Judgment;Summary — ECLI:EU:C:2024:498
Date: 2024-06-13
Language of the case: Polish
Court formation: Eighth Chamber
Subject matter: Transport
Procedure: Reference for a preliminary ruling
Origin: Poland

Summary of the request for a preliminary ruling pursuant to Article 98(1) of 
the Rules of Procedure of the Court of Justice 
Date lodged: 
3 July 2023 
Referring court: 
Sąd Okręgowy w Warszawie (Poland) 
Date of the decision to refer: 
26 May 2023 
Applicant: 
D. SA 
Defendant: 
P. SA 
  
Subject matter of the main proceedings 
Claim for compensation of EUR 600 for a flight delay of over three hours 
pursuant to Article 7 of Regulation No 261/2004 
Subject matter and legal basis of the request 
Interpretation of the terms ‘extraordinary circumstances’ and ‘unexpected [flight 
safety] shortcomings’ in the context of a flight which has been delayed due to the 
discovery of a design defect in the aircraft engine, about the possible occurrence 
of which the carrier had been warned – The range of preventive measures that a 
carrier should take within the scope of ‘all reasonable measures’, which would 
exempt it from the obligation to pay compensation for a delay to the flight – 
Article 267 of the Treaty on the Functioning of the European Union 
EN 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING – CASE C-411/23 
 
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Questions referred 
(1) Does an engine design defect revealed by the manufacturer constitute an 
‘extraordinary circumstance’ and does it come within the scope of ‘unexpected 
[flight safety] shortcomings’ within the meaning of recitals 14 and 15 of 
Regulation (EC) No 261/2004 of the European Parliament and of the Council of 
11 February 2004 establishing common rules on compensation and assistance to 
passengers in the event of denied boarding and of cancellation or long delay of 
flights, and repealing Regulation (EEC) No 295/91, if the carrier knew about the 
potential design defect several months before the flight? 
(2) If the defect in the design of the engine referred to in [Question] 1 
constitutes an ‘extraordinary circumstance’ within the meaning of recitals 14 and 
15 of Regulation (EC) No 261/2004 of the European Parliament and of the 
Council of 11 February 2004 establishing common rules on compensation and 
assistance to passengers in the event of denied boarding and of cancellation or 
long delay of flights, and repealing Regulation (EEC) No 295/91, do ‘all 
reasonable measures’ as mentioned in recital 14 and in Article 5(3) of Regulation 
No 261/2004 refer to the expectation that the air carrier should take into account 
the likely revelation of a design defect in the aircraft engine and take preventive 
steps in order to have back-up aircraft at the ready for the purpose of Article 5(3) 
of Regulation No 261/2004 in order to relieve it of the obligation to pay the 
compensation provided for in Article 5(1)(c) and Article 7(1) of that regulation? 
Provisions of EU law cited 
Regulation (EC) No 261/2004 of the European Parliament and of the Council of 
11 February 2004 establishing common rules on compensation and assistance to 
passengers in the event of denied boarding and of cancellation or long delay of 
flights, and repealing Regulation (EEC) No 295/91 – recitals 14 and 15 and 
Article 5(1) and (3) and Article 7 
EU case-law cited 
The referring court cites the following judgments of the Court of Justice: 
– Judgment of 22 December 2008, Wallentin-Hermann (C-549/07, 
EU:C:2008:771, paragraphs 21, 23, 24, 25 and 26); 
– Judgment of 19 November 2009, Sturgeon and Others (C-402/07 and 
C-432/07, EU:C:2009:716, paragraphs 61 and 69); 
– Judgment of 12 May 2011, Eglītis and Ratnieks (C-294/10, EU:C:2011:303, 
paragraphs 25 and 30); 
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– Judgment of 31 January 2013, McDonagh (C-12/11, EU:C:2013:43, 
paragraphs 29 and 38); 
– Judgment of 17 September 2015, van der Lans (C-257/14, EU:C:2015:618, 
paragraphs 36, 37, 38, 41 and 43); 
– Judgment of 4 May 2017, Pešková and Peška (C-315/15, EU:C:2017:342, 
paragraphs 20, 21, 22, 28 and 29); 
– Judgment of 4 April 2019, Germanwings (C-501/17, EU:C:2019:288); 
– Judgment of 12 March 2020, Finnair (C-832/18, EU:C:2020:204, point 2 of the 
operative part of the judgment); 
– Judgment of 23 March 2021, Airhelp (C-28/20, EU:C:2021:226, paragraph 22). 
