07 Jul 2026

Aircraft Appraisals Explained: Why Do Base Value and Market Value Differ?

An aircraft appraisal helps lessors, investors, banks, and aviation asset managers understand what an aircraft is worth under a specific value definition. This is important because an aircraft does not have only one value. Its value can change depending on the purpose of the appraisal, the condition of the aircraft, the strength of the market, and the assumptions used by the appraiser.

Two of the most common terms in aircraft valuation are aircraft base value and aircraft market value. They are related, but they are not the same. Base value reflects a longer-term view of an aircraft’s underlying worth in a balanced market. Market value reflects what the aircraft may achieve in current trading conditions.

Understanding this difference helps stakeholders avoid misreading an aircraft appraisal. A market value below base value does not always mean the aircraft is a poor asset. A market value above base value does not always mean the aircraft’s long-term economics have improved. Each value answers a different question.
 

What Is an Aircraft Appraisal?

An aircraft appraisal is an independent opinion of an aircraft’s value prepared by a qualified appraiser. It may be used for financing, sale, purchase, leasing, insurance, accounting, investment review, or portfolio reporting.

An appraisal is not only a price estimate. It is a structured review of the aircraft, its technical status, market position, and value definition. The appraiser considers aircraft type, age, configuration, utilisation, maintenance condition, engine status, records quality, lease status, and market evidence.
 

Why Do Lessors, Investors, and Banks Need Aircraft Appraisals?

Lessors use aircraft appraisals to support lease pricing, refinancing, portfolio reporting, acquisition planning, and residual value decisions. Investors use them to assess asset risk and expected return. Banks use them to understand collateral value before providing finance.

In each case, the appraisal helps translate a technical aviation asset into a financial decision. It supports questions such as:

• Is the aircraft priced fairly?
• How much debt can the asset support?
• Is the current lease rate aligned with aircraft value?
• What residual value risk exists at the end of the lease?
• How does maintenance condition affect future cost?

These questions matter because aircraft value affects loan-to-value ratios, lease economics, impairment reviews, and exit strategy.

 

What Is Aircraft Valuation?

Aircraft valuation is the broader process of estimating the value of an aircraft. It includes the methods, assumptions, market data, technical information, and value definitions used to form a value opinion.

An aircraft appraisal is usually the formal report. Aircraft valuation is the analysis behind that report. In practice, the terms are often used together, but they are not always identical.

How Does the Aircraft Appraisal Process Work?

Before an appraiser gives a value opinion, they normally review the aircraft from both a technical and market perspective. The level of detail depends on whether the appraisal is a desktop appraisal, extended desktop appraisal, or full appraisal.

A typical aircraft appraisal process follows these steps:
 

This process shows why aircraft valuation is both technical and financial. An aircraft’s value cannot be understood properly without looking at both sides.
 

What Factors Influence Aircraft Valuation?

Aircraft valuation is influenced by aircraft-specific factors and wider market conditions. Age is important, but it is only one part of the picture. Two aircraft of the same model and year can have different values if their maintenance condition, engine status, records, or lease profile differs.

The table below explains the main factors appraisers review.
 

 

This is why aircraft valuation should not be based on age or model alone. A technically strong aircraft with complete records and good engine life may achieve a better value than a similar aircraft with near-term maintenance exposure.

 

What Is Aircraft Base Value?

Aircraft base value is an appraiser’s opinion of the aircraft’s underlying long-term value in a balanced market. A balanced market means conditions are neither unusually strong nor unusually weak.

Base value is useful because it reduces the effect of short-term market volatility. It gives lenders, investors, and lessors a more stable reference point for long-term planning.

 

Why Is Base Value Used in Aircraft Finance?

Base value is often used in aircraft finance because loans, leases, and investment structures usually extend over several years. A current market value may move quickly, but base value helps stakeholders understand the aircraft’s long-term economic position.

For banks, base value can support collateral analysis. For investors, it can support residual value assumptions. For lessors, it can help assess whether an aircraft is priced sensibly against long-term demand.

Base value is especially useful when stakeholders want to understand:

• Long-term asset strength
• Residual value exposure
• Loan-to-value assumptions
• Portfolio value trends
• Investment exit planning

However, base value should not be treated as a guaranteed sale price. It is a normalised value opinion, not a live transaction quote.

 

What Is Aircraft Market Value?

Aircraft market value is an opinion of what an aircraft may sell for in the current market between a willing buyer and a willing seller. It reflects today’s trading environment more directly than base value.

Market value is important in sale, acquisition, refinancing, repossession, lease transition, and impairment analysis. It tells stakeholders what the aircraft may achieve if exposed to the market under current conditions.

 

Why Can Market Value Move Faster Than Base Value?

Market value can move faster because it responds to current supply, demand, lease rates, financing appetite, maintenance costs, and transaction activity. If demand is strong and aircraft availability is limited, market value may rise above base value. If the market weakens, market value may fall below base value.

Base value moves more gradually because it reflects a balanced market assumption. This is why both values should be reviewed together.

 

Why Do Base Value and Market Value Differ?

Base value and market value differ because they answer different questions. Base value asks what the aircraft may be worth in a normalised market. Market value asks what the aircraft may be worth today.

