Aero Safety Systems Ah502Sd Central Warning Panel

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Part# 11-15374
MFR Model# AH502


The AH502sd combines flight, engine and aircraft configuration data to generate voice and visual alerts.

The unit is programmed to warn off against switched, analog and EFIS data inputs based on the switched state, value threshold or combinations of inputs to generate envelope alarms.

Envelope alerts could include oil pressure profiles, speed/ configuration envelopes, gear not down and oxygen alerts.

Data is gathered from directly connected switches and analog inputs as well as being able to take flight and engine data from Electronic Flight Information Systems (EFIS) and Engine Monitors when available via serial buses.

Alerts are mapped to custom voice and/or sunlight readable and auto dimming captions with integration to a remote Master Caution, Master Warning and alert acknowledgment switch.

The front mounted SD card allows for easy adjustment of programming and voice files.
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A configuration file defines the alerts by applying logic to defined states, threshold values or an envelope of flight, engine or aircraft configuration data.

A basic implementation example may include Oil Pressure, Oil Temperature, Low Fuel, Alternator, Starter, Doors and Hatches, Gear unsafe, Voltage and Alternator alerts. These basic alerts can all be generated using directly connected switched and analog inputs. A simple configuration file maps these to the illuminated captions and voice alerts and consolidates alerts into a Master Warning/ Caution switch.

More advanced alerts can be generated when flight and engine data is added through connection to an EFIS or engine monitor. By combining aircraft configuration data with flight and engine data, Envelopes and Profile alerts can be generated. Examples include recognizing that the landing gear should be down based on airspeed, rate of descent and Height AGL, that oil pressure is too low for the current RPM, that airspeed is outside of the envelope for the current aircraft configuration or that oxygen should be on above a specified altitude.

Careful thought has gone into human factors with auto mute on startup to keep the cockpit quiet when you turn on the master switch and adjustable damping on alert triggers to prevent transitory events causing unnecessary alarms. If your EFIS data feed is off or faulty, the system generates a voice alert to let you know.

The optional AH501 Master/Caution attention-getter / acknowledgment switch helps to draw the pilot’s attention to an anomaly, its switch turns unacknowledged captions to steady and mutes the audio.

Custom legends, voice alerts, and basic configuration are all included.

The unit measures 10.8in(275mm) by 0.67n(17mm) and has a panel depth of 1.35in(34mm) as detailed in the Panel Drawing and Installation sheet.

In the Box

  • AH502SD Central Warning Panel
  • Installation kit
  • Installation Manual


  • Programmable voice and visual alerts
  • Switch state, threshold value, profile and envelope alerts
  • Auto mute on start and alert damping prevent unnecessary warnings
  • Full direct-sunlight readable display with automatic dimming
  • Double-redundant high-MTBF LED arrays
  • Integration of remote Master Caution/ Master Warning
  • Press-to-Test operates all captions and audio
  • High quality design and construction
  • 2 RS232 Interfaces to EFIS, engine monitors or AH504 expansion unit
  • SD Card for ease of configuration and audio changes
  • 8 switched and 2 analog inputs
  • 2-year warranty


Is the system suitable for certificated aircraft?
  • The AH500 family instruments are designed and tested for experimental and light sport aircraft applications. We are working towards achieving approvals for certificated GA aircraft and please get in touch if you would like to support our application for STC or have an interest in certified equipment.
What custom configuration is possible for the AH502SD?
  • Each legend and voice alert is driven by logic defined in a custom configuration file. Inputs are taken from serial data interfaces with common EFIS and engine monitoring equipment as well as directly connected analogue and digital inputs and ‘mapped’ through programmable logic to legends and voice alerts.

    The logical mapping allows IF, AND, OR, GREATER and LESS commands allowing both simple alerts and more complex 'envelope' alerts to be generated.

    A simple alert could be generated using Garmin G3X fuel level data to generate a left or right low fuel visual and audio alert when fuel level falls below a specified value.

    A complex 'envelope' alarm could be RPM dependent Low Oil pressure where an allowable oil pressure profile is programmed depending on RPM.

    Both AH500 and AH502 have a number of directly fed digital and analogue inputs as well as one or two RS232 serial data interfaces that allow the unit to capture multiple variables and states to create sophisticated alert logic.

    Each legend is a separate lens that is etched to produce your custom text.

    Custom audio clips are mapped through the logic. Multiple audio files can be associated, through different logic scripts, to the same legend.

    e.g. a “CHECK DOOR” legend can be generated using a number of directly connected digital inputs to generate multiple audio files for the same legend, e.g.“Warning. Pilot Door is not closed” as well as “Warning. Co-Pilot Door is not closed” etc…

    Voice alerts can even be generated without having an associated legend, allowing for more alerts than the available legends.
What is the pricing and availability of the AH500 or AH502 with custom configurations of captions, logic and audio?
  • Charges for custom configuration are typically free of charge for simple configurations provided a completed order form is provided at time of order. Complex logic implementations will attract a fee. Please contact us through the support form with information about your requirements and we will confirm.
I already have an EFIS and Engine Monitoring System – why do I need a Central Warning system?
  • Pilots of military and commercial aircraft recognise the benefits of having a custom centralised warning system with integrated master caution. Alerts are prioritised, clearly presented, consistently voice annunciated and can be acknowledged.

    Alerts are otherwise scattered between EFIS, EMS and other indicator systems, the pilot may mis an alert or not know where to look when an audio alert is generated.

    The AH500 family of warning systems cleverly allows installers to create a custom system at prices suitable for the general aviation market. It produces intelligent alerts which combine multiple data and present the alerts in a single centralised and prioritised visual and audio interface.

    Sensors do not need to be replicated since the AH500 Central warning systems collect data from existing data sources with serial data connections available to Garmin, Grand Rapids, Electronics International, Dynon (among others) EFIS and engine monitoring systems.
How do I trigger alerts using data from my EFIS or Engine Data System?
  • The AH500 and AH502 connects over RS232 to most EFIS and Engine Monitoring systems including Garmin, Grand Rapids, Dynon and Electronics International.

    Through the XML file the data published on these systems busses can be mapped through logic to the voice and visual alerting system.

    Please contact us through the support form with information about your requirements and we’ll confirm compatibility.
Who can install the System?
  • It is recommended that an avionics installer installs the unit. We provide information within this website and provide free of charge support to assist in configuration and installation by telephone and email for installers in the USA and Europe.



Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Do I need the AH501 MASTER CAUTION / WARNING ANNUNCIATOR SWITCH to install this annunciator? It is not clear in the manual.

Yes, you will need it.

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