Engineering Changes and Drawing Errors in Aerospace
Drawing errors drive Engineering Change Orders, costing $1,000–$15,000 each. Rootstock found major projects with engineering changes exceeded budgets by 72%. Here's why it keeps happening and what actually works.
6 min read
By MLNavigator Team
Your engineer just finished a drawing. Machining starts tomorrow. Two weeks from now, QA catches a missing tolerance. Parts get scrapped. Schedule slips. Customer gets an awkward phone call.The drawing error cost you $8,500 in direct expenses. The schedule delay? Another $12,000 in expedite fees and penalties.A Rootstock study found that major projects with engineering changes exceeded their initial budget by 72%, compared to 11% for projects without changes
. Drawing errors are a significant contributor to these costly Engineering Change Orders. Not because your engineers are careless—because the system makes it easy to miss dimensional tolerances, material callouts, and revision levels.
Why This Keeps Happening
Aerospace manufacturers live and die by documentation accuracy. Engineering drawings are the single source of truth between design, manufacturing, inspection, and certification.Yet drawings remain a major source of error. The mistakes aren't exotic—they're missing tolerances, ambiguous dimensions, outdated revisions, or specs copied from the wrong part. In MRO environments, one bad drawing can pause an entire production line while engineering, quality, and the shop floor try to figure out what was actually intended.The root cause? Fragmented data across PLM, ERP, and shop-floor systems. No one catches the errors until parts are already in progress—or worse, shipped to the customer.CMMC deadlines make this more urgent. Without Level 2 certification, many MROs will be locked out of DoD contracts
. Many aerospace shops report double-digit Cost of Poor Quality as a percentage of revenue, with drawing errors as a leading contributor.An OXMaint article notes that poorly tracked Engineering Change Notices can add an average of $12 per unit in hidden warranty labor. One medical-device plant reduced mix-model scrap by 55% after automating ECO release
If you're not an engineer, here's what these terms mean:
ECO: Engineering Change Order—a formal record of changes to a technical document or design
NCR: Non-Conformance Report—formal notice that something doesn't meet requirements
FAI: First Article Inspection—regulated review of the first unit made to a new design
CMMC: Cybersecurity Maturity Model Certification—required for defense suppliers; without Level 2, no new DoD contracts
Where Errors Come From
Drawing errors slip through because QA teams are overloaded and standards get enforced inconsistently. Engineers rely on tribal knowledge or outdated checklists. The shop floor often catches errors before quality does—which means parts are already in progress.Common patterns:
Tolerances missing on critical dimensions
Material specs copied from the wrong part
Revisions released but the wrong version gets used
GD&T datums referenced but not properly defined
Surface finish callouts that don't match customer requirements
What Actually Works
MLNavigator scans drawings during design review—before they reach the shop floor. Every drawing gets checked against AS9100, ITAR, FAA requirements, and your shop's learned standards.The system runs offline on a Mac Studio or on-premises cluster. No cloud dependency. No SaaS subscription. Data never leaves your building.Each scan takes 2-5 seconds and catches:
Missing or ambiguous tolerances
Material spec inconsistencies
Incomplete GD&T callouts
Revision control gaps
Customer-specific requirement violations
Weekly, the system fine-tunes itself using LoRA adapters trained on your corrections. After a month, it knows your shop's standards. After three months, it's catching issues your senior engineers would catch—but consistently, on every drawing, every time.All scans generate audit-ready logs automatically. When an auditor asks about drawing control and traceability, you have immutable evidence of what was checked, when, and by which system version.
Legacy Flow
Engineer drafts drawing
Drawing issued
Shop finds error
ECO issued
QA investigates
Schedule slips
MLNavigator Flow
Engineer drafts drawing
Reviews with MLNavigator
System flags error
Engineer corrects
Drawing issued clean
No ECO required
That difference is everything. When errors are caught at the source, they never have a chance to multiply.
Figure 3: Comparison of legacy manufacturing workflow versus MLNavigator-optimized workflow. The legacy process shows problems discovered late in production leading to change orders and delays, while the MLNavigator process catches issues early through real-time standards scanning, preventing downstream disruption.
The Business Case
Pilot programs begin in 2026 to validate error reduction capabilities. Target measurements include reduction in drawing-related ECOs, scrap/rework costs, and approval cycle times. The goal is to demonstrate measurable ROI within a 12-week pilot period.This translates directly to:
Fewer ECOs consuming engineering capacity
Less scrap and rework on the shop floor
Faster approvals (no delays waiting for clarifications)
Audit-ready documentation by default
Reduced compliance risk for CMMC and AS9100
If you're spending $50,000 annually on drawing-induced ECOs—conservative for most shops processing 200+ drawings monthly—a 30% reduction saves $15,000 in Year 1. The system costs a fraction of that.For investors, this becomes sticky infrastructure in regulated supply chains. Shops can't easily switch once the system holds their learned standards and audit history. ROI compounds as the system gets smarter and catches more edge cases.
Try It Yourself
Schedule a demo with sample drawings. See what the system catches. If it flags errors that would have cost you money—keep using it. If it doesn't catch anything useful—you know.Either way, you're smarter than you were this morning.
MLNavigator Begins Pilot Programs in 2026
Schedule a demo with sample drawings and get instant feedback on what would trigger ECOs or audit findings. Apply now to secure your pilot slot.