Many legacy Pilatus PC-12 aircraft continue to rely on the LITEF LCR-92/93 AHRS (Attitude and Heading Reference System), a technology that has delivered dependable service for decades. However, as these units age and support becomes increasingly limited, operators face a growing challenge: maintaining dispatch reliability without investing in a costly flight deck upgrade.
To address this issue, Archangel Systems completed an FAA-approved STC (Supplemental Type Certificate) that replaces the obsolete LCR-92/93 with a current-generation, solid-state AHRS solution designed specifically for the PC-12. Duncan Aviation supported the certification effort through installation and integration activities and is positioned to support installations throughout its network.
When introduced, the LCR-92/93 represented a significant advancement in aircraft attitude and heading technology. Its fiber optic gyro technology provided dependable performance, reduced maintenance requirements, and digital integration capabilities well suited for business aircraft.
The LCR-92 and LCR-93 have since become legacy products after LITEF discontinued production and introduced the newer LCR-100 family. Because the older units are no longer manufactured, repair support has become increasingly limited. Remaining repair options can be expensive and often involve long turnaround times, creating a significant supportability concern for operators and potentially increasing aircraft downtime when service is required.
This challenge affects a substantial portion of the PC-12 fleet. More than 700 legacy PC-12 aircraft are currently in operation worldwide, with more than 70% located in the United States. A significant number of these aircraft could potentially benefit from a practical replacement solution.
Archangel's replacement was developed specifically to address these challenges while minimizing installation complexity, aircraft downtime, and cost. The system replaces the LCR-92/93 with current-generation inertial sensing technology while preserving compatibility with the aircraft's existing avionics architecture.
The upgrade incorporates Archangel's AHR75 and AHR150 inertial sensing systems, magnetic sensing units, digital-to-analog converters, and a dedicated installation kit with adapter harnesses and mounting hardware. Adapter plates fit the existing LCR-92/93 mounting locations, while the adapter harnesses minimize wiring changes and eliminate the need for extensive cockpit, structural, or electrical modifications.
The AHR150A is currently flying under four Type Certificates spanning both fixed- and rotor-wing aircraft. The AHR75 is flying under one Type Certificate and is also used in U.S. Air Force surveillance aircraft. Derivative systems are also flying in supersonic aircraft worldwide.
Most installations can be completed in less than a week, providing one of the solution's key advantages: significantly reduced downtime and a quick return to service.
Compared with other upgrade options, the Archangel system offers a lower-cost alternative while maintaining the quality, accuracy, and performance operators expect from a modern AHRS solution. The AHR150A and AHR75 provide performance comparable to the LCR-92/93, as demonstrated through extensive flight testing, while replacing aging equipment with current-production, solid-state technology.
The system also maintains essentially the same installed weight, avoiding significant changes to aircraft weight or lever arms. It requires no periodic maintenance, and all components are TSO-approved and incorporate Level A software. The AHR150A also incorporates an RVSM-capable air data system that can support potential future avionics upgrades.
With this solution, Archangel offers a long-term support path built around current-production components and solid-state technology. Replacing aging equipment with a current-production platform can reduce long-term maintenance concerns while retaining compatibility with the aircraft's existing avionics suite.
The result is a practical AHRS replacement that can help extend the useful life of legacy PC-12 aircraft while minimizing cost, downtime, and operational disruption.
Duncan Aviation can perform installations at its Satellite Avionics Shops and MRO facilities, and it can also provide installation support at a customer's hangar when needed.
For more information about this Archangel solution, contact Duncan Aviation's Satellite Sales Manager.
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