ESI-500 Electronic Standby Instrument

Why ESI-500

Acron Aviation’s ESI-500 Electronic Standby Instrument provides dependable safety redundancy for modern business aircraft, supplying critical attitude, airspeed, and altitude data on a clear, intuitive display whenever primary systems fail.

Solid-state sensors and an independent power architecture ensure essential flight information remains available during electrical or system disruptions, strengthening overall cockpit resilience.

Its compact, lightweight design consolidates multiple standby functions into a single unit, reducing panel clutter and saving valuable cockpit space. This integrated approach simplifies installation and maintenance while supporting cleaner avionics layouts for both new and retrofit aircraft.

With high reliability, fast startup, and consistent performance in varying conditions, our backup flight instrumentation reinforces the aircraft’s safety margin and gives pilots confidence that a trusted backup system is always ready to maintain situational awareness.

Backed by more than 60 years of proven reliability and its heritage, Acron Aviation delivers a legacy of precision and performance. Today, the company combines next-generation innovation with full legacy compatibility, enabling operators to modernize confidently while preserving trusted systems.

What this means for you

• Regulatory compliance and future-proofing: The ESI-500 meets modern standby instrumentation requirements and provides a flexible platform as standards evolve. Operators can maintain long-term compliance without frequent major upgrades, preserving aircraft value while supporting changing airspace and certification needs.
• Cost savings vs. legacy systems: By consolidating multiple mechanical instruments with a single integrated electronic unit, operators reduce maintenance frequency, spare-parts needs, and troubleshooting time. This streamlined approach lowers lifecycle costs while improving reliability, making it a practical replacement for aging standby equipment.
• Easy integration without rewiring: The ESI-500 is engineered to drop into existing avionics infrastructures with minimal disruption. By using current wiring and mounting provisions, it shortens installation time, reduces labor hours, and avoids expensive cockpit redesigns - allowing operators to upgrade quickly and efficiently.
• Operational efficiency and minimal downtime: Rapid installation and high system reliability keep aircraft mission-ready with fewer maintenance delays. Operators gain more predictable scheduling, reduced unscheduled ground time, and improved aircraft availability, ensuring consistent fleet utilization and revenue continuity.
• Risk mitigation and enhanced safety: Featuring an independent power source and robust solid-state sensors, the ESI-500 ensures critical flight data remains available during primary display failures. This dependable redundancy strengthens situational awareness, supports safer decision-making, and helps crews maintain control during unexpected events.

Regulatory compliance

The ESI-500 Electronic Standby Instrument is certified under multiple Federal Aviation Administration (FAA) Technical Standard Orders (TSOs), including TSO-C2d (airspeed instruments), C8e (vertical speed), C10b (pressure-sensitive altimeter), C34e, C35d, C36e, C40c, C46a, C106, C113a, C179a and C201.

ESI-500 is also accepted under European Union Aviation Safety Agency (EASA) via ETSO equivalency under the FAA–EASA Technical Implementation Procedures (TIP Rev 5), even though no separate ETSO marking is required.

The system’s software and hardware design adhere to the industry standards DO-178C (for software) and DO-254 (for electronic hardware), with Design Assurance Level C.

Approved Supplemental Type Certificates (STCs) and Approved Model List (AML) documentation exist for installation on many Part 23 light-airplane and Part 27 rotorcraft platforms.

Fleet compatibility

The ESI-500 is certified for installation under an Approved Model List (AML) Supplemental Type Certificate (STC) for a wide variety of aircraft - specifically covering Class I, II and III Part 23 fixed-wing airplanes and Part 27 helicopters.

Compatible aircraft manufacturers and models (representative examples) include light-aircraft and helicopter platforms such as: Grob G 120TP, Epic E1000, Quest Kodiak, MD Helicopter AH/MH‑6 Little Bird, and Airbus Helicopter H125 - among others listed under approved STCs.

For aircraft not already covered, the ESI-500 can often be installed via STC under AML for Part 23 fixed-wing and Part 27 rotor-craft platforms, subject to applicable certification paperwork, making it a versatile choice for many piston, turboprop, and light-helicopter fleets.

ESI-500 Solutions

Options are available for the display of navigation information and Synthetic Vision (SynVis), including terrain and obstacles. Magnetic heading is an available option when coupled with the low-cost and compact MAG-500 magnetometer. The ESI-500 is compatible with existing NAV radios and GPS hardware. Upon loss of power an internal lithium-ion battery pack automatically powers the unit and magnetometer without interruption.

Its compact “3-inch round case” design enables it to fit existing instrument panel cutouts - simplifying installation and avoiding the need for extensive panel rework.

Key capabilities

1. Display clarity and pilot situational awareness 

The ESI‑500 provides pilots with exceptional display clarity and enhanced situational awareness by using a high-resolution, full-color 24-bit display that presents critical flight data - attitude, altitude, airspeed, vertical speed, slip/skid, and aircraft track - in a crisp, easy-to-read format.

