THERMOCOAX Aeronautic Products : Carbon Brake Temperature Monitoring & Aircraft Brake Monitoring System

Thermocoax Pedigree :

THERMOCOAX has been a worldwide key player for 20 years in designing, developing and manufacturing with thermocouple sensors for the aeronautical market.
Based on the 60 years Mineral Insulated Cable produced in-house, we are providing our customers with solutions for:
– Ground applications:
 R&D programs with institutes
 Ground aero test equipment

– Flying models:
 Thermocouples and RTDs for air cabin management system.
 Thermocouples for helicopter engines with 15 000 units installed
 Alternator Bearing temperature measurement on twin aisle and double deck platforms

– Scientific tasks:
 Skin temperature on supersonic frame
 Engine Space launcher



Technical Applications of the Brake Temperature Sensor :

New technologies are rapidly developing and the brake industry is working hard to make aircraft operations safer and offer passengers more comfortable travelling conditions.

A new generation of brakes has been installed on modern aircraft. Carbon brakes developed by key brake manufacturers is the result of a long and costly program of investment in research and development.

The new carbon disk generation provides more power braking during landing but also during braking in an emergency.

Firstly, the brake thermocouple gives the brake temperature in real time and can be transformed in a “hot brake” alert to the pilot when the value goes over a predetermined temperature threshold.

It gives valuable information to the cockpit on the temperature of the right and left brakes. If these differ too much, an asymmetric friction on the brakes can cause difficulties when maintaining heading and keeping speed under control.

Thanks to this system, the pilot receives a “Go/No Go” clear message for takeoff authorization. The brake thermocouple indicates that in case of a braking emergency event during takeoff, the brake will have his full capacity to stop the aircraft on time for the safety of all passengers.

Secondly, during takeoff in hot climates, this temperature monitoring avoids a too early landing gear retraction. This avoids a risk of tyre explosion in the wheel compartment.

The brake thermocouple is now a key piece of equipment that airlines use to reduce turnaround times (TAT) in short-haul operations to around 30 minutes.


This new generation of carbon brakes replaces the old metallic brake.

Each brake manufacturer develops their own carbon technology. Specialists agreed to give carbon technology products a longer life, more braking cycles and much higher efficiency of braking especially for heavy airliners.

But carbon brake technology produces high amounts of heat energy during braking and the temperature can get very hot if the dissipation of kinetic energy is not optimum. This temperature rises to nearly 1000°C during normal braking. In case of emergency braking at full power during takeoff at full weight, the friction off the carbon disks is so powerful that the energy produced causes the temperature to rise to 2000°C.

Temperature monitoring is implemented on every aircraft platform, commercial and military. One thermocouple per brake/wheel is the rule. A typical single-aisle aircraft is equipped with 4 thermocouples, a twin-aisle aircraft 8 to 12 thermocouples, double-deck aircraft 16 thermocouples and military fighter 2.

This is an opportunity for THERMOCOAX to contribute to this program and improve the safety of the airframe and passengers every day around the world.


Technical description of brake thermocouple

When measured at nominal temperature, the thermocouple typically has the following properties:

  • K type thermocouple
  • Single-circuit, 2 wires


  • Class 1 in accordance with IEC and ASME
  • Ceramic insulator
  • Dielectric under 500V
  • Insulation resistance:
    • 1011Ω.m at room °T
    • 107 Ω.m at 600°C
  • Inconel 600 sheath
  • Ø 2.5 to 4.75mm
  • Hermetic connector EN2997
  • Hermetic connector D38999
  • 2 compensated pins


  • Oval base or mesh for easy removal from the torque tube when replacing


  • Mass: <100g
  • Environmental and safety of flight tests
  • Impact: RTCA/DO160 Sect 7 cat B, D
    • Cat B
    • Cat D
  • Vibration: RTCA/DO160 Sect 8
    • Cat R curve W
    • Cat T curve E
    • 2000 hz, 200G


  • HALT Tests


Acceptance Test Criteria of the Brake Thermocouple :

  • Temperature calibration
  • Helium leak test
  • XRay by sampling
  • Time constant
  • Visual and mechanical inspection
  • Overvoltage
  • Line resistance
  • Polarity
  • Insulation resistance
  • Dielectric 500Vac, 60Hz/60s
  • Mass
  • Final manufacturing report


Packaging and Cleanliness :

THERMOCOAX focuses on high quality Brake thermocouple products for the best stability and repeatability while in operation.

We understand our customers’ challenges to manufacturing braking systems and to make the aeronautical industry reliable and the millions of passengers safer.

At THERMOCOAX, we are working hard to contribute to these incredibly challenging programs.

THERMOCOAX has supplied many commercial programs and military platforms.

THERMOCOAX designs, develops, qualifies and produces in accordance with aircraft specifications such as :

  • Airbus 350
  • Embraer EJet
  • Mitsubishi Regional Jet
  • Irkut MC21
  • Sukhoi Super Jet100
  • COMAC C919


THERMOCOAX is the major player for brake thermocouples and is a proud contributor to great aeronautic programs.