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HMU Maintenance: Enhanced capabilities and tailored overhauls

HMU Maintenance

Enhanced capabilities and tailored overhauls

Since the beginning of the year, AFI KLM E&M has been offering its customers more targeted HMU maintenance services, with reduced costs and timeframes thrown into the bargain.


Regulating the pressure at which fuel is pumped through the tank and injected into the engines, the HMU (hydro-mechanical unit) requires maintenance for one of two specific reasons: either in the event of a breakdown, or when it has reached the accepted limit of flight hours and engine cycles. Until recently, HMU repairs were performed over two stages: mechanical overhaul, followed by a testing phase using a machine to replicate flight conditions in order to verify the HMU was fully functional. However, AFI KLM E&M’s integration of a new testing machine has boosted the MRO’s capabilities, while simultaneously enabling it to offer its customers maintenance operations which are better adapted to their needs.

Performing diagnostics to offer tailored maintenance services

“Thanks to our enhanced testing methods, we can test the HMUs before we even start tackling the mechanical side of things. This enables us to perform diagnostics to find the cause of the issue, in order to offer the customer repair services that are targeted to the exact source of the breakdown.”

Mario Fernandes Abade

Head of Development for Products and Processes.

As a result, the HMU is repaired faster and at a more competitive maintenance cost. This new machine is a real plus for our customers, who benefit from adaptive maintenance solutions, as well as for the maintenance teams who have seen their operational capacity boosted by a third.

Reinforcing our historical expertise in HMU maintenance

Air Canada, Air China, Philippines Airlines, and more: for several decades now, a wide array of airlines have entrusted the maintenance of their HMUs to AFI KLM E&M. In all, there are six engine types that can benefit from this service: CFM56-7B, CF6-80C2 and CF6-80E in the Amsterdam workshops, and GE90-94, G90-115 and CFM 56-5B engines in Paris. These facilities carry all the certifications required for customers’ operations: FAA, EASA, CAAC, etc. Another key asset is the stock of spare parts to which the workshops have access, so that components can be processed without undue delay.

“It’s a win-win situation. We can now work faster and more efficiently, and our customers benefit from made-to-measure solutions. This helps to avoid, for example, having to go through the full-scale overhaul of an HMU that hasn’t yet exceeded its flight-hour potential.”

Marco Gerrits

Mechanic specialising in engine components