Aerospace Sealant Substitution: The Hidden Procurement Risks

Aviation is not an industry where “close enough” is an acceptable outcome. The stakes are too high and the consequences too severe for almost-equivalent solutions. In the aerospace industry, the right product must be used to meet manufacturer guidelines, aviation authority requirements, and military performance standards. These are not semantics; the difference between operational efficiency and catastrophic failure often rides on a razor’s edge, driven by critical variations in aerospace chemicals and sealants.

Just because a product is aviation-rated does not mean it’s the right material for a specific aircraft design or maintenance procedure. Different regions of an airframe require different corrosion inhibitors, adhesives, joint compounds, or fuel-tank sealants. Using the wrong product introduces procurement risks, regulatory risks, and long-term safety hazards that can quietly undermine performance and customer satisfaction.

The High Stakes of “Almost Equivalent” Sealants

Procurement teams must resist the temptation to accept “almost equivalent” sealants, adhesives, solvents, or consumables. There is a right product for every aerospace application, and the wrong choice can compromise quality requirements, regulatory compliance, and financial health.

Greenwood Aerospace supports supply chain leaders by offering nearly 1,000 aerospace consumables on GSA Advantage, with more on the way, to help organizations ensure the seamless integration of approved materials into their maintenance operations. As global supply chains face unprecedented disruptions, maintaining a reliable source of approved aerospace chemicals is critical for sustainability, performance, and safety.

Understanding Aerospace Procurement Fundamentals

This is a two-fold problem:

  • Procurement has its own rules and must source parts, consumables, and components through approved suppliers.
  • Aircraft have specific material requirements that must match aviation authority regulations, OEM specifications, and industry standards.

The problem arises when these two worlds do not overlap. Procurement professionals sometimes become limited to what is currently listed on GSA or available from manufacturers. When the exact item is not available, organizations may feel pressure to substitute “similar” materials. That’s where risk management must trump convenience. Procurement teams are limited by compliance rules, contract vehicles, and approved sourcing channels. When the required sealant or chemical is not listed or out of stock, they may resort to substitutes that do not match technical data sheets, safety data sheets, or regulatory requirements. This mismatch creates procurement risk, operational challenges, and long-term maintenance issues.

What is Procurement in Aerospace?

Aerospace procurement is more than purchasing—it’s a structured framework that combines supply chain management, engineering validation, regulatory compliance, and continuous improvement. Every aerospace material must be vetted for compliance with FAA, EASA, or DoD regulations. These regulations exist to maintain safety, mitigate risk, and streamline operations across the industry.

Procurement specialists must understand technical data sheets, track regulatory changes, maintain compliance documentation, and ensure suppliers meet strict quality standards. These responsibilities make aerospace procurement a highly specialized discipline that requires analysis, continuous monitoring, and collaboration between engineers, manufacturers, and supply chain organizations.

What is the Problem with the Aerospace Supply Chain?

Global supply chains are facing unprecedented volatility. Raw material shortages, extended lead times, supplier disruptions, and escalating costs affect every corner of the aerospace industry. Supply chain leaders must now develop strategies that preserve working capital, maintain operational efficiency, and ensure the availability of critical materials.

This pressure often tempts organizations to substitute “almost equivalent” sealants or consumables to keep operations running. But these short-term solutions carry long-term risks that can compromise aircraft reliability, effectiveness, and safety.

Chemical Equivalency in Aerospace: The Technical Reality

True chemical equivalency in aerospace means materials are identical in molecular structure, performance characteristics, environmental survivability, and regulatory approval. Equivalency requires more than assumptions; it demands alignment with industry best practices, aviation authority certifications, and documented evidence through technical data sheets.

Sealants are engineered for particular use cases. Substituting the wrong class, viscosity, durometer, or cure profile can compromise adhesion, flexibility, or chemical resistance. A sealant that performs okay in the shop may fail under vibration, pressure, or fuel immersion. These failures create risks for operations, customers, and employees.

Industry standards require replacement materials to meet or exceed all OEM specifications without exception.

What is an Example of Chemical Equivalence?

A good example is comparing MIL-PRF-5606 to MIL-PRF-83282 hydraulic fluids. They look similar but perform differently under thermal stress. MIL-PRF-5606 has a petroleum-based formulation that is flammable, whereas MIL-PRF-83282 has a synthetic base designed to reduce fire risk.

The same holds true for common aerospace sealants:

That’s why procurement teams must track regulatory directives, analyze safety data sheets, and refer to technical data sheets before making sourcing decisions.

