HOME > CASES&JUDGMENTS > Judgments > Concerning flight delay due to check-in system failure, airline's default was negated

[October 2019]

Concerning flight delay due to check-in system failure, airline's default was negated

Flights were delayed due to check-in system failure. Passengers claimed damages against the airline for default. The following shows details of the case including the appeal court decision.

Presenting a view on airline's obligation of on-time air transportation, the appeal court negated the airline's default and dismissed the claim for damages on the ground that the airline had not been able to foresee the system failure.

The decision serves as a useful reference because the court showed a view on the obligation of on-time air transportation.

(Decision by the Tokyo High Court on March 25, 2010 (appeal dismissed))

Summary of the case

Plaintiffs, appellants:
X, etc. (23 consumers)
Defendants, appellees:
Y (an airline, CEO thereof)

X, etc. made a contract with Y for air travel from Haneda Airport to Kagoshima Airport (the passengers scheduled to board three different flights). In the morning on the day of departure, Y's check-in system went wrong, which stopped checking in for a while. Departure and arrival of flights to Kagoshima Airport on the day were significantly delayed.

The following shows how the system failure occurred.

Before dawn
An employee of a maintenance company entrusted by Y was changing Y's management program located in "branch A". The employee accidentally entered a wrong number in a field.
Around 4:47
Because of the input error, all the data was transmitted via "branch A", which overloaded the communication line of "branch A". As a result, the whole network of the system temporarily stopped.
Y activated the backup system and investigated the cause of network halt.
The network was recovered to the normal operation.
In order to ensure data integrity, Y transmitted check-in data registered with the backup system to the recovered host computer (i.e. data switch back). It was the first day of three consecutive holidays. Airlines on the day were nearly fully booked and a huge amount of data had to be transmitted. Then, temporary files for data of latter 4 flights out of 9 flights were directed to an error list. However, data input of the sixth flight completed slightly after the time limit of 200 seconds, and the temporary file containing the data was deleted just before being output to the error list. As a result, the host computer was terminated abnormally.1
Since data switch back did not end normally, the system became out of service under the system design.
Y restarted data switch back, as a result of which check-in operation was reactivated.
  1. 1 Usually, it takes only a few seconds to complete data switch back for the check-in system. If it's not completed within 200 seconds, data in temporary files is output to an error list. Incidentally, neither of the check-in system nor the backup system had become inoperable till then since the launch of the systems in 1989.

Although X, etc. boarded each flight and arrived at Kagoshima Airport thereafter, they had to wait for hours at Haneda Airport before departure (the first flight departed 2 and half hours later, the second flight departed 5 hours and 50 minutes later, and the last flight departed 7 hours and 20 minutes later). Some of the passengers were directed to a crowded boarding gate and had to shove through the crowd. The final flight arrived at Kagoshima Airport at 20:35, and it was too late to use public transportation there, except for a chartered bus reserved by the first flight passenger to get to the hotel, the final destination. X, etc. including the last flight passengers used the chartered bus and managed to arrive at the hotel.

X, etc. claimed damages (including damages for mental suffering) against Y for default (1. delay in performance; 2. breach of concomitant obligations).

The original court dismissed the claim, construing as follows.

1. Delay in performance

The court construed as follows: "Y has an obligation of means2, so Y is held liable for default only when Y has failed to perform on-time transportation without exercising reasonable and utmost efforts to realize on-time transportation." Y was unable to foresee that both of the check-in system and the backup system would become inoperable (it was hard to foresee that both systems would be inoperable during data switch back because no trouble had occurred before; time lag of transmission was unavoidable; even with the current technology, it was difficult to foresee the trouble caused by overlap in 0.00016 second). Therefore, the court did not recognize Y's default. Since Y's top priority was to ensure security and safety, significant flight delays were unavoidable. The court negated that Y had failed to exercise reasonable and utmost efforts to realize on-time transportation.

  1. 2 If someone has an obligation of means, the person is obligated to exercise reasonable and utmost care to bring results. If the person has exercised such care, the person will not be held liable for default. In contrast, if someone has an obligation of results, the person is obligated to bring results.

2. Concomitant obligations

The court recognized the existence of the following three obligations:

  1. Obligation to inform (in case of flight schedule change, the airline should provide passengers with confirmed information as far as possible when inquired by passengers, which is the obligation under the principle of good faith)
  2. Obligation to care passengers (if congestion is foreseeable, the airline should eliminate hazards to lives and bodies of passengers)
  3. Obligation to guide passengers (to enable them to properly board an airplane based on an air transportation contract)

However, the court did not recognize Y's breach of the three obligations due to the following reasons.

Concerning 1),
Y had to change the flight schedule several times due to disruption in timetable. Although Y had difficulty in informing passengers of the fixed schedule, it is recognized that Y informed the passengers through digital displays and PA system because X, etc. boarded airplanes and many passengers requested refund or changed flights to another airline.
Concerning 2) and 3),
lives and bodies of the passengers were not in danger.

In addition, airlines are not obligated to arrange transportation after flight arrival unless circumstances are exceptional. In the above case, the court did not recognize exceptional circumstances. It appears that Y arranged additional service for passengers who intended to visit remote islands in Kagoshima (e.g. flight on the next day, accommodation, taxi service in case of no public transportation), but X, etc. did not use the service. It is unclear whether or not X, etc. were informed about the additional service.

Then, X, etc. appealed to the higher court.


