1.

MK is a pilot employed on a part-time basis (90% of full-time working hours) by Lufthansa CityLine GmbH. Due to the specific nature of the profession, his part-time employment consists in him being granted additional days of leave per year. However, there is no reduction in his number of flying duty hours during his workdays, on which he thus works as if he were a full-time pilot. In terms of remuneration of those flying duty hours, three increased rates of salary apply for the hours worked beyond three progressive thresholds of monthly flying duty hours. Those same thresholds apply uniformly to all the pilots employed by the defendant, irrespective of whether they are employed on a full-time or a part-time basis.

2.

MK took the view that the application of those thresholds results in him being treated less favourably than a comparable full-time worker within the meaning of the German legislation which transposed the Framework Agreement on part-time work (‘the Framework Agreement’). ( 2 ) Hence, he brought an action against the defendant seeking the difference between the pay that he received and the pay he claims that he should have received, were the thresholds at issue lowered proportionally in relation to his part-time employment.

3.

That action was upheld at first instance. It was, however, subsequently denied on appeal. The Bundesarbeitsgericht (Federal Labour Court, Germany), seised with MK’s appeal on a point of law, wonders whether the uniform thresholds in question indeed lead to a situation in which MK is being treated less favourably within the meaning of the Framework Agreement. In view of the Court’s case-law, and considering the doubts that have emerged on that issue in the national case-law, the referring court is uncertain about the proper test for determining whether there is an unequal treatment of a part-time employee such as MK. If the rules at issue were indeed to result in MK being treated less favourably, the referring court also seeks clarification on whether such treatment is justified by the objective pursued by those rules, namely, to compensate for a particular workload.

4.

Clause 4 of the Framework Agreement concerns the principle of non-discrimination. Its paragraphs 1 and 2 read as follows:

‘1. In respect of employment conditions, part-time workers shall not be treated in a less favourable manner than comparable full-time workers solely because they work part time unless different treatment is justified on objective grounds.

2. Where appropriate, the principle of pro rata temporis shall apply.’

5.

Paragraph 134 of the Bürgerliches Gesetzbuch (German Civil Code; ‘the BGB’) provides that any legal act which infringes a statutory prohibition is void.

6.

Paragraph 4(1) of the Gesetz über Teilzeitarbeit und befristete Arbeitsverträge (Law on part-time work and fixed-term contracts; ‘the TzBfG’) provides that ‘a part-time worker shall not be treated in a less favourable manner than a comparable full-time worker on account of working on a part-time basis, unless different treatment is justified on objective grounds. The part-time worker shall receive remuneration or another pro rata benefit, the extent of which shall at least correspond to the proportion of his or her work as compared with that of a comparable full-time worker’.

7.

MK has been employed by the defendant as a pilot and first officer since 2001. As of 2010, he has been working on a part-time basis, meaning that his working hours have been reduced to 90% of full-time working hours. Accordingly, his basic remuneration has been reduced by 10%.

8.

In practical terms, MK’s part-time employment consists in him being granted an additional 37 days of leave per year. However, there is no reduction in his number of flying duty hours during his workdays.

9.

According to the applicable collective wage agreements for the defendant’s cockpit crew, the flight duty time is one component of the working time. ( 3 ) A worker receives remuneration for additional flying duty hours (Mehrflugdienststundenvergütung), on top of his or her basic remuneration, if he or she has worked a certain number of flying duty hours in a month and has thereby exceeded (triggered) the thresholds for the higher level of remuneration. For that purpose, the collective agreements establish three different hourly rates. These are used to calculate remuneration if the worker has worked respectively 106, 121 and 136 monthly flying duty hours on short-haul flights. Lower trigger thresholds of 93, 106 and 120 flying duty hours per month apply to long-haul flights. The collective agreements make no provision, in the case of workers who work part-time, for reduction of those thresholds in line with their part-time percentage.

10.

To determine MK’s monthly remuneration for additional flying duty hours, the defendant calculates an individual trigger threshold that takes into account MK’s part-time work. For flying duty hours which MK works in excess of his individual trigger threshold, he receives the hourly pay determined on the basis of his basic remuneration. It is only when his flight duty time exceeds the trigger thresholds that he receives a higher level of remuneration.

