Remaining Useful Life Estimation for Aircraft Engines with Risk-Aware Prediction Intervals via Conformalized Quantile Regression

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Published Apr 27, 2026
Colby Robinson

Abstract

Remaining useful life (RUL) prediction is critical in
aerospace maintenance for ensuring flight safety, system
availability, and long-term sustainment. Although data
driven and machine-learning (ML) approaches have
enhanced RUL accuracy, they typically provide only point
estimates, either omitting uncertainty quantification (UQ) or
relying on fixed, fleet-wide safety margins. For safety-critical
maintenance decisions, even precise point predictions have
limited value without dependable uncertainty estimates.

To address the need for reliable RUL prediction, this paper
introduces a comprehensive framework that unifies point
estimation and uncertainty quantification while accounting
for aerospace risk preferences. The framework operates by
first using a gradient boosting regressor for its point
predictions. It then uses an asymmetric formulation of
conformalized quantile regression (CQR) to create prediction
intervals that quantify uncertainty. This asymmetric approach
deliberately allocates miscoverage unequally, which
minimizes the risk of overly optimistic predictions and aligns
the model with the operational preference for avoiding late
maintenance intervention.

The framework is evaluated on NASA's Commercial
Modular Aero-Propulsion System Simulation (C-MAPSS)
benchmark dataset. Across all four benchmark subsets, the
framework achieves test RMSE values of 13.26-16.85 with
empirical coverage of 88-92% at 90% nominal coverage.
These results confirm the framework's ability to deliver
accurate point predictions and well-calibrated uncertainty
intervals suitable for safety-critical maintenance planning.

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Keywords

Remaining Useful Life (RUL) estimation, Prognostics and Health Management (PHM), Uncertainty quantification (UQ), Conformal prediction, Conformalized Quantile Regression (CQR), NASA C-MAPSS dataset, Predictive maintenance, Aircraft engine prognostics

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