SOW Attachment B_HC-144 Composite Repair ALC144512000 Drain Hole MOD.pdf

U.S. COAST GUARD

AVIATION LOGISTICS CENTER

ELIZABETH CITY, NC 27909

ALC ENGINEERING SPECIFICATION HC144512000.02

Subj: HC-144 CENTER WING TRAILING BOX DRAIN HOLES

1. PURPOSE.

The purpose of this engineering specification is to establish additional drain hole provisions to eliminate condensation pooling from cold-soaked fuel tanks.

2. CANCELLATION.

Not applicable

3. REFERENCE DOCUMENTS.

a. C-144 Aircraft Structural Repair Manual, CGTO 1 C-144A-3

b. General Advanced Composite Repair Processes Manual, TO 1-1-690

4. APPLICATION.

This engineering specification applies to all HC-144NB aircraft during Programmed Depot Maintenance (PDM) at ALC.

5. GENERAL INFORMATION.

During high altitude operations, fuel in the center and outer wing tanks will be cooled proportional to the time spent at high altitude and, upon landing at a warm climate location, will produce significant amounts of condensation on the associated exterior tank walls of zone 961 and 962 (center wing trailing edge). These areas are not ventilated, and repeated operations will allow for continued collection and pooling of condensation in the lowest point cavities. This pooled water is a significant contributor to the onset of corrosion. Installing one drain hole in each respective panel will significantly reduce pooling of condensation from sweating fuel tanks.

6. ACTION REQUIRED.

a. Remove panels 961AB, 9618B, 962AB, and 9628B.

b. Drill 8.5-mm holes IAW reference a., 51-42-20 and 51-70-39, or reference b., Chapter 4. (Refer to Figure 1 and Figure 2.)

c. Seal edges of all new holes IAW reference a. or reference b.

Stamp: ____________ _ Date: ______ _

**The division must ensure this QA is stamped and this documentation archived if the QA is not captured in another format (i.e., workbook, routing tag, or EAL).**

** Q.A. (1) REQUIRED AT THIS POINT**

d. Reinstall panels 961AB, 9618B, 962AB, and 9628B.

e. Make Significant Component History Report (SCHR) entry for work completed.

7. SUPPLY DATA.

Not applicable

8. LABOR HOURS REQUIRED.

2.5 hours

Distribution Statement D: Distribution authorized to the DHS/CG/DoD and their contractors for Administrative or Operational use, 28 MAY 2019.

Other requests shall be referred to Policy and QA

WARNING: This document contains technical data whose export is restricted by the Arms Export-Control Act (Title 22, U.S.C., Sec 2751, et.

seq.) or the Export Administration Act of 1979, as amended, Title 50, U.S.C. App 2401 et. seq. Violations of these export laws are subject to severe criminal penalties. Disseminate in accordance with provisions of DoD Directive 5230.25.

DESTRUCTION NOTICE: For classified documents, follow the procedures in DoD 5200.22-M, National Industrial Security Program Operating Manual, Section 5-705 or DoD 5200.1-R, Information Security Program Regulation, Chapter VI, Section 7. For unclassified, limited documents, destroy by any method that will prevent disclosure of contents or reconstruction of the document.

ALCES HC144512000.02 Page 1 of 2

SOW Attachment B

U.S. COAST GUARD

AVIATION LOGISTICS CENTER

ELIZABETH CITY, NC 27909

9. EFFECT ON WEIGHT AND BALANCE.

Not applicable

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