11.

MK brought an action against the defendant, seeking payment of the difference between the remuneration already paid and the higher level of remuneration for additional flying duty hours on the basis of trigger thresholds lowered proportionally to his part-time factor.

12.

Although the Arbeitsgericht München (Labour Court, Germany) upheld that action, it was later dismissed by the Landesarbeitsgericht München (Higher Labour Court, Germany).

13.

The Bundesarbeitsgericht (Federal Labour Court), seised of an appeal on a point of law lodged by MK, observes that the thresholds triggering the higher level of remuneration for additional flying duty hours apply in a uniform manner to full-time and part-time workers. That court questions whether such circumstances result in part-time workers being treated less favourably than comparable full-time workers within the meaning of Paragraph 4(1) of the TzBfG. If there is indeed a less favourable treatment with regard to pay, that court notes that it will be necessary to examine whether it is justified by an objective ground allowing for a deviation from the principle of pro rata temporis.

14.

Observing that Paragraph 4(1) of the TzBfG transposes Clauses 4.1 and 4.2 of the Framework Agreement into national law, the referring court is unsure about the proper test for determining whether there is unequal treatment. More specifically, that court is uncertain as to whether the assessment should be based on the methodology used in the judgments in Elsner-Lakeberg ( 4 ) and in Voß ( 5 ) which involve, in its view, an examination of the various components of remuneration or whether the assessment should rather be guided by the consideration of the overall pay as decided, according to the referring court, in the judgment in Helmig. ( 6 ) The referring court indicates that the use of the latter method will lead to the conclusion that the rules at issue do not involve any difference in treatment. However, the opposite is true if the former method were to be applied. Under that approach, the provisions at issue will be upheld only if the objective pursued by them, namely to compensate for a particular workload, can be considered to be an objective ground, within the meaning of Clause 4.1 of the Framework Agreement, capable of justifying an inequality of treatment.

15.

It is in those circumstances that the Bundesarbeitsgericht (Federal Labour Court) decided to stay the proceedings and to refer the following questions to the Court of Justice for a preliminary ruling:

16.

Written observations have been submitted by MK, the defendant, the German Government and the European Commission. Those parties, together with the Danish, Polish and Norwegian Governments presented oral argument at the hearing that took place on 21 September 2022.

17.

By its first question, the referring court wonders, in essence, whether provisions such as the ones at issue, set out in collective agreements, bring about unequal treatment between part-time and full-time employees given that both categories of employees must reach the same ‘threshold’ flying duty hours to be entitled to an increased rate of salary, applicable to the hours of work beyond those threshold values. ( 7 )

18.

By its second question, the referring court wonders whether an inequality in treatment between part-time and full-time pilots arising from the uniform application of those thresholds to those two categories of workers, if established, can be justified by the objective to compensate for a particular workload.

19.

At the Court’s request, the present Opinion shall deal with only the first question.

20.

The underlying reason for that question, relating to the assessment of an existence of unequal treatment between workers, is that, in the referring court’s view, there are two different tests deriving from the Court’s case-law which may be used in that respect. The application of one test or the other might result in a different outcome, thus creating uncertainty as to the correct answer.

21.

In order to address that question, I shall first provide some preliminary observations on whether the Framework Agreement, as well as the case-law relied upon by the referring court, are applicable to the present case (A). I will then proceed with the analysis of that case-law to identify the proper test flowing from it (B). Finally, I will suggest that the application of that test leads to the conclusion that the situation at issue does not result in a difference in treatment (C).

22.

The present case concerns the interpretation of the prohibition of discrimination of part-time employees laid down in Clause 4 of the Framework Agreement. It is thus necessary to verify whether the Framework Agreement applies to MK’s situation (1) and, once that is the case, whether the case-law relied on by the referring court and discussed at length by the parties to the present proceedings applies to situations governed by that instrument (2).

23.

The rules defining the trigger thresholds at issue are contained in collective agreements. I recall that those instruments fall within the scope of the Framework Agreement, which applies, pursuant to its Clause 2.1, ‘to part-time workers who have an employment contract or employment relationship as defined by the law, collective agreement or practice in force in each Member State’. ( 8 )

24.

