Case Study

Boeing 787 PECS Heat Exchanger Cleaning & DAR Repair

Boeing 787 · PECS Heat Exchanger

The Challenge

The Boeing 787 has a restoration (RST) task, MPD 21-071-00, which drives the heat exchangers (HX) off-wing for cleaning every three years. The 787’s Power Electronics Cooling System (PECS) uses these heat exchangers — along with two PECS pumps and four package motor controllers (PMCs) located in the left and right wheel wells — to keep the aircraft’s power electronics within temperature limits.

Removing the heat exchangers is not a casual task. Operators have to be mindful during removal: take off the right-hand side and the aircraft cannot be powered on. For an operator that is not covered under a comprehensive global fleet-care program, this recurring scope has to be managed directly — which means finding a repair station that can clean the HX elements properly and, critically, repair them if they leak.

The Solution

Gordon Jarratt, Chief Executive Officer at Aircraft Asset Management (AAM), pointed 787 operators to QTC for exactly this work. In his words:

“If your A/C is not under Global Fleet Care, there is a superb shop in Upland, CA, called Qualified Technologies which can clean the HX elements and they can also issue a DAR repair if they leak.”

QTC cleans the 787 PECS heat exchanger elements to restore cooling effectiveness, and — where an element is found to leak — can develop and issue a DAR repair rather than condemning the unit. For an expensive, flight-important component, that is the difference between a serviceable return and a costly replacement.

Our Process

QTC approaches each 787 PECS heat exchanger the way it approaches all heat-transfer hardware: incoming inspection and documentation, thorough cleaning of the core and element passages to clear fouling, and leak and pressure evaluation to find any breaches in the brazed structure. Where a leak is found, our engineers develop the appropriate repair and validate it before the unit is certified and released.

This capability is rooted in QTC’s founding background — our team includes former Hamilton Sundstrand and Honeywell ECS engineers who understand heat-exchanger design, fabrication, and repair development from the OEM side.

The Outcome

For 787 operators managing the MPD 21-071-00 interval outside of a fleet-care program, QTC provides a certified, cost-effective path to keep PECS heat exchangers in service: cleaned to restore performance, and repaired — not scrapped — when they leak. A public recommendation from an aircraft asset management CEO is the kind of trust signal that only comes from delivering on exactly this kind of work.

About This Component Repair

Heat exchanger cleaning and leak repair is one of QTC’s core capabilities. Learn more about our aircraft heat exchanger repair and overhaul, or read our guide to how aircraft environmental control systems work.

Frequently Asked Questions

What is the Boeing 787 MPD 21-071-00 task?

It is a restoration (RST) Maintenance Planning Document task that drives the 787's heat exchangers off-wing for cleaning on a recurring interval. Operators not covered by a comprehensive fleet-care program manage this scope through a qualified repair station.

Can QTC clean and repair Boeing 787 PECS heat exchangers?

Yes. QTC cleans the 787 PECS heat exchanger elements and, where an element leaks, can issue a DAR repair, under our FAA & EASA Part 145 approvals.

Why is heat exchanger cleaning important on the 787?

The Power Electronics Cooling System keeps the 787's electrical and electronic systems within temperature limits. Fouled heat exchangers lose effectiveness, so periodic off-wing cleaning restores cooling performance and protects downstream equipment.

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