Measure maintenance providers by work actually performed — 13,106 heavy visits over 18 months — and a league table emerges that most passengers, and plenty of industry people, would not predict. Six of the top ten are in Asia.
MRO — maintenance, repair and overhaul — is the industry's least glamorous multi-billion-dollar business. Every airliner disappears into a hangar for days or weeks at fixed intervals, and someone has to have the certified hangar, the tooling and the licensed workforce ready. Rankings in this sector are usually self-reported capability brochures. This chart takes a harder measure: the number of MRO events keeping an aircraft on the ground for more than three days, counted from September 2024 through February 2026 — work that verifiably happened, at independent providers only (in-house airline maintenance for a carrier's own fleet is excluded).
HAECO leads with 1,963 events — the Hong Kong group ahead of Europe's flagship independents, Lufthansa Technik (1,729) and AFI KLM E&M (1,517), with Turkish Technic (1,419) and Beijing-based Ameco (1,319) completing the top five. The list runs down through MRO Holdings (1,158), GAMECO (1,155), HNA Technic (1,035) and ST Aerospace (933) to STARCO at 878. The spread matters: the leader does 2.2× the volume of tenth place — a real hierarchy, but no monopoly.
Count the flags: six of the ten operate from Asia, three from Europe, one from the Americas. Heavy maintenance follows labour economics, engineering depth and — increasingly — where the fleets themselves are growing, and the delivery map shows exactly where that is. Every one of 2025's record deliveries is a future heavy-check customer: today's delivery boom is tomorrow's hangar queue.
Ten providers, one metric, big spread — a bar chart would work, and a boring rank list is what this data usually gets. The radial HUD earns its format by making the hierarchy circular and compact: each arc's sweep is the event count, the colour ramp separates the leaders from the pack, and hovering any arc gives the exact figure. Crucially, the subtitle carries the methodology — events over three days on ground, 18 months, independents only — because a ranking without its definition is just decoration.
One row per entity, plus the value that ranks them. Add a couple more columns for extra rings.
| provider | events |
|---|---|
| HAECO | 1,963 |
| ST Engineering | 1,410 |
Novice tip: just the entity and its number — the agent ranks them, draws the arcs to scale and builds the HUD read-out. No need to sort or normalise; it does both.
Strip away self-reported capability claims and count actual hangar visits, and the maintenance world looks like this: Asia-centred, HAECO-led, with Europe's two flag-carrier spin-offs still holding podium places. It's the part of aviation nobody photographs — and one of the clearest demand signals in the industry, because flying hours always, eventually, become maintenance events.
Have operational or ranking data that deserves better than a table? Drop it into the Nomogram Lab agent for three chart proposals, see the United fleet HUD for the same format on different data, or browse the portfolio.