The referring court also cites the Opinion of Advocate General L. Medina in 
Joined Cases TAP Portugal (Death of the co-pilot), C-156/22 to C-158/22, 
EU:C:2023:91, points 30, 46 and 58. 
Succinct presentation of the facts of the case 
1 On 2 July 2018, J.D. (the passenger) entered into a contract of carriage with 
P. S.A. (the air carrier) for the journey from Kraków to Chicago. The flight in 
question took place on the same day. It was delayed, however, a fact which caused 
the passenger to arrive at the destination airport more than three hours after the 
scheduled arrival time. On 18 July 2018, J.D. entered into an assignment 
agreement as the assignor, with P.[R] S.A. as the assignee, under which the 
passenger transferred any receivables due to him for the flight delay to the 
assignee. By application lodged on 29 March 2019, D. S.A. (formerly ‘P.[R] 
S.A.’) made an application for the payment of EUR 600 by the air carrier, plus 
statutory interest until the date of payment. 
2 In its defence, the defendant carrier submitted that the action should be dismissed. 
The carrier acknowledged that the flight in question had been delayed. It 
explained that the engines, of the mark R., which were fitted to aircraft used for 
transatlantic flights, had manifested design defects, but argued that it was 
exempted from liability for the flight delay as it had taken action to minimise 
disruptions to scheduled flights. 
3 In April 2018, the defendant carrier received information from the engine 
manufacturer R. imposing a number of restrictions on the use of the aircraft, 
which arose from design defects discovered in the engines fitted to the B. aircraft. 
The defect concerned the compressor blades. On 28 June 2018, pre-flight 
monitoring carried out on the aircraft scheduled to fly on 2 July 2018 identified 
irregularities in engine function. After engine surge had been confirmed, a visual 
inspection of the compressor was carried out and a boroscopy was performed. The 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING – CASE C-411/23 
 
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engine was declared faulty, removed and sent away for repair. Due to the lack of 
available working spare engines – which was a global problem since the 
manufacturer had not produced the required number of spare engines – it was not 
possible to replace the engine until 5 July 2018, and the aircraft was brought back 
into service on 7 July 2018. 
4 As a result of the circumstances described above, the defendant carrier decided to 
operate the flight using another, airworthy aircraft which arrived at Chicago 
airport late due to the sudden change in schedule. The flight was therefore delayed 
by more than three hours. 
5 Following the discovery of the engine design defect in April 2018, the defendant 
had on several occasions contacted other operators about leasing additional 
aircraft. 
6 By a judgment of 3 December 2021, the court of first instance dismissed the 
application, as it held that there were circumstances conferring exemption as 
referred to in Article 5(3) of Regulation No 261/2004, referring in this regard to 
the elements described in paragraphs 3 and 5 above, stressing in particular that the 
immediate cause of the flight delay in question was a manufacturing defect in the 
engine, and that the defendant had taken all reasonable measures possible to 
arrange a replacement aircraft. 
7 In this context, the court of first instance stated that manufacturing defects in an 
aircraft can be regarded neither as typical defects that should have been 
discovered earlier, nor as defects arising from the operation of the aircraft. It was 
an unforeseeable event which threatened the safety of the flight and had occurred 
suddenly during the routine operation of the aircraft. The court took the view that 
the operator had acted appropriately and professionally, had complied with the 
engine manufacturer’s recommendations and had demonstrated that the aircraft 
had been maintained in accordance with the required maintenance schedule. 