Moreover, as to whether the Framework Agreement applies to MK, I note that Clause 3.1 associates the term of part-time employee with ‘an employee whose normal hours of work, calculated on a weekly basis or on average over a period of employment of up to one year, are less than the normal hours of work of a comparable full-time worker’. It is true that MK does not have any fixed hours of work per week given the specific nature of his profession (to which I shall turn in more detail in part C.1 of this Opinion). That being said, Clause 4 of the Framework Agreement lays down a principle of EU social law which cannot be interpreted restrictively. ( 9 ) As regards MK’s specific situation, I understand that he works fewer working hours per year than a comparable full-time employee, as this is the necessary consequence of the additional 37 days of leave per year which he has been granted to reflect his part-time situation, as a result of which his salary has been decreased by 10%. I therefore consider that he is a part-time employee within the meaning of the Framework Agreement.

25.

Finally, there is no doubt that the salary falls within the scope of the concept of ‘employment conditions’, referred to in Clause 4.1 of the Framework Agreement. The Court confirmed that financial conditions such as those relating to pay are covered by that concept. ( 10 ) Therefore, I am of the view that MK’s claim relates to an employment condition within the meaning of Clause 4.1 of the Framework Agreement.

26.

Having established that the dispute in the main proceedings falls within the scope of the Framework Agreement, I recall that the central question in the present case is whether the situation in the main proceedings amounts to an infringement of the prohibition of discrimination of part-time employees as enshrined in its Clause 4.

27.

In emphasising its uncertainties regarding the test to be applied in the present case, the referring court relies primarily on three judgments of the Court: Helmig, Elsner-Lakeberg and Voß. It ought to be recalled that each of those cases concerns the interpretation of the principle of equal pay for men and women, laid down (at present) in Article 157 TFEU, and/or of the Equal Pay Directive. ( 11 ) Although those cases concerned also part-time employees, the Framework Agreement was not invoked. ( 12 )

28.

By contrast, and as already noted, the present case concerns the interpretation of Clause 4.1 of the Framework Agreement which is an instrument that aims specifically at promoting part-time work and eliminating discrimination between part-time and full-time employees. ( 13 ) In that respect, it establishes rules of minimal protection. ( 14 )

29.

The prohibition of discrimination against part-time employees is laid down in Clause 4.1, which provides that ‘in respect of employment conditions, part-time workers shall not be treated in a less favourable manner than comparable full-time workers solely because they work part time unless different treatment is justified on objective grounds’. Clause 4.2 adds that ‘where appropriate, the principle of pro rata temporis shall apply’.

30.

I agree with the parties to the present proceedings that made the observation at the hearing that the fact that the case-law relied on by the referring court arose from cases concerned with equal pay for men and women does not, in itself, affect its relevance for the purposes of the present case. In Helmig, Elsner-Lakeberg and Voß, the Court reasoned in two steps, as the Polish Government observed. The Court examined the alleged differences in treatment between a full-time and part-time employee before analysing whether that difference, when established, affected to a greater extent women than men (that assessment being left to the referring court).

31.

Importantly, and as recalled by the Danish Government, the prohibition of discrimination set out in Clause 4 of the Framework Agreement and the prohibition of discrimination addressed in the Equal Pay Directive are particular expressions of the same fundamental principle of EU law, namely the general principle of equality under which comparable situations may not be treated differently unless the difference is objectively justified. ( 15 ) Finally, I fail to see anything in the wording of Clause 4.1 of the Framework Agreement, or in any other provision of that instrument for that matter, that would affect the relevance of the case-law mentioned above for the purposes of the present case.

32.

As already briefly noted above, the Court made clear that the term ‘employment conditions’ used in Clause 4 of the Framework Agreement applies to the financial conditions of the employment as the opposite would deprive the principle of pro rata temporis of its useful effect, ‘that principle being intended by definition only to apply to divisible performance, such as that deriving from financial employment conditions linked, for example, to remuneration and pensions’. ( 16 ) The Court also added that the principle of non-discrimination laid down in Clause 4 of the Framework Agreement must be applied to both constituent parts of the pay and the levels of those constituent parts. ( 17 )

33.

