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Part# 13-02569
MFR Model# 553-101-001


The AERO 553 Multi-Function Carbon Monoxide (CO) detector is a panel mounted TSO Certified unit designed especially for use in both FAA certified aircraft and experimental aircraft. Designed to fit in, and replace a standard 2.25 (2 1/4) standard instrument panel clock, the AERO 553 gives you a full set of clock, timer, temperature, cabin and density altitude functions along with highly accurate and extremely fast CO detection and PPM readings within the cockpit on an easy-to-read LCD display.

Features Include:
  • Carbon Monoxide Detection: The AERO 553 will detect and display true CO levels from 30ppm to 999ppm for real-time tracking of Carbon Monoxide in the cockpit. The 553 will alarm if the CO level exceeds 50-70 ppm for more than 5 minutes or will provide an instant alarm if CO spikes above 300ppm within one minute.
  • Clock Function: Displays Local Time and Zulu Time in a 24 hour format.
  • Flight Timer: Flight Timer starts automatically on take off when 150 ft above runway level. It can also be started manually.
  • Stop Watch: Stop watch function allows you to time any segment of your flight.
  • Inside / Outside Air Temp: Keeps track of inside and outside air temperature in both Fahrenheit and Celsius. (Requires AERO 553-500 OAT Probe)
  • Battery Voltage: Receive an instant alert when battery voltage drops / rises above pre-set levels for 14 / 28 V systems.
  • Cabin Altitude: Monitors cabin altitude and sounds an alert when you climb above 10,000 ft , 12,500 ft, and above 14,000 ft. This alert provides the pilot a reminder to equip supplemental oxygen as required.
  • Density Altitude: The density altitude is indicated based on the absolute pressure and OAT. (Requires AERO 553-500 OAT Probe)
  • RS-232 Output: Indications/Alerts may be configured to display on select 3rd party avionics products (contact Guardian Avionics for updated list)
  • Remote Annunciator Light: A Remote Annunciator Light may be installed and connected for CO alert and Altitude alert in a visible position when the AERO 553 is mounted out of plain sight.

  • All Guardian Avionics CO Detectors feature a One (1) Year Limited Warranty


  • TSO Certified and designed for certified single and multi-engine piston engine aircraft.
  • Dimensions: 2.25 in. W x 2.25 in. H x 2.5 in. D.
  • Weight 7.5 oz.
  • Input Power Input power 9-30 VDC - Power usage less than 2 watts.
  • Circuit breaker 2 amps.
  • RS-232 Serial Connection included for reporting on external systems (see list).
  • Internal fan for optimum sensing.
  • Shielded to prevent EMI (Electro-Magnetic Interference) with aircraft systems.
  • Audible alarm with varying pitch at 85 dB.
  • LED Red and Amber CO Alert lights. LED Green nominal indication light
  • Temperature range 0 F to 110 F.
  • Humidity 5% to 95% (non-condensating)
  • Built-in Temperature compensating circuit.
  • CO sensor tested up to 25,000 feet.
  • 15-pin connector with RS-232 output available.



Q: Does it also act as clock w/ timing functions?

Per the manufacturer: Yes the CO guardian has a clock.

Q: How does one test and calibrate the CO detector? Can a bump test be performed? Is there instructions for test & calibration?

The unit comes calibrated from the manufacturer and can only be calibrated by the manufacturer. The installation/operators manual is included with this unit which outlines testing although, the only user executable test to be performed is the power-on self test.

Q: Does the CO sensor wear out like the cheap $3 sticker detectors found on most planes?

The CO2 sensor wears out after 7 years from date of install.

Q: What is the TSO Number that the AERO-553 follow?

Per the manufacturer the number is TSO-C48.

Q: After 7 years can the co detector be serviced or is replacement the only option?

They can be recalibrated through Guardian directly.

Q: Is there an installation manual that can be posted on the website for reference prior to purchasing the unit?

We have added the installation diagram to the web page.