28 Apr 2026
Aircraft Valuation Explained: Base Value vs. Market Value
Every major decision in aviation finance, whether a bank is structuring a secured loan, a lessor is pricing a sale-leaseback, or an investor is acquiring a portfolio, rests on one foundational question: what is this aircraft actually worth? Aircraft valuation is how that question gets answered. Yet the term means different things depending on which value type an appraiser is being asked to produce, and misreading what a valuation report actually says can result in mispriced deals, miscalculated LTV ratios, and exposure to risk that was never visible in the first place.
This guide explains the core value definitions, the factors that drive them, and how to apply them in practice.
What Is Aircraft Valuation and Why It Matters
Aircraft valuation is the process of determining the economic worth of a commercial aircraft at a given point in time, under defined assumptions about market conditions, maintenance status, and transaction context. It is performed by certified appraisers and used across a wide range of transactions, from debt financing and portfolio acquisitions to sale-leaseback structures and lease redeliveries.
The valuation determines how much capital a lender will provide, how much rent a lessor can reasonably charge, and how much risk an investor is taking on at a given purchase price. Without a reliable, independently produced value opinion, none of those decisions has a credible foundation. Aircraft appraisal services are not a formality, they are a risk management tool deployed at every stage of an asset's commercial life.
Base Value vs. Market Value in Aircraft Valuation
The most important distinction in any appraisal report is the one between base value and market value. These two figures can sit close together in a balanced market, or diverge dramatically during periods of supply shock or demand disruption. Understanding the difference between base value vs market value is essential before any valuation opinion is relied upon in a transaction.
What Is Aircraft Base Value?
Aircraft base value is a theoretical benchmark, the appraiser's opinion of what an aircraft would trade for in a stable market with a reasonable balance of supply and demand. It assumes average physical condition for an aircraft of that type and age, and a standardised maintenance status. Base value is not a prediction of today's trading price; it is a long-run anchor that smooths out cyclical noise. Lenders and lessors use it to test whether a current transaction price is sustainable across the full term of a financing structure.
What Is Aircraft Market Value?
Aircraft market value, sometimes called current market value or fair market value, is the appraiser's opinion of the most likely actual trading price under market conditions that exist right now. It assumes a willing buyer and seller, an arm's-length transaction, and adequate time for market exposure. Aircraft market value reflects supply constraints, demand pressures, and cycle position in real time. In a balanced market it tracks close to base value. When OEM delivery delays tighten supply, or an airline crisis floods the secondary market with returns, market value can diverge sharply in either direction.
Key Factors That Affect Aircraft Valuation
Once the value type is established, appraisers must account for the variables that move an individual aircraft's value away from generic published benchmarks. The two most significant are maintenance status and where the aircraft sits in its economic lifecycle.
Maintenance Status, LLPs, and Lifecycle Value
The single largest variable in any aircraft valuation is maintenance status. Appraisers normalise this using the half-life convention: aircraft half life value assumes every major maintenance event - airframe heavy check, landing gear overhaul, APU restoration, and engine performance restoration, is exactly midway through its scheduled interval. Aircraft full life value assumes all events are at zero time, fresh from overhaul. Half-life is the standard appraisal baseline; from there, the appraiser adjusts up or down to reflect the aircraft's actual condition.
Engine life limited parts require separate treatment. Aircraft engine LLP values are calculated based on cycles consumed against total cycle limits, with replacement cost prorated accordingly. LLP in aviation is one of the most frequently misread lines in an appraisal, overlooking remaining LLP life can create a value discrepancy of several million dollars on a single engine pair. Records quality compounds this further: if an operator cannot provide full back-to-birth traceability, an appraiser cannot credit the maintenance status regardless of the work performed. For a closer look at how documentation gaps affect asset value in practice, see the hidden costs of poor aircraft documentation.
Residual, Scrap, and End-of-Life Value
Aircraft depreciation rate averages 4–9% per year under normal market conditions, meaning an aircraft retains approximately 70% of its value after five years, 50% after ten, and 35% after fifteen. Aircraft residual value analysis forecasting what an asset will be worth at the end of a lease or financing term, is central to every deal model built by a lessor or debt investor.
As aircraft approach the end of their economic life, the calculus shifts from lease placement to part-out economics. Aircraft scrap value, more accurately described as part-out value, reflects what individual components, particularly serviceable engines and high-value rotables, can realise in the secondary market. For an ageing narrowbody with engines approaching restoration, part-out value frequently exceeds the value of the whole aircraft, making it the relevant floor metric rather than any appraised whole-aircraft value.
Types of Aircraft Appraisals and When to Use Them
Not all appraisals are the same exercise, and commissioning the wrong type for a transaction is a costly mistake. Aircraft appraisal services generally fall into three categories under the ISTAT framework: desktop, full, and comprehensive.