It follows from the Court’s case-law that the principle of pro rata temporis constitutes an ‘optional tool’ to reduce proportionally certain rights of the part-time employees, in a way commensurate with the effective time worked compared to the times worked by full-time employees. ( 18 ) Indeed, taking account of the reduced working time as compared with that of a full-time worker constitutes an objective criterion allowing a proportionate reduction of the rights of the workers concerned. ( 19 )

34.

More specifically, the Court considered that it was appropriate to rely on the principle of pro rata temporis in order to reduce in proportion the duration of annual leave, ( 20 ) the amount of retirement pension ( 21 ) or the amount of child allowance. ( 22 ) The Court also accepted, in that context, an adjustment of a ceiling for the payment to be made to employees in the case of the employer’s insolvency ( 23 ) and held as compatible with the Framework Agreement rules that, for the purpose of calculating the remuneration of a full-time employee, accredit the (lesser) amount of time worked previously on a part-time basis. ( 24 )

35.

In contrast to those situations, it does not seem to follow from the case file that MK’s employment benefits or pay have been lowered compared to the benefits or pay received by the full-time pilots. Rather, I understand MK’s claim to consist in the argument that his part-time situation makes it more difficult for him to reach the uniform trigger thresholds and obtain an increased salary for flight duty hours worked beyond those thresholds. The question to be answered in that context is therefore whether the prohibition of discrimination set out in Clause 4 of the Framework Agreement covers also that specific situation.

36.

Before proceeding to the assessment of that claim, I shall clarify the test to be used in order to verify whether there is indeed a difference in treatment of part-time employees as regards pay. For that purpose, I shall now turn to the case-law relied on by the referring court.

37.

As I previously noted, the relevant case-law is, in the present context, represented by the judgments in Helmig, Elsner-Lakeberg and Voß. There is, however, no consensus among the parties to the present proceedings about the exact implications of those judgments when it comes to assessing whether there is inequality in treatment in regard to pay. In order to clarify that point, I will recount the progressive developments that occurred in those three judgments (1) and identify the test which arises therefrom (2).

38.

First, the judgment in Helmig, handed down in 1994, concerned part-time employees seeking an overtime supplement for hours worked in excess of their individual part-time working hours, even though such a supplement was granted to employees only when they exceeded the full-time working hours. The Court found that there was no difference in treatment. That was because, by getting the ordinary hourly rate for their additional time of work (above their part-time and up to the full-time working hours), the part-time employees received the same pay as the full-time employees for the same number of hours worked. It was in that context that the Court held, in paragraph 26 of the judgment, that ‘there is unequal treatment wherever the overall pay of full-time employees is higher than that of part-time employees for the same number of hours worked on the basis of an employment relationship’. ( 25 ) The resulting test thus prohibits a salary for the same number of hours worked being lower.

39.

Given the use of the term ‘overall’, the approach taken in Helmig has been referred to as the test of ‘overall pay’. Viewed in isolation, without the specific facts or context of that case, that characterisation may be, in my view, to some extent misleading because what the Court took into consideration was the ‘pay’ for the same number of hours of work. The use of the term ‘overall’ reflects, in my view, the fact that the applicants’ claim concerned their pay for their overtime work as a specific component of their salary. By contrast, that term does not mean that the Court decided not to examine the components of the salary. Rather to the contrary, the Court paid attention to those individual components (the component remunerated based on the ordinary rate and the component based on the increased salary) and decided, on the basis of that examination, that the situation at hand did not involve a differentiated treatment. ( 26 )

40.

Second, the judgment in Elsner-Lakeberg, delivered in 2004, concerned a part-time teacher. In respect of both part-time and full-time employees, the first three hours of overtime work were not remunerated as additional hours of work. Ms Elsner-Lakeberg, who was working part-time on the basis of 15 hours per week, was required to work an extra 2.5 hours. The application of the rule referred to above meant that she did not receive any additional pay in that respect.

41.

