See how KasperAero’s NZMS-based debris detectors stack up against traditional chip detector technologies such as the two prong and disc style magnetic chip detectors.
Two Families of Traditional Detector
Traditional magnetic debris detectors used in aircraft engines and gearboxes fall into two broad categories, each collecting ferrous particles from the oil stream using a magnetic field but differing in geometry.
Prong-Style Detector
Prong-style detectors use two exposed magnetic electrodes separated by a small gap. As ferrous debris accumulates and bridges the gap, the circuit closes and triggers a cockpit indication. The footprint is small but detection depends entirely on a particle physically connecting the two prongs. The design also relies on the ferous particles landing on the chip gap.
Pole-Style Detector
Pole-style detectors use a central magnetic pole with a surrounding return path. The magnetic pole pieces draw debris towards the chip gap where the feild is strongest. Like the prong design, the output is binary. The system either trips or it does not, with no information about what caused the trip or how much debris was involved.
Fuzz Burners and Nuisance Trips
Fine conductive debris suspended in oil is a persistent source of false indications in traditional detectors. Individual particles too small to indicate a real fault can accumulate across the electrode gap and close the circuit anyway, triggering a cockpit warning that sends a crew into a precautionary shutdown for no genuine mechanical reason. These nuisance trips carry real operational and cost consequences.
To address this, some systems incorporate fuzz burners: circuits that apply a current pulse across the electrodes to burn off fine conductive buildup. Buildup which cannot be burnt off indicates a non-nuissance trip. The approach works, but fine particles represent the earliest stage of wear progression. Burning them away before they are observed eliminates data that could inform a maintenance decision, trading a nuisance trip for a blind spot in the health monitoring record.
The Resistance Measurement Approach
Engineers at Pratt and Whitney recognized the limits of simple on/off detection and developed an approach that measures resistance across the electrode gap rather than simply detecting whether the circuit is open or closed (Patent US10866201B2). As debris bridges the gap, the resistance profile provides limited additional information, differentiating between light contamination and a more significant debris deposit.
This was a meaningful step forward within the constraints of electrode-based architecture. However, the underlying approach still relies on direct electrical contact between particles and electrodes, inheriting the same fundamental vulnerabilities: sensitivity to oil chemistry, degradation of electrode surfaces over time, and no ability to distinguish particle size or count in any rigorous way.
Inherent Limitations of Traditional Designs
Despite decades of incremental refinement, traditional debris detectors share a common set of structural weaknesses that stem directly from their reliance on exposed electrodes in a fluid environment.
Nuisance Trips
Fine conductive debris bridges the electrode gap and closes the circuit without any real fault present. Fuzz burners reduce this but destroy early-stage debris data in the process, eliminating the earliest warning signs of component wear.
No Quantitative Data
A trip signal tells the crew something happened. It cannot communicate particle size, count, mass, or whether the event was a single large fragment or progressive accumulation over hundreds of hours of operation.
Cracking Epoxy and Oil Ingress
Thermal cycling causes potting compounds to crack over time, creating leak paths. Oil ingress degrades internal connections and can cause false readings or outright sensor failure in the field after extended service.
Electrodes Limit Repeatability
For a chip detector to trip, debris must physically bridge the electrode gap, a matter of chance rather than certainty. Test data confirms that the quantity of debris required to trigger an indication varies significantly from one run to the next, making consistent detection thresholds impossible to guarantee.
KasperAero NZMS Sensors
KasperAero's NZMS technology takes a fundamentally different approach to detection. Rather than relying on electrical continuity between exposed electrodes, NZMS measures magnetic disturbances directly as particles collect on the sensing face. This eliminates the failure modes inherent to traditional chip detectors while maintaining a comparable installation footprint.
NZMS sensors are designed to match the size and mounting conventions of legacy prong and pole-style detectors. They install in the same ports and environments without requiring major system redesign, making them a practical upgrade path for existing platforms and a natural choice for new designs.
What Changes Without Electrodes
Because there are no exposed electrodes, the sensing elements are fully isolated from the fluid environment. This removes several long-standing failure modes in a single design decision:
The absence of electrodes also allows the sensor to be deployed in systems where traditional detectors struggle or fail entirely, including fuel systems and environments where electrode chemistry is problematic.
Continuous Data vs. a Trip Signal
NZMS sensors produce a continuous analog output rather than a binary trip signal. This distinction matters enormously for maintenance operations. A trip signal tells you something happened. Continuous analog data tells you what happened, when it started, how it progressed, and whether the rate is accelerating.
This makes NZMS sensors natively compatible with condition-based maintenance programs, where the goal is to act on evidence of degradation rather than waiting for a fault indication. The sensor is also inherently immune to nuisance trips caused by conductive contamination or transient particle bridging. There is no gap to bridge and no continuity to interrupt.
One Current Limitation
The primary constraint on current NZMS sensors is temperature. The electronics are rated to 150°C (302°F), which covers the majority of gearbox, UAV powertrain, and small turbine applications. However, it does not reach the hottest zones found in large commercial or military turbine engines where oil temperatures can exceed this threshold.
For the large majority of platforms where KasperAero sensors are targeted, this temperature ceiling is not a constraint. And as electronics technology continues to advance, higher-temperature variants remain a clear development path for the future.