8 The court of first instance agreed that the defendant carrier was unable to resolve 
the problem that had arisen due to the fact that it was a global problem, while any 
duplication of its fleet or possession of several back-up aircraft would have 
undermined the liquidity of the company. Lack of manufacturing capacity meant 
that the engine manufacturer was unable to replace all faulty engines of all 
carriers, and the carrier did not have sufficient time to rearrange its entire network 
of connections. 
9 The applicant, D. S.A., lodged an appeal against the judgment of 3 December 
2021, claiming an incorrect establishment of the facts, and calling into question 
the assertions that the immediate cause of the delay was an extraordinary 
circumstance in the form of an engine design fault, that the defendant had taken 
all reasonable measures to prevent the delay of the flight, that the issue with the R. 
engines was a new problem in 2018 that had been previously unknown to carriers, 
and that the defendant did not have sufficient time to rearrange the entire network 
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of connections. According to D. S.A., the case did not involve extraordinary 
circumstances exempting the carrier from liability for the long flight delay. 
Succinct presentation of the reasoning in the request for a preliminary ruling 
10 The dispute concerns the interpretation of the terms ‘extraordinary circumstances’ 
and ‘unexpected [flight safety] shortcomings’ within the meaning of recitals 14 
and 15 of Regulation No 261/2004 in the context of a global design defect in an 
aircraft engine. The referring court refers to the case-law of the Court of Justice, 
citing paragraph 20 of the judgment in Case C-315/15, according to which an air 
carrier is to be released from its obligation to pay passengers compensation under 
Article 7 of the regulation if the carrier can prove that the cancellation or delay is 
caused by extraordinary circumstances which could not have been avoided even if 
all reasonable measures had been taken. 
11 Citing, inter alia, the judgment in Case C-257/14 (paragraphs 36 and 38), the 
referring court finds that certain technical problems may constitute extraordinary 
circumstances, for example, where it is revealed by the manufacturer of the 
aircraft comprising the fleet that those aircraft, although already in service, are 
affected by a hidden manufacturing defect which impinges on flight safety. 
Technical problems with aircraft can be considered to be covered by unexpected 
flight safety shortcomings, as they qualify as events that are not inherent in the 
normal exercise of the activity of the air carrier concerned and are beyond its 
actual control on account of their nature or origin. 
12 The hidden engine defect in the present case is an external event in relation to the 
air carrier. There is, however, doubt as to whether a manufacturing defect the 
occurrence of which was in some way notified, and which was therefore to some 
extent foreseeable, should also fall within the concepts of ‘extraordinary 
circumstances’ and ‘unexpected [flight safety] shortcomings’. If these 
preconditions are to be appraised, it is necessary to assess how likely it was that 
the carrier could have foreseen the occurrence and discovery of the hidden engine 
defect and the consequences of that event. 
13 The present case concerns an engine manufacturing defect which was nevertheless 
revealed by the manufacturer. The carrier was informed of the discovery of the 
engine design defect by the engine manufacturer in April 2018. However, it was 
not certain that a defect would be discovered, as cracked compressor blades were 
not discovered at each inspection. The manufacturer did not recommend the 
immediate grounding of all aircraft, and did not indicate that the aircraft were not 
airworthy. The flight in question took place on 2 July 2018, while the defect in 
this particular aircraft, which was supposed to perform the flight that day, was 
discovered on 28 June 2018. The present court therefore needs to establish 
whether the defect was beyond the carrier’s control with regard to its 
foreseeability. The only assumption that could be made was that a defect 
preventing an aircraft from being operated would be found in a certain percentage 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING – CASE C-411/23 
 
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of engines. It was not, however, possible to foresee with certainty whether the 
defect actually existed in the case in question. 
14 It should be borne in mind that air carriers must conform with strict technical and 
administrative procedures in their activities. This also applies to technical 
problems with aircraft, regardless of their cause. An air carrier is required to have 
certain procedures in place in this regard, or, failing that – for example, due to the 
specific nature of a particular event –, should take all necessary, possible and 
reasonable steps to counteract the event, which could lead to the delay or 
cancellation of the flight. 