The Court held that that situation amounted to a difference in treatment. It could have reached its conclusion by applying the test established in Helmig given that, for the same hours of work, Ms Elsner-Lakeberg received less remuneration than a full-time worker (who was remunerated also for those 2.5 hours of work under the full-time schema). She was thus treated less favourably than a full-time employee. In fact, that was the reasoning adopted by Advocate General Jacobs. ( 27 )

42.

However, the Court approached the situation from a different standpoint. It explained that ‘genuine transparency permitting an effective review is assured only if [the principle of equal pay] applies to each aspect of remuneration granted …, excluding any general overall assessment of all the consideration paid to workers’. ( 28 )

43.

Applying that test to the facts of the case, the Court observed that the rule at issue represented ‘a greater burden’ for the part-time employees. ( 29 ) The fact that the number of additional teaching hours entitling an overtime supplement was not reduced for part-time teachers in a manner proportionate to their working hours meant that they were treated differently from full-time teachers. ( 30 )

44.

It follows from the Court’s reasoning that the Court decided not to use the test developed in Helmig which would have led, on the one hand, to the same general outcome as regards the existence of a difference in treatment, but which would, on the other hand, bring a rather different specific result for the applicant. Indeed had the Court applied the Helmig test, Ms Elsner-Lakeberg would have been entitled to the same pay as of the first hour worked overtime instead of the amount of time to be worked without additional pay to be merely proportionally lowered.

45.

The Court, however, decided to use – once again – the Helmig test in its judgment in Voß, which constitutes the third judicial pronouncement relevant to the present case. Voß concerned a teacher employed on a part-time basis, who worked several hours beyond her part-time contract. Those extra hours were paid at a rate lower than the rate applicable to ordinary working hours. That lower rate applied also to additional time worked by the full-time employees once they worked above their full-time limit.

46.

Referring to the test used in Helmig, ( 31 ) the Court observed that Ms Voß received remuneration which, for an equal number of hours worked, was lower than that paid to a full-time teacher, in respect of the hours of work worked beyond her part-time and up to the ordinary full-time. ( 32 ) The Court then went on to explain why such a situation arose and did so with ‘an examination of the components of the remuneration’, which, in casu, were the respective number of part-time and full-time working hours, as well as the fact that the lower rate of remuneration applied for part-time teachers as of the first hour exceeding their normal (part-time) working time, whereas it applied to full-time teachers only as regards hours worked beyond the full-time level. ( 33 )

47.

I note that much of the discussion between the parties to the present proceedings has revolved around the proper test to be derived from Voß. As follows from the description above, the Court decided to use the test developed in Helmig. It referred to that test and applied it.

48.

The Commission argues to the contrary, pointing in that respect to the use of the phrase ‘by contrast’ in paragraph 32 of Voß. In that paragraph, I note that the Court describes its case-law and draws attention to the respective differences in outcome in Helmig, on the one hand, and in Elsner-Lakeberg, on the other: there was no difference in treatment in the first one and, ‘by contrast’, there was a difference in treatment in the other. ( 34 )

49.

The Commission’s argument is thus rather perplexing. As the Danish and Norwegian Governments cogently explained at the hearing, the term ‘by contrast’ is simply part of the description that the Court makes of its own previous case-law and does not reveal anything about the Court’s choice in Voß between the two approaches offered respectively by Helmig and Elsner-Lakeberg.

50.

What is genuinely revealing about that choice is, as I already noted, the fact that the Court referred in Voß to the test developed in Helmig and applied it to the facts of the case. ( 35 )

51.

In fact, the Court went even further and impliedly distanced itself from the method used previously in Elsner-Lakeberg since, when it describes (in Voß) its own reasoning, as previously given in Elsner-Lakeberg, that description is not entirely accurate. Instead of describing the ‘greater burden’ method which the Court actually used in Elsner-Lakeberg, the Court explains, a posteriori, the result arrived at in that case by a rationale taken from Helmig which, however, is entirely absent from the reasoning in Elsner-Lakeberg. ( 36 )

52.