How to Find Chemical Equivalence

Chemical equivalence must never be assumed; it must be proven. Procurement teams and quality organizations should use a risk-based approach that includes:

1. Review Technical Data Sheets (TDS)

Compare:

  • Viscosity
  • Shore hardness
  • Cure rate
  • Temperature range
  • Chemical compatibility

These are almost always available through the manufacturer’s website or by contacting the manufacturer directly. The TDS is the master list of a product's salient characteristics. 

2. Review Safety Data Sheets (SDS)

Verify:

  • Hazard classifications
  • Shelf life
  • Storage requirements
  • Transportation regulations

The SDS is always available from the manufacturer; you can contact them or check their website, which is usually online. A simple Google search like ‘PR-1440 SDS’ will usually bring it up. 

3. Engineering Review & Performance Monitoring

Engineering must validate chemical equivalency through historical data, past performance, and accelerated testing.

4. Supplier Documentation

Manufacturers should provide:

  • Certificates of Conformance
  • Shelf-life verification
  • Compliance documentation

5. Continuous Improvement + Regular Audits

Organizations should conduct regular audits to evaluate:

  • Supplier reliability
  • Internal procedures
  • Material traceability
  • Risk management controls

The Regulatory Framework: Why Standards Exist

Aerospace regulations exist to protect passengers, aircrews, maintainers, and organizations. When a material deviates from approved specifications, it’s a compliance failure even if it appears to work okay.

Aviation authorities require strong documentation, a structured framework, and ongoing analysis because:

  • Sealants degrade over time
  • Materials can fail under environmental stress
  • Variations in chemical composition become safety hazards

Regulators don’t accept “best guess” equivalency. Only documented compliance is acceptable.

What is AS9100 for Aerospace Quality?

AS9100 ensures procurement, sourcing, and quality systems follow industry best practices. It covers:

  • Supplier controls
  • Risk management
  • Corrective actions
  • Continuous monitoring
  • Performance metrics
  • Structured procurement procedures

Under AS9100, unauthorized substitution is a direct violation that requires investigation, containment, and corrective action.

What is Aviation Compliance?

Aviation compliance means aircraft materials must match:

  • FAA-approved maintenance practices
  • OEM engineering requirements
  • Military T.O. specifications
  • Environmental and chemical safety regulations

Compliance failures affect operations, cash flow, and customer satisfaction.

What does MOC (Means of Compliance) mean?

MOC is the approved method for showing compliance with regulations.

For sealants and chemicals, MOC usually includes:

  • Test data
  • Material specifications
  • Certificates of Conformance
  • Engineering validation

If a substituted material lacks an approved MOC, the aircraft is no longer compliant, regardless of short-term performance.

Quality Control: The Defense Against Substitution Risk

What are the four types of Quality Control?

  1. Incoming inspection
  2. In-process validation
  3. Final verification
  4. Continuous monitoring

These practices ensure materials meet all quality and safety requirements throughout operations.

What is Quality Control in Aviation?

Aviation QC certifies:

  • Material traceability
  • Correct sealant selection
  • Proper installation procedures
  • Compliance with regulatory requirements
  • Documentation for audits and investigations

QC protects organizations, employees, and customers by ensuring only approved materials enter the aircraft.

The Hidden Costs of Sealant Substitution

Direct Financial Impacts

The hidden costs include:

  • Rework labor
  • Additional inspections
  • Grounded aircraft
  • Lost operational efficiency
  • Increased working capital requirements

Even a small bead of improperly applied sealant can require complete resealing—a costly, intensive process.

Operational Consequences

Substituting the wrong material can cause:

  • Fuel leaks
  • Structural separation
  • Corrosion
  • Environmental degradation

These issues directly impact mission readiness and operational success.

Compliance and Liability Risks

Non-compliance exposes organizations to:

  • Regulatory findings
  • Contract penalties
  • Warranty denial
  • Loss of customer trust

These risks can impact the financial health and reputation of entire organizations. Worst-case scenario, but imagine if an incident or accident occurs and non-compliant materials are found to be the culprit? 

Accident investigations probe ALL details, and non-compliant materials and the practices leading up to an accident will be examined if they are contributing factors.

Long-Term Strategic Costs

Over time, incorrect materials lead to:

  • Reduced the lifespan of aircraft components
  • Additional inspection cycles
  • More frequent maintenance
  • Sustainability challenges
  • Higher total lifecycle costs

These long-term impacts are far greater than the cost of the correct sealant.

