Walkaround

Technology · On the aircraft

Health monitoring and predictive maintenance

ACMS data, engine trend monitoring, prognostics, digital twins

in service, uneven across fleets 2 min read · updated 15 October 2026 · checked 15 October 2026

Two independent sources on every claim.

Why it is here

It moves work from finding faults to being told about them before they happen.

At a glance

What it is

Modern aircraft report on themselves continuously. The aircraft condition monitoring system records parameters in flight, engines send trend data by datalink, and the pattern across those readings tells you how a component is degrading rather than whether it has failed.

In plain terms

Scheduled maintenance assumes a part wears out at a predictable rate and replaces it on a calendar or a cycle count. Condition monitoring watches the actual part. Prognostics goes one step further and estimates how long it has left, so the work can be planned instead of discovered.

Why it matters on the line

The practical change is not that failures get predicted. It is where the work appears in the plan.

On the line

The value is in what happens after the alert, not the alert itself. An integration that raises a flag in a portal someone has to remember to read is worth very little. An integration that generates the workcard, reserves the part and books the slot is worth a great deal, because it converts an unplanned removal into a planned one. When evaluating a system, the question to ask is what it writes into your maintenance system, not how clever the model is.

In plain terms

An unplanned removal costs far more than the same work planned, because the aircraft is already somewhere inconvenient, the part is not there, and the slot is not booked. Most of the saving in predictive maintenance is the difference between those two states, not the repair.

The engine durability stories on this site are the same subject from the other end. CFM and Rolls-Royce are both rebuilding time on wing through hardware. Health monitoring is the attempt to make the remaining removals predictable rather than to prevent them.

Adoption is uneven, and it tracks fleet age. A 787 or A350 generates far more usable data than a 737 NG, so the operators with the most to gain from prognostics are often the ones whose fleets are least able to feed it.

Where to read more

Engine durability work is covered on the CFM LEAP, Trent 1000 and Trent 7000 pages.

Sources