That being said, it is true that in paragraph 36 of Voß, after having already concluded that there was a difference in treatment (by application of the test developed in Helmig), the Court turns to ‘an examination of the components of the remuneration’ at issue. However, the reference to ‘components of the remuneration’ does not shift the analysis to the examination of the proportional impact of the ‘burden’ that the remuneration based on a lower salary rate would represent for the part-time employee. Rather the reference to the components of the salary simply aims at explaining in greater detail the previous conclusion as to the lower pay that Ms Voß received for the hours that she worked beyond her individual part-time work. ( 37 )

53.

That important reference alludes, in my view, to the idea that, as was previously considered by Advocate General Jacobs in JämO, ‘treating each element of remuneration independently for the purpose of an equal pay comparison will in general be the only proper way to ensure equality … to achieve transparency and ensure effective judicial review’. ( 38 )

54.

Indeed, when the comparison of the respective components is possible, the Court engaged in a more detailed analysis and refused to accept that some components of a salary could mutually compensate each other. In that vein, it refused, in Barber, to offset discriminatory pension rights against a higher amount of the redundancy payment because the resulting situation was still less advantageous for the discriminated group. ( 39 ) That said, there may indeed be circumstances in which such an examination will not be feasible because of the complexity of the pay scheme. The only method that will make a comparison meaningful under such circumstances will be, to use the words of Advocate General Jacobs, a ‘global assessment’. ( 40 )

55.

However, such a scenario was present neither in Helmig nor in Voß and in both of them the Court impliedly or explicitly paid attention to the individual components of the salary. It is thus inaccurate to differentiate those two cases, on the one hand, and Elsner-Lakeberg, on the other hand, based on the individual or less individual approach adopted by the Court. Yet, that precise perspective has been adopted by some of the parties to the present proceedings.

56.

Indeed, the approach adopted in Elsner-Lakeberg was referred to, during the present proceedings, as involving a consideration of the ‘individual components’ of the salary. Such a characterisation is rather misleading if its purpose is to distinguish the method used from the one in Helmig. As I explained above, the assessment in Helmig, and later in Voß, was no less detailed than the one carried out in Elsner-Lakeberg. In all three cases, the Court considered, in principle, the remuneration for ordinary hours and for those worked overtime. What genuinely differs between Helmig and Voß on the one hand, and Elsner-Lakeberg, on the other hand, is that, in Elsner-Lakeberg, the Court did not require that the same hours of work must always be remunerated by the same (and not a lower) salary. In contrast to Helmig (and later to Voß), that judgment impliedly accepts, as not amounting to a difference in treatment, the situation where the burden of the lower (or actually no) pay is simply alleviated for the part-time employees in proportion to their part-time situation.

57.

One may suggest that, had the Court applied the Helmig test of ‘same number of hours worked must mean same pay’ in that specific context, it would have triggered a disapplication of the national rule at issue in respect of the part-time employees. Indeed, if the same hours of work must always mean the same pay, the obligation to work without an additional pay for several hours per month could not be imposed on the part-time employees at all, or at least, not until they reached the number of full-time hours of work. That is because any such obligation imposed before the full-time threshold is reached would always result in a lower pay for the part-time employees in respect of the ‘gap’ hours (that is, hours in excess of the part-time hours and up to the full-time hours).

58.

Be that as it may, the test that resulted from the judgment in Elsner-Lakeberg is, in terms of specific outcome, incompatible with the test applied in Helmig. When deciding the case in Voß, the Court thus had to choose between those two approaches and chose that of Helmig. ( 41 ) I believe that choice can best be explained as follows.

59.

First, I note that the ‘greater burden’ test appears rather difficult to apply outside of the specific factual context of Elsner-Lakeberg. Indeed, in that case, the identified ‘burden’ was expressed in terms of a fixed number of working hours (that had to be worked before the additional pay was triggered). Arguably, one can establish quite easily the percentage that that ‘fixed burden’ represents vis-à-vis, respectively, the given part-time scheme and the full-time scheme. That exercise will, however, become much more complex if the same logic were to be transposed to a case like Voß. Indeed, in that case, the equivalent of the ‘burden’ would have to be the decreased rate of salary applicable to the ‘gap’ hours. Given that the overtime hours of work are likely to differ from month to month, the employer would be therefore working with a constantly moving target, calculating, for each month, the number of ‘gap’ hours worked by a part-time employee that could be remunerated less compared to a full-time employee.