Before relying on an appraisal, stakeholders should understand which value type is being used.
 

The difference between base value and market value is not a problem. It is useful information. It shows how much current market conditions are affecting the aircraft compared with its long-term value trend.
 

How Do Supply, Demand, and Lease Rates Affect Market Value?

Supply and demand have a direct effect on aircraft market value. If airlines want a specific aircraft type and few examples are available, market value may increase. If many similar aircraft are available and demand is weak, market value may decline.

Lease rates also matter. Strong lease rates can support aircraft value because they show income potential. Weak lease rates can reduce buyer appetite because the asset may produce lower returns.
 

How Does Maintenance Condition Affect Value?

Maintenance condition can create major differences between aircraft that appear similar. An aircraft with fresh checks, strong engine life, complete records, and a standard configuration may attract stronger pricing. An aircraft approaching major maintenance may be discounted because the buyer must price in future cost.

This is especially important for engines. Engine shop visits, life-limited parts, and maintenance reserves can materially affect aircraft valuation.
 

What Is an Aircraft Desktop Appraisal?

An aircraft desktop appraisal is a value opinion prepared without a full physical inspection of the aircraft. The appraiser relies on available information such as aircraft type, age, configuration, utilisation, maintenance status, records, and market data.

Desktop appraisals are common when stakeholders need a quick or cost-effective value indication. They are often used during early transaction screening, financing discussions, portfolio monitoring, and internal investment review.
 

When Is a Desktop Appraisal Useful?

A desktop appraisal is useful when a full inspection is not required or not practical. For example, a lender may request one before deciding whether to proceed with financing. An investor may use one to compare several aircraft before deeper due diligence.

A desktop appraisal works best when the aircraft information is reliable and complete.
 

What Are the Limits of a Desktop Appraisal?

A desktop appraisal has limits because it depends on the quality of the information provided. If maintenance data, engine status, utilisation, or records are incomplete, the value opinion may be less precise.

The table below shows when a desktop appraisal may be enough and when deeper review may be needed.
 

A desktop appraisal should not replace technical due diligence when the transaction requires detailed condition verification.
 

What Is an Aircraft Valuation Blue Book?

An aircraft valuation blue book is a reference source that provides aircraft value data by type, age, and market assumptions. It can help appraisers, lenders, investors, and aircraft owners compare general value ranges across aircraft models.

Blue book values are useful, but they should not be used alone. They may not fully reflect the condition, maintenance status, engine life, lease profile, or transaction context of a specific aircraft.
 

How Should Blue Book Values Be Used?

Blue book values should be treated as a benchmark, not a final answer. They can help stakeholders understand broad value trends, but a specific aircraft may trade above or below the reference depending on its actual condition and market timing.

A practical approach is:

1. Use blue book values to understand the general value range.
2. Review comparable market evidence.
3. Check aircraft-specific maintenance and engine status.
4. Confirm records quality and configuration.
5. Compare the final appraisal value against the transaction purpose.

This approach helps avoid over-reliance on a generic value reference.
 

What Should Investors Review Before Relying on an Aircraft Appraisal?

Investors should review the assumptions behind the aircraft appraisal before relying on the value conclusion. A value figure is useful only when the reader understands what it represents.

Important questions include:

• Which value definition was used?
• Was the aircraft physically inspected?
• What maintenance information was available?
• Were engine status and LLP life reviewed?
• Were comparable transactions considered?
• Does the appraisal reflect current market conditions?
• Are any assumptions or limitations clearly stated?

These questions help investors understand whether the appraisal is suitable for the decision being made.
 

Conclusion: Why Aircraft Appraisals Matter in Aviation Asset Management

Aircraft appraisals matter because aircraft value is not fixed or simple. The same aircraft may have a base value, market value, desktop appraisal value, and future value depending on the purpose of the report.

For lessors, banks, investors, and aviation asset managers, understanding the difference between aircraft base value and aircraft market value is essential. Base value provides a long-term reference. Market value reflects current trading conditions. Both are useful, but they answer different questions.

The strongest aircraft valuation decisions come from combining appraisal expertise with technical due diligence, market evidence, maintenance review, and clear value definitions.
 

FAQs

What is an aircraft appraisal?

An aircraft appraisal is an independent opinion of an aircraft’s value prepared by a qualified appraiser for finance, sale, leasing, investment, insurance, or portfolio reporting.
 

What is the difference between aircraft base value and aircraft market value?

Aircraft base value reflects long-term underlying value in a balanced market. Aircraft market value reflects current trading conditions and what the aircraft may achieve today.
 

What is an aircraft desktop appraisal?

An aircraft desktop appraisal is a value opinion prepared using available aircraft and market information without a full physical inspection.
 

Why do aircraft appraisals differ?

Aircraft appraisals may differ because appraisers use different value definitions, assumptions, market evidence, maintenance information, and inspection levels.
 

What is an aircraft valuation blue book?

An aircraft valuation blue book is a reference source that provides value data by aircraft type, age, and market assumptions. It is useful as a benchmark but should be reviewed with market evidence and aircraft-specific data.