The Rear Release Terminal Module (RRTM) is integral to the performance and maintainability of modern avionics systems. It enables safe, efficient, and serviceable electrical contact handling, especially suited for high-reliability aerospace environments. This guide provides an overview of RRTM’s features, specifications, and best practices for technicians.

Introduction

The Rear Release Terminal Module (RRTM) is a vital component in aircraft avionics systems. It ensures reliability, ease of maintenance, and efficient wire termination within circular or rectangular multi-pin connectors. This guide outlines its functionality, usage, and best practices.

Functional Overview of RRTM

RRTMs house crimped electrical contacts, securely retaining them within the connector body. Unlike front-release connectors that operate from the contact interface, rear-release systems operate from the wiring side. This configuration enhances maintainability and reduces the risk of wire damage.

Key Features

• Contact Retention Mechanism
• Ease of Maintenance
• Insertion/Extraction Tool Compatibility
• High-Density Capability
• Environmental and EMI Protection

RRTM Part Numbers and Specifications

A. Standard RRTM Modules

Part Number	Pin size	Type	Contact part number	Image
S280w555-102	16	(X) P	M39029/1-101
S280w555-104	16	(Y) Q	M39029/1-101
S280w555-108	16	(Z) U	M39029/1-101
S280w555-203	14	(V ) V	M39029/1-102
S280w555-206	14	(W) W	M39029/1-102

NOTE: All pins are crimped using AF8 and AFM8 and all pins are removed by a rear removal plastic tool as required.

B. High-Density RRTM Modules

Part Number	Pin size	Type	Contact part number	Image	Contact removal	Crimping
BACM15C3A	16	X	M39029/11-145		M81969/1-02 OR DHK21	AF8 OR AFM8
BACM15C3B	16	Y	M39029/11-145		M81969/1-02 OR DHK21	AF8 OR AFM8
BACM15C3C	16	Z	M39029/11-145		M81969/1-02 OR DHK21	AF8 OR AFM8
BACM15C1B		G	BACC47DE		DHK21	LH8

Repair Guidance

7.1 Repair in Unpressurized Areas

Repairs are performed using sealed configurations per SWPM 20-10-13 to prevent environmental factors like moisture or debris from affecting the wiring integrity.

7.2 Repair in Pressurized Areas

Use sealed configurations wherever possible. If not feasible, non-environmental splices that maintain electrical and mechanical integrity are acceptable.

7.3 Minor Damage Repairs

Use side-entry sleeves (BACS13DP-1 through -4) to restore and insulate damaged wires.

Technician Best Practices

• Always use OEM-specified tools and adhere to torque/insertion standards.
• Perform a ‘tug test’ to verify contact retention.
• Avoid excessive bending of wires near the module.
• Document all contact insertions/removals in maintenance logs.

Rear Release Terminal Modules (RRTMs) are foundational to the performance and serviceability of aircraft electrical systems. Their rear-serviceable design allows technicians to perform maintenance with minimal disruption, increasing system longevity and ensuring operational airworthiness.