Desktop vs. Full Appraisals
An aircraft desktop appraisal is produced using market data and records review without a physical inspection of the airframe. It is faster and less expensive, appropriate for initial deal screening, portfolio monitoring, or internal valuation benchmarking. A full appraisal adds physical inspection of the aircraft and records, producing a maintenance-adjusted value that reflects actual condition rather than assumed half-life status. A comprehensive appraisal goes further, providing the records depth required to support re-registration in a new jurisdiction, typically required in repossession scenarios or cross-border portfolio transfers. For any secured lending, sale-leaseback, or deal where actual aircraft condition represents material risk, a full or comprehensive appraisal is the correct standard.
How ISTAT Appraisers Conduct Aircraft Valuation
The industry gold standard for commercial aircraft appraisals is the ISTAT Appraisers Program. An ISTAT certified appraiser must hold a minimum of five years of full-time aviation experience, at least two of which involve active appraisal work, and pass rigorous examinations covering valuation theory, technical knowledge, finance, and professional ethics. Banks and institutional investors typically require value opinions from at least one, and often two, ISTAT certified appraisers before committing capital to any significant transaction.
The methodology follows ISTAT-aligned value definitions, which codify the precise meaning of base value, market value, distressed transaction value, lease-encumbered value, and each maintenance status baseline. This standardisation ensures that value opinions produced by different appraisers are directly comparable, a requirement in any multi-party financing or portfolio transaction where each counterparty may commission their own independent appraisal.
Aircraft Valuation Trends in Today's Market
The current environment has pushed aircraft market values significantly above long-run base value assumptions across most narrowbody types. Persistent OEM delivery delays, particularly across the A320neo and 737 MAX programmes have kept airlines operating older aircraft longer, suppressing the supply of available used aircraft while demand continues to grow. This dynamic has materially slowed the aircraft depreciation rate for legacy types including the A320ceo and Boeing 737NG families, with appraisers revising five- and ten-year forecast values upward considerably compared to pre-2022 assumptions.
For investors and lessors, the risk is now on the downside: when OEM production normalises and delivery rates recover, market values may correct toward base value. Maintaining valuation discipline — anchoring deal pricing to base value rather than elevated current market value is more important now than at any point in the past decade.
How Acumen Supports Aircraft Valuation
Acumen's ISTAT-certified appraisers provide independent value opinions across commercial aircraft types, integrated into a fully connected approach to aircraft asset management across the full lifecycle from sourcing and acquisition through lease management, remarketing, and divestment. For banks, investors, and lessors who need credible, independent aircraft appraisal services as part of a transaction or ongoing portfolio review, our aviation advisory services provide the expertise to support informed decisions at every stage.
Frequently Asked Questions
What is the difference between aircraft base value and market value?
Aircraft base value is a theoretical benchmark reflecting what an aircraft would trade for in a stable, balanced market, a long-run reference that smooths cyclical variation. Market value reflects the most likely actual trading price under current conditions. Understanding the difference between base value vs market value is what separates disciplined deal-making from cycle-chasing: in normal markets the two sit close together, but in supply-constrained environments like 2024–26, market value can trade significantly above base value as OEM delivery delays restrict the supply of new aircraft.
What does half-life mean in aircraft valuation?
Half-life is an appraisal convention that assumes every major maintenance event, airframe check, engine restoration, landing gear overhaul, APU, and LLPs is exactly midway through its scheduled interval. It provides a standardised baseline used to normalise aircraft in different actual maintenance conditions, allowing direct comparison across types and vintages. It has no relation to how old an aircraft is or how long it has left in operational service.
How much does an aircraft lose in value each year?
Under normal market conditions, commercial aircraft base values decline at approximately 4–9% per year. An aircraft is typically worth around 70% of its original value after five years, 50% after ten, and 35% after fifteen. Since 2022, this rate has slowed significantly for legacy narrowbody types as OEM delivery delays have sustained secondary market demand and kept older aircraft in active service longer than historical depreciation curves anticipated.
Who can carry out an aircraft valuation?
Aircraft valuations for financing, investment, and major transactions are conducted by ISTAT-certified appraisers, the industry-recognised standard for commercial transport aircraft. Certification requires five years of aviation experience, at least two in active appraisal work, and successful completion of examinations covering valuation theory, technical knowledge, finance, and professional ethics. Banks and institutional investors typically require independent opinions from certified appraisers as a condition of capital deployment.
What is a lease-encumbered value and when is it used?
Lease-encumbered value (LEV) reflects what an aircraft is worth when it already has a live lease attached, incorporating the remaining rental income stream, lease terms, lessee credit quality, and the expected residual value at lease expiry. LEV can sit above or below outright market value depending on whether the contracted rent is above or below current market rates. It is the standard valuation type used when aircraft are sold mid-lease to investors, or when portfolios of leased aircraft are securitised in capital markets transactions.
