SERVICE LETTER ATR72 Original issue: J un 26/06Service Letter No. ATR72-52-6014 Page 1Copyright 2006 Avions de Transport Rgional - ATR - All rights reserved. Printed in France TITLE:ATR72 CARGO DOOR DOOR OUTER SKIN CRACK INDICATION DUE TO SHEAR FITTING. 1.EFFECTIVITY Valid all ATR72-102, ATR72-202, ATR72-212 and ATR72-212A. 2.REASON In the outer skin located underneath the cargo door hinge, cracks were found on someaircraft during NDT inspection asked by MRB task 52-31-04-1 or during Service BulletinNo. ATR72-52-1018 entitled: DOORS CARGO DOORS MODIFY FUSELAGE/DOORS HINGE embodiment. The aim of this Service Letter is: - To inform about possibility of crack detection. - To inform about possible reason of crack indication. - To recommend a specific inspection. 3.DESCRIPTION IN SERVICE EXPERIENCE As per inspection asked by MRB task 52-31-04-1, or during application of ServiceBulletin No. ATR72-52-1018, crack findings were reported on the cargo door skin. After analysis, it appears that these cracks are due to incorrect door operations, due to cargo door incorrect adjustment on the shear fitting area (Item 60 IPC 53-37-20 Figure 30). Several times, the shear fitting and the associated roller installed on the door showed wearing damage. This incorrect situation, together with the pressurization loads, introduces over-stress in the hinge area, and then, on cargo door external skin, at hinge to skin fasteners location. SERVICE LETTER ATR72 Original issue: J un 26/06Service Letter No. ATR72-52-6014 Page 2Copyright 2006 Avions de Transport Rgional - ATR - All rights reserved. Printed in France 4.RECOMMENDATION In order to avoid possible cracks on the cargo door skin, ATR recommends to pay particular attention to the shear fitting interface during cargo door adjustment as perAMM (J IC) 52-31-00 ADJ10000 (or during shear fitting reinstallation during Service BulletinNo. ATR72-58-1018 Part C embodiment). In addition, a Detailed Visual Inspection of the cargo door shear fitting area is strongly recommended at the first opportunity to verify if any abnormal wearing at the shear fitting location on fuselage side (Item 60 IPC 53-37-20 Figure 30) or at the roller shear fitting location on door side (Item 5 SRM ATR42 Chapter 52-31-20 Figure 101) is evidenced. Besides, it is also recommended to pay attention during the opening/closing operations of the door for any excessive effort or hard point, and therefore to perform the cargo door adjustment (AMM (J IC) 52-31-00 ADJ10000) as necessary.