[INT-05]Disputes and expert evidence
What does an aviation maintenance expert witness do?
Jet ResearchReviewed 6 min read
An aviation maintenance expert witness gives a court or tribunal an independent technical opinion on aircraft maintenance, condition and records. The expert reviews the documents and, where possible, the aircraft or parts, explains what the applicable standards required and what was actually done, and sets that out in a written report and, if called, in testimony. The opinion has to be the expert's own, and it has to hold up whichever side asked for it.
Key points
- The expert explains technical facts and standards. The tribunal decides the case.
- The opinion is only as strong as the records and evidence it rests on.
- Early involvement helps preserve evidence that is hard to recover later.
What kinds of cases need one?
Any dispute where the answer depends on how an aircraft was maintained, what condition it was in, or what its records show. The questions are technical, and judges, arbitrators and juries are not expected to know the answers unaided.
- Disputes over the condition of an aircraft at lease return or repossession.
- Claims that a maintenance organisation's work was defective or incomplete.
- Purchases where a defect or a records problem came to light after the sale.
- Damage, and how much value it took from the aircraft.
- Insurance claims that turn on maintenance history.
- Parts whose origin, approval or history cannot be established.
Jet Research's practice covers these and related areas. The full list is on the expert witness page.
What does the expert review?
The starting point is the documents: the maintenance records, the lease or contract, work orders and task cards, inspection reports, photographs, correspondence, and the regulations and manufacturer's data that applied at the time.
Where the aircraft, engine or part still exists and can be reached, the expert will want to see it. An aircraft and records inspection carried out to an agreed protocol is better evidence than a description of someone else's inspection.
What goes in the expert's report?
An expert report normally sets out:
- The questions the expert was asked.
- The expert's qualifications to answer them.
- The material reviewed.
- The standards that applied: regulations, approved data, contract terms and accepted practice.
- The facts as the evidence shows them.
- The opinions, with the reasoning that leads to each one.
- The limits of the opinion, including anything the expert could not determine.
What is the difference between a consulting and a testifying expert?
Lawyers commonly distinguish between an expert who advises the legal team in private and one who gives a disclosed opinion and may testify. The first helps counsel understand the technical side of a case. The second puts an opinion before the tribunal and is questioned on it.
Which role fits, and what follows from it under the rules of the forum, is a decision for counsel. The page for attorneys describes how Jet Research works in each.
When should counsel bring an expert in?
Early, where possible. Aircraft get repaired, parts get scrapped and records get archived. An expert involved at the start can say what should be preserved, which records to request and how an inspection should be run so that its results are usable.
An early technical view also tells counsel what the evidence is likely to support before positions are fixed. The engagement process starts with a conflict check and a case review.
What makes a technical opinion reliable?
Relevant experience, a method that can be explained, and discipline about the evidence. A reliable opinion stays inside the expert's field, rests on documents and observations that are identified, and says where the evidence runs out.
It also survives being read by the other side's expert. Part of the work is reviewing the opposing expert's report on the same terms.
What does an expert witness not do?
The expert does not decide who is liable, interpret the law or argue the client's case. Those belong to the tribunal and to counsel. An expert who starts advocating loses the thing that makes the evidence useful.
If the matter proceeds, the expert may be examined on the report at deposition or trial, or in arbitration.
Short answers.
- What qualifications does an aviation maintenance expert witness need?
- There is no single licence for the role. Courts look at whether the person has knowledge, skill, experience, training or education relevant to the question. For maintenance questions that usually means certification as a mechanic or engineer and long practical experience with the aircraft types and records involved.
- Does an expert witness work for one side?
- An expert is usually retained and paid by one party. The opinion still has to be independent. An expert gives the same answer to the same question whoever asks it.
- Can the expert inspect the aircraft?
- Often, if it still exists in the relevant condition and access can be agreed or ordered. Inspections in a dispute are normally run to a written protocol so that both sides can rely on what was observed.
- Is an expert witness only needed if a case goes to trial?
- No. Most technical disputes settle. A clear technical opinion early on often shapes how, and whether, they do.
Where this becomes a job.
INT-06Lease return disputes: the technical questions they turn onThe technical questions at the centre of aircraft lease return disputes, the evidence that answers them and what a technical expert contributes.6 min read
INT-02Back to birth traceability: what it means and why one gap mattersWhat back to birth traceability means for life limited aircraft parts, what the record has to contain, where gaps come from and what can be done about them.6 min read
INT-03Pre-purchase inspection for a commercial aircraft: scope, records and limitsWhat a pre-purchase inspection of a commercial aircraft covers, what it does not cover, how the scope should be set and what the report should contain.6 min read
General information on aircraft technical practice. It is not legal advice and it is not an opinion on any particular aircraft, lease or dispute.