Aviation Parts Spotlight: The Arriel 1D1 & 2B Module Breakdown

Aviation Parts Spotlight: The Arriel 1D1 & 2B Module Breakdown


When it comes to high-performance helicopter operations, the Safran Arriel 1D1 and 2B engines remain industry standards for reliability, power, and endurance. Found in aircraft such as the Airbus AS350 series and EC130 models, these engines are trusted by operators across commercial, utility, firefighting, and military sectors worldwide. But what makes them tick? And more importantly—what do you need to know when maintaining or replacing critical components?


In this Aviation Parts Spotlight, we’re breaking down the Arriel 1D1 and 2B engine modules, explaining their function, common failure points, and how Black Mountain Aviation, an FAA-certified repair station in Boulder City, Nevada, supports operators with certified overhauls, inspections, and inventory solutions.

Safran Arriel helicopter engine module on test bench for inspection

Understanding the Arriel Engine Series


The Safran Arriel engine family has powered over 14,000 helicopters in 140 countries. Known for their simplicity, performance, and maintainability, the 1D1 and 2B variants are commonly installed in:


  • Airbus AS350 B2/B3 (H125)

  • Airbus EC130 B4 and T2

  • Other light and medium rotorcraft

Each Arriel engine is modular, consisting of five interchangeable primary modules and several secondary assemblies. This design allows for efficient overhauls and quicker service cycles.


Arriel 1D1 & 2B Module Overview


Let’s break down each module, highlighting key part numbers, functionality, and service insights.


Module 1: Transmission Shaft & Reduction Gear


  • Function: Transfers engine power to the main gearbox

  • Common Issues: Wear at the splines, bearing fatigue, vibration

  • 1D1 Part Number: 70BM015420

  • 2B Part Number: 70BM012000

Our Process:
We perform precision inspections of shaft alignment, spline engagement, and gear lash. Any signs of surface fatigue or wear result in immediate removal and replacement with FAA-certified parts.


Module 2: Axial Compressor


  • Function: Compresses incoming air for combustion

  • Common Issues: Foreign object damage (FOD), blade erosion, rotor imbalance

  • 1D1 Part Number: 70BM025020

  • 2B Part Number: 70BM022010

Our Process:
Modules are dismantled and checked for axial play and blade integrity. We use OEM specifications to re-balance rotors and verify proper airflow capacity.


Module 3: Gas Generator Turbine (Hot Section)


  • Function: Converts compressed air and fuel into rotational energy

  • Common Issues: Thermal cracking, turbine blade distress, tip erosion

  • 1D1 Part Number: 70BM035420

  • 2B Part Number: 70BM032020

Why It Matters:
Module 3 failures are among the most common in high-usage environments. We stock multiple M03 units in exchange to minimize downtime for operators who fly daily missions.


Module 4: Free Turbine


  • Function: Extracts energy from the combustion gases to drive the output shaft

  • Common Issues: Blade stretch, thermal fatigue, loss of turbine efficiency

  • 1D1 Part Number: 70BM045410

  • 2B Part Number: 70BM041720

Our Process:
We perform blade dimensional inspections, test rotational resistance, and replace bearings where necessary. All overhauled modules include complete logbooks and FAA 8130-3 forms.


Module 5: Accessory Gearbox


  • Function: Drives the fuel control unit, starter-generator, and other accessories

  • Common Issues: Gear slippage, cracked casings, oil seal leaks

  • 1D1 Part Number: 70BM055420

  • 2B Part Number: 70BM052000

Why It’s Critical:
A faulty accessory gearbox can compromise engine start-up, fuel regulation, and even electrical power delivery. Our team performs in-depth bench testing and gear timing verification before any reinstallation.


Additional Arriel Engine Components


In addition to the five core modules, Black Mountain Aviation stocks and services key secondary components:


  • Freewheel Shaft Assembly: 1D1 – 0292907680 | 2B – 0292900020

  • Fuel Control Unit (HMU): 1D1 – 0164851320 | 2B – 0292861650

  • Start Drain Valve: 0174078030

  • Overspeed Drain Valve: 0174120180

  • Pump and Metering Valve: 2B1 – 0292862620

  • Epicyclic Gearbox: 350A32-0120-00

Each part is critical to the operation, safety, and compliance of the engine system. Whether your issue is performance-related or compliance-driven, we have the expertise and inventory to resolve it.


How We Support Arriel Engine Operators


At Black Mountain Aviation, we do more than supply Arriel modules—we support your mission end-to-end.


1. FAA-Certified Overhaul & Exchange


All modules are serviced under our FAA Repair Station Certificate LVBR789X using OEM specifications, specialized tooling, and calibrated equipment.


We offer:

  • Complete module exchanges for rapid turnaround

  • On-site testing and certification

  • Full traceability and documentation (8130-3)

2. Comprehensive Inventory


We maintain one of the largest selections of in-stock Arriel engine parts in Southern Nevada, including complete modules and individual components.


Our inventory covers:

  • Arriel 1D1 and 2B modules (M01–M05)

  • Swashplates, AVA assemblies, tail rotor spiders

  • Crossbeams and MGB parts for Airbus helicopters

3. Expert Diagnostics & Field Support

Our certified A&P mechanics can perform:


  • Borescope inspections

  • Hot section troubleshooting

  • Field removals and installations

  • On-site diagnostics at your hangar or in the field


Who This Supports

Our Arriel engine support services benefit:


  • Tour operators using AS350 B2/B3 and EC130 helicopters

  • Government and forestry contractors using helicopters for firefighting and aerial inspections

  • Charter fleets that require rapid turnarounds and FAA documentation

  • Independent pilots and private owners who want expert care without OEM delays


Why Choose Black Mountain Aviation?

Choosing a parts provider is about more than just availability. Here’s why operators across Nevada and the Southwest trust us:


  • Factory-trained technicians with decades of Arriel engine experience

  • Located at Boulder City Municipal Airport (KBVU) with hangar and FBO access

  • Satellite support in St. George, Utah and Maui, Hawaii

  • In-house avionics and rotorcraft maintenance for full-service support

We back every part with real-world knowledge, certified service, and transparent pricing.


Final Thoughts

Understanding your Arriel engine's modular design is key to smarter maintenance planning and operational readiness. From Module 1’s power transmission to Module 5’s accessory systems, each part plays a vital role in keeping your helicopter mission-ready.


At Black Mountain Aviation, we make it simple. Whether you're replacing a fuel control unit, troubleshooting a hot section issue, or seeking a quick module exchange, our FAA-certified team is here to help.


Contact us today at (702) 294-1044 or visit bmaviation.net to request availability or quote turnaround time.

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