When optionally equipped with the system’s synthetic-vision (SynVis) mode, the ESI-500 overlays a 3-D representation of terrain, water, and obstacles, with terrain shading, water coloring, and gridlines to help pilots gauge distance and relative motion - making it easier to perceive terrain contours, obstacles, and ground features even in low-visibility conditions.

Additionally, when configured for navigation, the display can show VOR/ILS or GPS-derived navigation data (course deviation, vertical guidance, track information), offering a consolidated visual reference that reduces the need to scan multiple instruments - helping the pilot maintain better spatial and situational awareness throughout the flight. 

Overall, the ESI-500’s combination of crisp visuals, optional terrain/obstacle rendering, and integrated flight/navigation data gives pilots a coherent, intuitive “real-world plus instrumentation” view - improving decision making, reducing workload, and heightening safety.

2. Scalable capability with optional advanced features

The ESI-500 is engineered with a scalable architecture - it begins with core flight-data functions, but can be expanded with optional advanced capabilities as needs evolve.

At baseline, the ESI-500 delivers essential instrumentation: attitude, altitude, airspeed, vertical speed, slip/skid, and aircraft track. Beyond that, users can choose to enable navigation displays (VOR/ILS or GPS-based) - with course deviation, to/from indicators, vertical guidance (with ILS), and marker-beacon or GPS-track data per system configuration.

For enhanced situational awareness, the unit supports an optional synthetic-vision (SynVis) mode that overlays 3-D terrain and obstacle data - including terrain shading and obstacle alerts - when paired with GPS position, heading input (via optional MAG-500 magnetometer or ARINC-429 heading source), and appropriate terrain/obstacle databases.

In effect, the ESI-500 can serve as a simple standby instrument or scale up to a nearly full-featured multi-function display - offering flexibility so aircraft owners and pilots can tailor functionality to their budget, mission, and avionics architecture.

3. Reliable redundancy and independent backup power

The ESI-500 delivers robust redundancy and independent backup power as a core safety feature. Its built-in lithium-ion battery pack automatically takes over and powers the instrument - including attitude, airspeed, altitude, vertical speed, and slip/skid data (and optional heading via magnetometer) - in the event of a main-bus power failure.

The backup battery is designed to provide a minimum of one hour of uninterrupted operation under typical conditions (from –20 °C to +60 °C ambient) when properly maintained and charged. The battery system includes internal monitoring and safety circuits to prevent overcharging, deep discharge or thermal extremes that could compromise reliability.

By offering a dependable, self-contained backup power source, the ESI-500 ensures that critical flight data remains available even if the aircraft’s primary electrical system fails - making it a true reliable redundant standby instrument for piston, turboprop, or light-helicopter operations.

4. Seamless avionics integration and retrofit flexibility

The ESI-500 delivers true “seamless avionics integration and retrofit flexibility” by being designed to plug-into existing aircraft instrument and navigation systems - even older piston, turboprop or light-helicopter cockpits - without needing sweeping rewiring or major structural changes.

Specifically, the ESI-500 accepts standard ARINC 429 inputs (plus optional interfaces such as RS-485 for magnetometer data) so it can draw on existing NAV radios, GPS, or heading sources already installed on an aircraft. Its compact 3-inch round form factor is sized to fit into many existing panel cutouts - so you often don’t need to redesign the instrument panel to install it.

Moreover, the ESI-500 is scalable and configurable: Operators can choose whether to enable additional features such as navigation display, magnetic heading (when paired with the optional MAG-500), or full 3-D Synthetic Vision (terrain/obstacle display) - letting them customize the upgrade to match their budget, needs, and the existing avionics suite.

In the event of main-power loss, the unit’s built-in lithium-ion battery seamlessly kicks in, ensuring critical flight data remains available - an essential part of a retrofit solution where redundancy and reliability must be preserved even without a full glass-cockpit overhaul.

5. Compact, panel-friendly design

The ESI-500 is built to deliver a compact, panel-friendly design - ideal for both piston/turboprop airplanes and light helicopters.

Despite its advanced capabilities, the ESI-500 is small and light: It weighs roughly 2.1 lb. (nominal) and no more than 2.75 lb. at maximum, making it easy to integrate without heavy structural changes. Its display resides in a 3-inch round case, intentionally sized to slide into many existing instrument panel cut-outs - so installers often don’t need to redesign or widen the panel just to accommodate it.

Because of its modest size and shape, the ESI-500 adds much of the functionality of a modern electronic standby instrument - such as attitude, altitude, airspeed, vertical speed, slip/skid, plus optional navigation, synthetic-vision terrain/obstacle displays and heading (with optional magnetometer) - while occupying minimal panel real estate.

The ESI-500’s compact form factor and conventional 3″-gauge footprint make it a highly practical retrofit or upgrade option - enabling modern standby instrumentation even in older or space-constrained cockpits, without complicated airframe modifications.

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