured template (which may be obtained from the Product Support Division of or an equivalent template should be used for determining bolt hole location.

5 . PRECAUTION. For continued accurate results, jig fixtures should be Prior to each carefully stored to avoid or other damage.

subsequent use, the jig fixtures should be checked to be sure that original accuracy has been retained.

Advisory Circular Feedback Form If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by contacting the Flight Standards Directives Management Officer at 9-AWA-AFS-140-Directives@faa.gov .

Subject: AC 39 - 1A , Jig Fixtures; Replacement of Wing Attach Angles and Doublers on Douglas DC-3 Series Aircraft, Airworthiness Directive 66-18-2 Date: _____________________ Please check all appropriate line items: An error (procedural or typographical) has been noted in paragraph ____________ on page _______.

Recommend paragraph _____________ on page __________ be changed as follows: ______________________________________________________________________ ______________________________________________________________________ In a future change to this AC, please cover the following subject: (Briefly describe what you want added.)

______________________________________________________________________ ______________________________________________________________________ Other comments: ______________________________________________________________________ ______________________________________________________________________ I would like to discuss the above. Please contact me.

Submitted by: Date: ______________________