[57机翼] SRM学习｜克鲁格襟翼裂纹放行标准和修复方法。

DESCRIPTION:

=====================

During the post-flight inspection of the datum aircraft at XXXX International Airport (XXX), deformation and one crack were found on the skin of 2# Krueger flap Ref/A/.

GUN has accomplished the inspections as following:

1.Did visual inspection of the damaged skin and adjacent structure parts.NO other damage was found.

2.Measured the size of the deformation, and the size was: 180mmx33mmx3mm (length X width x depth).

3.Measured the size of the crack, and the length of the crack was 180mm.

Please see the attachment Ref/B/ for the photos of the damage.

Please be noted there is no ability to repair the cracked flap in local. To accomplish a permanent repair, GUN propose to have a revenue flight from XXXX International Airport (XXX) to XXXX International Airport (XXX) with a temporary repair as following:

1.Drill stop-hole at each end of the crack.

2.Do a detail visual inspection of the stop-hole to make sure there is no more crack.

3.Fill and seal the deformation and crack with multiple layers of 3M-436 aluminum foil (speed tape) to restore the contour of the skin, and apply two layers of 3M-436 aluminum foil (speed tape) over the filled dented regions.

Please be noted that the aircraft is AOG, an 8 hours response will be apspanciated by GUN.

DESIRED ACTION:

======================

1. Please review and advise if the repair proposal is structurally acceptable as a temporary repair for one revenue flight on or before 8:00AM 2021/06/08(Beijing Time).

2. If 1 is negative, please provide your temporary repair suggestion.

3. Please provide a permanent repair plan follow on the temporary repair plan if possible.

RESPONSE:

Boeing has reviewed the Ref /A/ message and finds the proposed stop-drill and speed tape repair to be structurally acceptable with the following additional repair requirements:

1. Perform the stop-drill per Ref /C/ SRM, Para. 12. Ensure the distance between the outer edges of the stop-drilled holes does not exceed 6 inches.

2. Apply a chemical conversion coating to the bare surface of the aluminum parts per 737-800 SRM 51-20-01.

3. Apply a layer of BMS 10-79 Type III primer to the surface of the reworked area per SOPM 20-41-02.

This is a Time-Limited repair for 1 flight cycle.

Attached as Ref /D/ is the requested Repair and Deviation Record (RDR) for this time limited repair of one (1) flight cycle.

For permanent repair refer to 737-800 SRM 57-43-02-2R-3 (LE KRUEGER FLAP STRUCTURE - EXTERNAL REPAIRS).