Condition Monitoring & eVTOL Rotorcraft: Some Frequently Asked Questions

November 1 2019

Recently, GPMS announced its condition monitoring pilot with eVTOL pioneer Beta Technologies. Since Health and Usage Monitoring Systems (HUMS) have historically been implemented on traditional rotorcraft, we sat down with our CEO and Chief Engineer Eric Bechhoefer to answer some questions that this project has generated.

What is Foresight MX and who is it for?

Foresight is GPMS’ predictive HUMS, which provides advanced machine monitoring on complex rotating equipment. The MX element stands for mobile as this variant was designed specifically for helicopters. The system is comprised of shipboard hardware and sensors, and cloud-based algorithms and software. Functionally, it offers Component and Engine Health Monitoring, automated RTB, and Flight Data Monitoring. We’ve targeted the light to medium helicopter segment, which frequently lacks these systems. Our value is all around enabling operators to “know about it before it matters,” giving them advanced insight into their fleet for safety, efficiency, and readiness.

Why do eVTOL rotorcraft need Health & Usage Monitoring (HUMS)?

From a maintenance standpoint, there are more similarities – like bearings, motors, rotors – to traditional rotorcraft than differences. Plus, electric motors have their own failure modes that should be monitored. So, for all the reasons that HUMS makes sense on gas turbine helicopters, it’s critical for the eVTOLs as well.

Beyond that, eVTOL OEMs will define their maintenance requirements. By factoring in systems like ours into the design, it will allow the OEMs to leverage the information that these systems provide to inform maintenance decisions in the manual and presumably drive down O&M costs more. Additionally, HUMS is part of a safety management system – which gives more control to the operator to mitigate risk.

Does HUMS become even more important in autonomous eVTOL situations?

Absolutely. We like to say that the pilot is the first HUMS sensor and without a pilot, equipment and maintenance faults may go unnoticed until it’s too late. So, the need for a system like Foresight becomes even more critical when we think about autonomous aircraft.

What HUMS system features are critical in an eVTOL environment? What do eVTOL companies need from a HUMS system?

Fundamentally, a HUMS in either a gas turbine helicopter or eVTOL will need to support: helicopter Flight Data Monitoring (exceedances/limits, etc), rotor balance, engine performance monitoring (some difference there) and condition monitoring of rotating equipment. While there is some new analysis for the electric motors, which have their own failure modes, and new mechanization to account for asynchronous rotors, the overall system is pretty much the same.

One thing we think about a lot is customer experience, because most eVTOL aircraft will be carrying passengers. Our system automatically captures regime state and builds an RTB adjustment solution that operators can easily implement. So operators can make smaller adjustments more frequently, which reduces vibration and improves the passenger experience.

The biggest difference will be in the requirements for weight saving, as eVTOL are even more sensitive to adding weight. Legacy HUMS systems, of the type on many heavy part 29 helicopters, can weigh over 100 pounds. Our system, which is a bused system, on a typical light helicopter weighs less than 10 pounds and on eVTOL can weigh even less.

Is Beta Technologies GPMS’ first eVTOL customer? If so, is GPMS actively marketing the system to other eVTOL operators?

BETA is the first eVTOL customer for GPMS. We are starting to talk to others because we think HUMS is vital to the success of this segment. As with gas turbine helicopters, these aircraft require monitoring to help ensure the health of the system. Beyond that, eVTOL OEMs will define their maintenance requirements. By factoring systems like ours into the design, it will allow the OEMs to leverage the information that these systems provide to inform maintenance decisions in the manual and drive down O&M costs more.