1. Delay in performance

The court considered whether or not on-time flight service was covered under the transportation contract, without determining if Y's obligation was an obligation of means or an obligation of results.

The essential service under a transportation contract is to transport people and things. Whether or not restriction on departure and arrival time is covered under a transportation contract depends on interpretation of each contract. When interpreting the above transportation contract rationally, the scheduled departure and arrival time should be observed unless on-time flight is not physically possible or there's a compelling priority (safety matter) over keeping to a schedule. As long as there isn't any higher priority than observing a schedule, Y is obligated to keep to a schedule. If there's any higher priority, it is reasonable to construe that Y is obligated to make utmost efforts to minimize delays. When a higher priority arises, safety should be prioritized over keeping to a schedule, and Y is obligated to make utmost efforts to minimize delays. If such a higher priority has been attributable to Y and the schedule has been delayed, Y is held liable for default. In the same way as the original court, the appeal court recognized that Y was not held liable for default because Y had fulfilled its obligations under the transportation contract on the ground that Y had made utmost efforts to minimize delays after the system failure, referring to the original decision not recognizing Y's negligence in the system failure.

2. Breach of concomitant obligations

The appeal court judged the claim as follows and negated Y's default, referring to the original decision.

Y was required to provide passengers with utmost appropriate information in the confused situation and to guide passengers properly while minimizing the confusion. When looking back such a case objectively, it may not be necessarily said that Y's actual communication and guidance were optimal. At the same time, correctness and swiftness are conflicting goals, and it's difficult to judge unambiguously when and to what extent information should be provided. Too much focus on swiftness may cause incorrect information to be provided, which adds to the confusion. In case of significant delay, it's also difficult to balance between minimizing confusion and expediting boarding. Y had to make a timely decision in a fluid situation. If it is recognized that Y made utmost efforts in the confused circumstances, it is reasonable that Y shall not be held liable for compensation even if Y's conduct seems insufficient from an ex-post and objective viewpoint. It cannot be said that Y's communication was problematic. Therefore, Y shall not be held liable for compensation for physical and mental suffering incurred by long hours of waiting unless there were hazards to lives and bodies of passengers. The passengers who boarded the last flight managed to ride on a chartered bus booked by the first flight passenger to get to the hotel, the final destination. The appeal court judged that Y had not been obligated to provide transportation service after arriving Kagoshima Airport, in the same way as the original court.


The first issue to be considered in this case was interpretation of the system failure. The flight delays were caused by failure of the system run by Y, not by external factors such as bad weather. If "the higher priority" was attributable to Y, Y could be held liable for default. Although the higher priority was triggered by the input error, Y had a backup system to cope with such trouble. Data exchanges between the backup system and the main system were overlapped in 0.00016 second, which stopped both of the systems and led to chaos. It may be said that it was inevitable to judge that Y had been unable to foresee the incident.

One of the key points in the appeal court was that the judge sought to interpret the obligation of on-time flight service under the air transportation contract, without determining if Y's obligation was an obligation of means or an obligation of results. The judge stated as follows, referring to automobile transportation: "Even if the arrival time is scheduled, both contracting parties recognize that on-time arrival may not be possible due to force majeure such as traffic conditions, weather, accident, etc. It does not mean that on time transportation is not the obligation of a transportation provider, nor it does not mean that the obligation is to make reasonable and utmost efforts aiming to realize on-time transportation. In principle, on-time transportation is the obligation of a transportation provider. However, transportation may be delayed or impossible due to various reasons. In case of unavoidable delay or non-performance which is not attributable to the transportation provider, the provider shall not be held liable for default. The same applies to interpretation of an air transportation contract."

Concerning the air transportation contract, the appeal court made the above decision based on the following facts:

  1. The air transportation contract is applied for, accepted and concluded based on a timetable showing scheduled departure and arrival time.
  2. Y's timetable and website state "We may change departure/arrival time and the type of airplane without prior consent."
  3. Y's terms and conditions state "In unavoidable circumstances, we may take necessary measures such as schedule change or flight cancel without prior notice. We will not be liable for any damage resulting from such measures with few exceptions."
  4. When transporting passengers by air, safety should be prioritized over anything else. Air transportation is susceptible to natural factors such as weather as well as technical and human factors such as conditions of airplanes, control system, operation of other airplanes. If these factors are disrespected, it is highly likely that safety is diminished. Safety first is the most beneficial for both passengers and airlines.

Another key point was that the appeal court mentioned four concomitant obligations in case of flight delay: 1) obligation to inform; 2) obligation to care passengers; 3) obligation to guide passengers; 4) obligation to arrange transportation service. It appears, however, that these obligations are seldom affirmed. Concerning 1) and 3), the court considered that the airline had been only required to make efforts to the extent possible under the circumstances, which might not be considered utmost efforts when looking back objectively. Concerning 2) and 3), the court considered that the airline should not be held liable for damage unless the damage had threatened lives and bodies of passengers. Concerning 4), the obligation to arrange transportation service is not imposed unless circumstances are exceptional.

Reference precedents

  1. Judgment by the Matsudo Branch of the Chiba District Court on April 17, 2009
    (original decision in LLI/DB)
  2. Judgment by the Saitama District Court on August 25, 2015
    Concerning flight cancellation due to airframe failure under an air transportation contract, the court did not recognize any compelling factor with regard to inspection and maintenance, and affirmed default by the airline (the court just affirmed a claim for damages for mental suffering, because the airfare was refunded and the financial damage was repaired).

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