15 These procedures were complied with in the present case. The manufacturer, 
having discovered the engine defect, recommended that all users carry out 
inspections. However, these would not necessarily lead to the discovery of the 
defect, although it was possible. The carrier carried out the required technical 
inspections and the engine defect was indisputably an event independent of it and 
beyond its control. In other words, even implementation of the procedure in 
question, and the taking of the necessary measures, would not have guaranteed 
that the carrier could control the event. 
16 It is thus necessary to interpret further the concepts of ‘extraordinary 
circumstances’ and ‘unexpected [flight safety] shortcomings’, and whether they 
would include structural engine defects which had been revealed by the 
manufacturer and which could have been foreseen, that is, to some extent 
‘expected’ or the probability of the occurrence of which was foreseeable, although 
this does not automatically imply that the carrier had the possibility of controlling 
the event. 
17 As regards the concept of ‘all reasonable measures’, the referring court points out, 
citing the judgment of the Court of Justice in Case C-315/15 (paragraph 28), that a 
carrier wishing to rely on extraordinary circumstances conferring exemption is 
required to establish that they could not have been avoided by measures 
appropriate to the situation, that is to say, by measures which, at the time when 
those extraordinary circumstances arise, meet, inter alia, conditions which are 
technically and economically viable for the air carrier concerned. 
18 The question to be addressed in the present case is what preventive measures 
taken by an air carrier should be considered reasonable. 
19 Manufacturing defects cannot be regarded as typical defects that are easy to detect 
in advance, prior to a flight. However, in view of the notice provided by the 
engine manufacturer in this case, it was possible to foresee this defect. It should be 
considered whether in this case the carrier’s obligation was to replace the engine 
(which was still in working order), or whether it should have grounded the aircraft 
until the manufacturer resolved the problem by repairing the engine or supplying a 
new one. Here it should be borne in mind that the carrier had requested a 
replacement engine for the aircraft in question as early as 5 July 2018, and that the 
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aircraft was brought back into operation on 7 July 2018, that is to say eight days 
after the engine defect had been discovered. 
20 In this regard, it is thus necessary to consider whether the carrier, having been 
aware of the situation since April 2018, should have prepared a back-up plan and 
organised replacement aircraft. Prima facie, it would appear that the carrier had 
ample time in the period between April and the beginning of July to take all 
necessary and reasonable steps to prevent a flight delay or cancellation, and that it 
could foresee that the technical engine defect might also affect its aircraft. During 
this period the carrier could have estimated how many replacement aircraft would 
be necessary to deal with the potential technical defect and decide to buy such 
aircraft or lease them from other carriers. 
21 Citing the judgment of the Court of Justice in Case C-315/15 (paragraph 29), the 
referring court points out that the carrier could not, however, be expected to make 
unreasonable sacrifices with regard to the resources of its undertaking to secure a 
spare aircraft that would be on stand-by at any time. In the present case, however, 
the defendant was aware of the possibility of the manifestation of the engine 
defect since April 2018. Since that time it had contacted eight carriers about 
leasing an aircraft. D. S.A. argues that it was possible to find 471 aircraft to 
replace the aircraft concerned in Europe alone, and that the defendant had failed to 
contact at least 18 carriers, including undertakings offering ‘wet lease’- type 
services, that is to say, aircraft together with crews and on-board services. The 
defendant carrier confirmed that since 7 September 2018 it had permanently 
leased one aircraft, and that in August 2018 it had signed two lease contracts. 
22 D. S.A. considers this action to be sluggish and aimed not at actually leasing the 
aircraft. It claims that this is in contrast to the contemporary practice of airlines, 
which is to keep spare aircraft on stand-by in case defects occur and a replacement 
needs to be sent out. For its part, the defendant carrier asserts that it would not be 
reasonable for it to be expected to have some fully crewed ‘spare’ aircraft on 
standby to carry out scheduled flights in emergencies and unexpected 
circumstances due to the enormous costs of leasing and maintaining them. 
Providing such back-up would, it argues, also undoubtedly have an effect on the 
price of the services offered.