HL70-6 - Bombardier Aerospace OEM Hilock Collar

HL70-6 – Bombardier OEM Hi-Lok® Collar (3/16", Aluminum)

Available now on the Airparts.aero Marketplace.

Overview

The HL70-6 is the collar component of a two-piece, high-strength Hi-Lok® structural fastening system, supplied with the full certification and traceability of Bombardier Aerospace as an Original Equipment Manufacturer (OEM) part. This is not a conventional nut; it is an advanced fastening component designed to be installed on a 3/16-inch diameter Hi-Lok® pin to create a joint with a precisely controlled and automatically verified clamp load (preload).

The defining engineering feature of the HL70-6 collar is its frangible, shear-off hex drive. During installation with specialized tooling, the collar is tightened until the design preload of the pin is achieved. At this precise point, the driving portion of the hex cleanly shears off, providing a simple, positive, and visual indication that the fastener is correctly installed. This technology removes operator variability and the need for torque wrenches, making it a cornerstone of modern, high-performance airframe assembly.

Key Features

• Bombardier OEM Certified: Guarantees the part is the factory-approved, fully traceable component for the Bombardier fleet, ensuring correct material and performance characteristics.

• Component of Hi-Lok® System: Designed to be paired with a corresponding -6 (3/16") diameter Hi-Lok® pin to form a complete, engineered fastening system.

• Controlled Preload Installation: The frangible hex drive is engineered to shear off at a predetermined torque, which induces the precise tensile preload in the pin for optimal joint strength and fatigue life.

• High-Strength Aluminum Alloy: Manufactured from 2024-T851 aluminum alloy, providing an exceptional strength-to-weight ratio ideal for primary airframe structures.

• Lightweight Structural Fastener: The Hi-Lok® system is significantly lighter than a traditional high-strength bolt and nut combination, contributing to overall aircraft weight savings.

• Anodized and Lubricated Finish: Anodized for corrosion resistance and typically coated with a solid film lubricant to ensure consistent torque-tension relationship during installation.

Technical Specifications

• Part Number: HL70-6

• Component Type: Hi-Lok® Fastening System Collar

• OEM Authority: Bombardier Aerospace

• Underlying Design Standard: LISI Aerospace Hi-Lok®

• Material: 2024-T851 Aluminum Alloy

• Finish: Anodized per MIL-A-8625, often with Cetyl Alcohol or Solid Film Lubricant.

• For Pin Diameter: 3/16 inch (.1875 inches)

• Thread Specification: Per Hi-Lok® standard for -6 pin.

Aircraft Compatibility

As a Bombardier OEM part, this Hi-Lok® collar is a specified structural fastener on their fleet of business and regional aircraft.

• Primary Bombardier Platforms:

  • Global Series (5000, 6000, 7500)

  • Challenger Series (300, 600 series)

  • CRJ Series Regional Jets

• General Aerospace Usage: The Hi-Lok® system is a primary fastening method used in the construction of most modern commercial, military, and business aircraft.

Note: Verification of applicability is the responsibility of the installer. Always consult the current version of the aircraft's Structural Repair Manual (SRM) to confirm part number eligibility for a specific location and repair scheme.

Applications

• Primary airframe structural assembly, including wing spars, ribs, and skin panel attachments.

• Fuselage frame and stringer construction.

• Landing gear trunnion and major component attachments.

• Pylon and engine mount structures.

• Any joint where a high-strength, lightweight, and consistently preloaded fastener is required.

Why Choose this HL70-6?

Hi-Lok® fasteners are flight-critical structural components where performance cannot be compromised. The precise shear-off torque of the HL70-6 collar is a key engineering feature of the joint's design. Using the genuine Bombardier OEM part is the only way to guarantee that the collar's material, heat treatment, and frangible hex are all precisely correct for the specific joint design on their aircraft. A non-certified part could have an incorrect shear value, which would result in a dangerously under-loaded (leading to fatigue failure) or over-loaded (leading to pin failure) joint, both of which are catastrophic failure modes.

