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Hot work on aircraft, such as: heat shrink (M23053) or solder sleeve (M83519) installation is performed using only approved, intrinsically safe, explosion proof heat guns such as the HT- 900B or the MCH-100-A. Soldering is typically performed in controlled, shop (off aircraft) environments. This reduces the employment of hot work on fueled aircraft and improves the reliability of the termination. Affected harness or cable requiring soldering termination or repair should be removed from aircraft for soldering. However, there are few instances when soldering on aircraft is required, such as to solder center contacts of select RF connectors (e.g. MIL-DTL-39012).

The JSWAG has worked with Malcom Technologies to identify a safe solution for the on-aircraft soldering challenge. If operational requirements or component configuration require soldering be performed on aircraft, the MCH-116 soldering iron should be employed.   It is a portable attachment employed with the already approved MCH-100-A battery operated heat gun

The MCH-116 has been tested and meets the explosion proof (MIL-STD-810) and electromagnetic interference (MIL-STD-461) requirements. The MCH-116 plugs into the power supply of the Navy-fielded MCH-100-A using a quick disconnect plug. The 50 Watt soldering iron provides up to 4 hours of operation for typical soldering tasks. The kit comes with three different shaped replaceable tips (Figure 1) offering versatile application at temperatures between 595° and 1000° F depending on the tip employed. The soldering iron is expected to reach operating temperatures in 6-8 minutes. During suitability testing, it melted solder (Sn60Pb40) within two minutes. NSN (3439-01-536-6370) has been assigned and the joint service, general wiring maintenance manual update is awaiting publication in Change 3.

Before performing hot work on aircraft, specific authorization from Aviation Gas Free Engineer (AVGFE) or Gas Free Engineer (GFE) is required. Aircraft with open fuel cells, broken or open fuel lines must be certified gas free in accordance with NAVAIR 01-1A-35 or T.O. 1-1-3. Consult applicable platform-specific technical manuals for safety and operational requirements and also consult Cognizant Engineering Authority (CAE) for guidance before soldering. In some applications, crimped termination alternatives may provide superior performance to soldered terminations (MIL-STD-217). CAE may provide component substitution guidance such as upgrading a solder type to a crimped type connector.