Building a Risk-Based Substitution Framework

A robust framework should include:

Risk Management Framework — Aerospace Procurement

Reference Guide · Aerospace Procurement

Risk Management Framework — Components & Outcomes

Six framework components for structured risk management in aerospace materials procurement

Framework Component Purpose What It Helps Organizations Do Primary Outcome
Structured Risk Management Framework Components
Risk Assessments Identify potential hazards before procurement or application Highlight vulnerabilities in materials, suppliers, and processes Prevents improper material selection and reduces substitution risk
Engineering Approval Flows Ensure technical oversight and compliance Validate chemical equivalence, material suitability, and regulatory alignment Guarantees that the correct material is approved before use
Supplier Reliability Scoring Evaluate supplier consistency, compliance, and delivery performance Prioritize high-quality suppliers, remove unreliable ones, and strengthen supply chains Improves reliability, reduces procurement delays, and confirms quality
Monitoring Tools (Automation + ML) Enable real-time tracking of material usage, performance, and anomalies Detect irregularities, forecast demand, and identify noncompliant sourcing behaviors Supports proactive risk mitigation and predictive maintenance
Performance Tracking Using Historical Data Compare current outcomes to past material and supplier performance Identify long-term trends, failure modes, and improvement opportunities Strengthens decision-making based on measurable evidence
Regular Audits & Corrective Actions Validate compliance, documentation, and process alignment Correct deviations, enforce standards, and maintain regulatory readiness Ensures continuous improvement and minimizes operational risk
Framework components should be implemented as an integrated system. Each element reinforces the others to build organizational resilience and maintain regulatory compliance across all aerospace procurement activities.

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This allows organizations to identify areas for improvement and proactively mitigate risks.

Post-Implementation Monitoring

Continuous monitoring allows for:

  • Materials perform as expected
  • Deviations are caught early
  • Operations remain compliant
  • Maintenance intervals remain accurate

Monitoring is essential for safety and reliability.

Best Practices for Procurement Professionals

Procurement professionals can reduce risks by:

Aerospace Procurement Best Practices

Reference Guide · Aerospace Procurement

Best Practices — Aerospace Procurement

Eight procurement principles for materials, compliance, and supply chain resilience

Best Practice What It Accomplishes Why It Matters in Aerospace Procurement
Materials & Technical Validation

Validate all materials against Technical Data Sheets (TDS)

 Confirms performance characteristics and material compatibility Prevents the use of "almost equivalent" chemicals or sealants that may fail under operational stresses

Review Safety Data Sheets (SDS)

 Verifies handling, storage, environmental, and hazard information Essential for safety, compliance, and maintaining regulatory documentation

Maintain material traceability

 Tracks batches, shelf life, and installation history Critical for corrective actions, investigations, and quality assurance
Supplier & Supply Chain

Use approved suppliers

 Ensures reliability, traceability, and compliance Reduces procurement risk and strengthens supply chain resilience

Develop strategies for sustainable sourcing

 Builds long-term availability and reduces vulnerability to global supply chain disruptions Supports working capital planning and maintains operational efficiency
Compliance, Audit & Risk Management

Conduct regular audits

 Identifies nonconformities, supplier issues, and procedural gaps Supports continuous improvement and regulatory compliance

Track regulatory changes

 Ensures adherence to FAA, EASA, DoD, and industry standards Prevents compliance gaps and costly rework due to outdated procedures

Implement structured risk management procedures

 Creates a framework for identifying, analyzing, and mitigating risks Strengthens organizational resilience and safeguards aircraft safety
These practices apply to all aerospace chemical and material procurement activities. Implementation should be tailored to applicable regulatory frameworks including FAA, EASA, and applicable DoD standards.

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Procurement should always favor compliance, safety, and long-term effectiveness over convenience.

Final Thoughts on The True Cost of Cutting Corners

The hidden cost of substituting almost equivalent sealants is far greater than the price of the correct material. In the aerospace industry, every sealant, solvent, adhesive, and inhibitor is critical. The wrong choice threatens operations, compliance, and safety.

Greenwood Aerospace helps organizations mitigate procurement risk by providing reliable access to essential, compliant materials that meet industry standards and regulatory requirements. With a deep catalog of aerospace chemicals, sealants, and consumables—and a commitment to quality, safety, and performance—you can maintain operational efficiency, ensure compliance, and protect the long-term health of your fleet.