Obsolete Aircraft Part With No Drawings? How Reverse Engineering Works
It’s a problem every operator of an aging fleet eventually hits. A generator or motor component fails, you go to source a replacement,
and the answer comes back: the OEM no longer makes it, the original manufacturer is gone, or the lead time would keep your aircraft grounded for the better part of a year. And when you ask for drawings, there aren’t any.
This is the diminishing-manufacturing-sources (DMS) problem, and it’s one of the most common reasons aircraft sit idle. The good news: a component with no available source and no drawings can still be recreated through reverse engineering. Here’s how the process actually works.
What reverse engineering means for an electrical component
Reverse engineering recreates a part’s complete manufacturing data package by measuring and analyzing an existing example — without relying on original drawings. For an aerospace electrical sub-component, that means capturing everything needed to build a new one: dimensions and tolerances, materials, the winding configuration, the insulation system, and how the piece fits and functions within the larger assembly. Done properly, the result isn’t a rough copy — it’s a fully documented component with the traceability needed to support return to service.
The process, step by step
- Evaluate the sample. It starts with a physical part — even a failed one. Experienced shops can work from worn or damaged examples by inferring original dimensions from the areas that haven’t degraded.
- Capture dimensional data. Every critical dimension is measured, often using coordinate measuring equipment, to build the geometric foundation of the new data package.
- Identify materials and construction. Materials, winding details, and the insulation system are analyzed and documented — critical for electrical components, where the right insulation class and winding determine performance.
- Build the documentation. The measurements and analysis become the prints and process documentation needed to manufacture the part repeatably — so it’s sourceable again in future, not a one-off.
- Manufacture and test. The replacement is produced, then inspected and electrically tested against the established requirements before it goes back toward service.
A chance to fix the original weakness
Reverse engineering isn’t limited to reproducing the original exactly. When the original carried a known weakness — a superseded material, or a feature that tended to fail — a capable shop can recommend improvements while recreating the part. You don’t have to rebuild a known problem; you can build a better version, validated against the same requirements.
Why decades of repair history matters
Not every manufacturer reverse engineers well. The shops that do it best are usually the ones that have spent years repairing the same family of components. That repair history is the advantage: a shop that has torn down, inspected, and rebuilt thousands of these machines for decades already understands how they’re constructed, how they fail, and what “right” looks like — applying pattern recognition built over thousands of units rather than guessing from one sample. Aircraft Electric Motors HAS that experience!
The bottom line
An obsolete part with no drawings is not a dead end. Through reverse engineering, the component can be measured, documented, improved where appropriate, manufactured, and certified — keeping aircraft flying long after the original supply chain has disappeared. The key is choosing a partner that can both reverse engineer and manufacture, and that brings real repair history to the problem.
Aircraft Electric Motors reverse engineers and manufactures obsolete and sole-source aerospace generator and motor components, backed by more than 50 years of repair experience and AS9100D / NADCAP / Part 145 approvals.
Have an obsolete part you can’t source? Send it to us — drawings or no drawings.
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Frequently Asked Questions
Can you make a part if there are no original drawings?
Yes. Reverse engineering recreates the full data package by measuring and analyzing an existing sample, so drawings aren’t required.
What if the only sample I have is worn or failed?
Experienced shops can work from worn or damaged parts by inferring original dimensions from the areas that haven’t degraded.
Can the reverse-engineered part be improved over the original?
Yes. Where the original had a known weakness, materials or design features can be improved while still meeting the established requirements.
Will the replacement be certified for return to service?
A part manufactured under AS9100D / NADCAP with Part 145 backing comes with the documentation and testing needed to support return to service.
