Finding the cause of your delay and why it matters
Flight delays are the most common flight disruption, and they can happen for countless reasons. In some parts of the world, like the United Kingdom, Canada, and Europe, delays may qualify for compensation, but only if the airline is responsible for the cause.
This means that as a passenger, you have to try to find out what caused the delay, and if you're told it was caused by maintenance or technical problems, you might be left wondering whether or not you're owed anything.
Aircraft maintenance is routine and scheduled
Planes have to undergo regular maintenance to ensure your safety as well as operational efficiency. Maintenance is planned and follows a very specific schedule based on the number of landings, takeoffs, and flight hours.
Airlines have different categories and schedules for routine maintenance work required by aviation authorities like the Federal Aviation Administration (FAA) or the European Union Aviation Safety Agency (EASA).
- Line maintenance is performed either daily or between flights to check tyre conditions, fluid levels, and damage scans.
- A-Checks are conducted every 500–800 hours of flight time or every few months. This kind of maintenance examines lights, hydraulics, and other aircraft functions.
- B-Checks are performed approximately every 6 months and examine the plane's landing gear, navigation, electronics, cabin systems, flight controls, and more.
- C-Checks take a close look at the plane's internal systems, wiring, and structure. These are much more involved inspections and take one to two weeks to complete. C-Checks typically happen every 18 months to 2 years.
- D-Checks are major inspections where the aircraft is disassembled to examine every aspect of the plane thoroughly. They take around 2 months to complete and happen only every 6–10 years.
Disrupted flight due to maintenance?You may have a right to compensation — up to £520 (€600).Check your flight
How maintenance can lead to flight delays
Airlines go to great lengths to plan for any issues that might be found between flights. They also use aircraft sensors and software that monitor problems in real time and can even predict and address issues before they cause disruption.
Most airlines have dedicated maintenance crews at larger airports, and the time required for line checks is built into flight schedules to minimise delays. If something requires more time, or if the problem is more serious, airlines (particularly the legacy carriers) can usually swap aircraft to avoid schedule disruptions.
Staffing and supply chain shortages
Since the pandemic in 2020, staffing and supply chain shortages, especially for parts, have created ongoing problems. If there are not enough workers to fix the issue, or if replacement parts are difficult to source quickly, passengers can experience delays or cancellations as a result.
Most airlines have found ways to work around these problems by stockpiling spare parts or reusing parts from grounded aircraft, and by improving pay and conditions to retain more maintenance workers.
Can maintenance count as an extraordinary circumstance?
Because maintenance is a regularly occurring, scheduled event, it does not count as an extraordinary circumstance, even when there are supply chain limitations or staffing shortages.
Carriers are ultimately responsible for maintenance and adequate staffing. Even where genuine challenges exist, they are expected to take whatever measures necessary to manage these functions.
In 2008, the Court of Justice of the European Union ruled in Wallentin-Hermann v Alitalia that maintenance problems could not be deemed extraordinary circumstances unless they could be attributed to hidden manufacturing defects, a very high bar that airlines rarely meet.
Technical and mechanical issues
While maintenance is scheduled, technical and mechanical issues happen unexpectedly and can range from engine faults to software malfunctions.
Technical issues involve the aircraft's systems, electronics, or software, including:
- Navigation and communication systems
- Autopilot systems
- Flight management software
- Weather, airspeed, and altitude sensors
Mechanical issues happen when the physical components of the aircraft are compromised, including:
- Engine problems
- Landing gear issues
- Damage to the body of the aircraft
- De-icing system failures
Are technical and mechanical issues extraordinary circumstances?
While technical and mechanical issues happen suddenly and unexpectedly, they are not usually considered extraordinary circumstances for the purposes of compensation claims.
In 2015, the Court of Justice of the European Union found in the case of Van der Lans v KLM that the extraordinary circumstances defence would not apply to unexpected technical problems, meaning compensation would be owed. The only exception is where a fault stems from a hidden manufacturing defect that the airline could not have detected or prevented, which is a rare and difficult threshold to meet.
Maintenance issues | Technical/mechanical problems | |
Is it predictable? | Predictable, scheduled inspections | Unforeseen and unpredicted |
Is the airline responsible? | Yes, always within the airline's control | Yes, unless it involves an extraordinary circumstance such as a hidden manufacturing defect |
Is a delay eligible for compensation? | Yes | Yes, unless the airline can demonstrate a genuine extraordinary circumstance |
What compensation are you entitled to?
If your flight arrived at its final destination 3 or more hours late due to a maintenance or technical issue, you may be entitled to a fixed sum under EU261 (for EU-departing flights) or UK261 (for UK-departing flights).
Route distance | UK261 | EU261 |
Under 1,500 km | £220 | €250 |
1,500 km – 3,500 km | £350 | €400 |
Over 3,500 km (3–4 hour delay) | £260 | €300 |
Over 3,500 km (4+ hour delay) | £520 | €600 |
These amounts apply per passenger and are unrelated to the price you paid for your ticket.
You can use AirAdvisor's flight delay compensation calculator to find out how much you may be owed.
How to determine the cause of your delay
Determining whether your delay is due to maintenance or a technical problem can be tricky. Here are a few steps you can take:
- Ask for clarification. Airlines are required to tell you why your flight was delayed. Ask gate agents or airline staff directly, and note exactly what they say.
- Request the reason in writing. It is common for airlines to describe causes in vague or misleading terms to avoid liability. Ask for the delay reason in writing, either from staff at the airport or via the airline's customer service channel.
- Check flight tracking sites. Sites such as FlightStats or Flightradar24 can sometimes give you useful additional context on what happened.
As long as the airline could have prevented or avoided the delay, you may be owed compensation for your trouble.
Still unsure? It costs nothing to check. Submitting a claim takes minutes, and AirAdvisor handles everything from that point on a no win, no fee basis. If you receive nothing, you pay nothing.Check your eligibility
What to do if your flight was delayed by a technical problem
The rule is simpler than most passengers realise: if the airline caused the delay through a maintenance failure, a technical fault, or a mechanical problem, and your flight arrived 3 or more hours late, you are very likely entitled to compensation. The burden of proof lies with the airline, not with you.
Over 800,000 passengers have used AirAdvisor to recover money from airlines since 2017. Most had no idea they were owed anything.
If an airline has already rejected your claim, that is not the end of the process. Read our guide on what to do when airlines deny your compensation claim to understand your options.
Tools to Help You Out
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Resources & Additional Reading
Some extra resources to help you better understand flight delay compensation:
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