The Hi-Lok® fastening system, featuring the HL70-6 collar, is an elegant solution to the challenge of achieving consistent preload in large-scale aircraft production and repair. The system's genius lies in its ability to isolate the critical preload variable from operator technique and tool calibration. The shear strength of the collar's frangible hex is a precisely controlled material property, engineered to correspond directly to the torque value that will induce the desired tensile stress (preload) in the mating pin. As the installation tool applies torque, the collar turns, stretching the pin elastically. Once the pin's elongation reaches the design point, the resistive torque in the joint equals the shear strength of the hex, and it cleanly shears off. This provides an automatic, positive stop, preventing over-torquing, and creates a uniform clamp load across thousands of fasteners, which is critical for distributing loads evenly in a structure and maximizing its fatigue life.

Applications

The HL70-6 collar is the specified component for creating permanent, high-strength structural joints:

• Fatigue-Critical Structures: The consistent preload achieved with the Hi-Lok system is essential for maximizing the fatigue life of a structural joint.
• High-Temperature Joints: Its primary application is in bolted joints that are exposed to significant heat, where it maintains its locking ability and strength.

Why Choose HL70-6?

The strength and reliability of an aircraft's structure is dependent on the integrity of its fastened joints. The Hi-Lok system, featuring the HL70-6 collar, provides a scientifically controlled method for achieving the correct clamp load, which is the most critical factor in a joint's performance. Using a genuine, traceable HL70-6 ensures you are installing a component with the certified material strength and precise engineering required to guarantee a safe, airworthy, and long-lasting structural connection, especially in high-temperature environments.

Order Your HL70-6 Hi-Lok Collars Now

Build and repair your aircraft structure with the precision and reliability of the Hi-Lok fastening system. Visit Airparts.aero to order your genuine HL70-6 collars today.

The Hi-Lok fastening system, which includes the HL70-6 collar, is a direct evolution of the traditional nut and bolt. It combines the benefits of a bolt and a rivet into one system. During installation, a special tool with a concentric sleeve holds the collar while an internal hex key passes through it to engage and hold the Hi-Lok pin stationary. As the tool tightens the collar, it stretches the pin, creating a high-preload clamping force on the structural members. When the preload reaches the designed value, the torque required to continue tightening exceeds the shear strength of the collar's thin-walled hex driver. This hex shears off cleanly, providing a visual indication of a completed installation and leaving behind a compact, permanent, and perfectly torqued collar.

Note: This is a flight-critical, single-use structural component. Once the hex drive has been sheared off, the collar cannot be reused. Installation requires specialized Hi-Lok® tooling (hex keys and sockets). It must be installed by a certified structures technician (A&P) in strict accordance with the aircraft's Structural Repair Manual (SRM). The sheared-off hex collars are considered Foreign Object Debris (FOD) and must be meticulously collected and accounted for after installation.

Documentation

Hi-Lok® design standards are proprietary to LISI Aerospace. All installation and repair procedures using this fastener are governed by the specific aircraft's Structural Repair Manual (SRM) provided by the airframe manufacturer (e.g., Bombardier).

• Common Aircraft Platforms:
  • Bombardier: Challenger, Global, and CRJ series
  • • Challenger 600
    • Challenger 601
    • Challenger 601-3A/3R
    • Challenger 604
    • Challenger 605
    • Challenger 650
    • Learjet 24
    • Learjet 25
    • Learjet 28
    • Learjet 29
    • Learjet 31
    • Learjet 35
    • Learjet 36
    • Learjet 55
    • Learjet 60 / 60XR
  • Textron Aviation Aircraft compatability:
  • • 1900 Airliner
    • 1900C Airliner
    • 1900D Airliner
    • Baron Series B55, E55, 58 or G58
    • Bonanza 36
    • Bonanza F33, G33, F33A or F33C
    • Caravan or Grand Caravan EX
    • Citation CJ1 or CJ1+
    • Citation CJ2 or CJ2+
    • Citation CJ3 or CJ3+
    • Citation CJ4
    • Citation III, VI or VII
    • Citation Latitude
    • Citation Longitude
    • Citation M2
    • Citation Mustang
    • Citation Sovereign or Sovereign+
    • Citation V, Ultra, Encore or Encore+
    • Citation X
    • Citation X+
    • Citation XLS, XLS+ or XLS Gen2
    • King Air 350 or 350C FM-1 to FM-35
    • Premier Model 390
    • SkyCourier
    • Stationair
  • Universally used by other major airframe manufacturers like Boeing, Airbus, and others.
• Common Applications:
  • Joining wing skins, spars, and ribs.
  • Assembling fuselage frames and bulkheads, particularly in firewall-forward sections.
  • Attaching primary structural brackets and fittings in high-temperature zones.