60.

Second, and more important, I am of the view that the Court chose to apply Helmig to confirm that the possibility of a part-time employee being paid less than a full-time employee, for the same number of hours of work, is simply excluded. To lower the salary in proportion is not an option even if one could figure out a workable mathematical formula for that purpose. The reasoning and the factual result reached in Voß thus shows that the Court decided to embrace an approach to the prohibition of discrimination that offered more extensive protection to the part-time employees compared to the protection offered in Elsner-Lakeberg.

61.

On the basis of those elements, I consider that the examination of whether there is inequality in treatment of part-time employees in regard to pay should consist in verifying whether the part-time employee is receiving the same salary as a full-time employee for the same number of hours of (the same) work. That assessment must naturally involve the examination of the components of the salary when such components exist (such as the salary for ordinary work and the salary for overtime and unless the structure of the salary is too complex to be judicially reviewed), with it being understood that the examination of the individual components of the salary serves the purpose of verifying whether the salary for the same number of hours worked is the same.

62.

Following those clarifications, I shall now turn to the present case.

63.

I shall begin this section with observations on the specific nature of the part-time employment at issue (1). Then, by drawing on the discussion in the previous part of this Opinion, I will conclude that the uniformity of the trigger thresholds at issue does not lead to an inequality in treatment of part-time employees such as MK (2).

64.

It follows from the case file that MK’s profession of pilot is rather specific in that it is not subject to any fixed working hours.

65.

The defendant explained, without being contradicted by MK, that there is, in principle, certainty as to when the working day begins but little predictability as to when it ends. That is largely due to the specific nature of air traffic which makes each journey somewhat unforeseeable as delays may occur due to meteorological, operational or technical reasons. Although each journey is planned, that planning has to be, most of the time, modified. The end of each day of work is thus recorded electronically on a daily basis. It follows that the only way in which a pilot, such as MK, can work on a part-time basis, is by being granted additional days of annual leave, the result of which means that his monthly salary is proportionally reduced. However, when it comes to his actual work days, a part-time pilot works under the same conditions as a full-time pilot as regards his or her flying duty hours. Indeed, as opposed to other professions, a pilot is rarely in a position to leave his or her post of work at a specific time of the day so as to dedicate his or her time, on a regular basis, to something other than work.

66.

More specifically, the defendant explained that there are no minimum flying duty hours that a full-time or part-time pilot must attain, but there are certain maximum values that must be respected. It also explained that, for each pilot, it calculates his or her individual monthly threshold in terms of flying duty hours, which factors in a possible part-time contract and reflects the pilot’s availability for the purposes of scheduling the flights. That said, when a part-time pilot reaches his or her individual threshold as regards the flight duty hours worked, he or she is still remunerated by a salary based on the ordinary rate. It is only when he or she reaches the trigger thresholds in question that he or she is remunerated, for the hours beyond that threshold, based on the respective increased rate.

67.

From my understanding of the above, therefore, it makes little sense to distinguish, in the present context, part-time working hours, full-time working hours or overtime hours as it could be done in respect of an employee working fixed hours within the usual meaning of those terms. There are simply flying duty hours which, when exceeding the trigger thresholds at issue, are remunerated according to three progressive increased rates.

68.

The central question in this case is whether the remuneration for the ‘flying duty hours’, ( 42 ) as regards the hours worked beyond the trigger thresholds at issue, is discriminatory vis-à-vis part-time pilots, compared to full-time pilots, ( 43 ) due to the uniformity of those thresholds. As indicated above, that question has been linked by the referring court to the inquiry into whether the assessment of the situation at issue should be based on the consideration of the ‘overall pay’ or on the consideration of the components of the salary.

69.

The positions expressed in the present proceedings differ.

70.

According to MK, an assessment should be made of each component of the remuneration considered individually. The fact that the trigger thresholds are not lowered in proportion to his part-time factor infringes the prohibition of discrimination of the part-time employees. The German Government and the Commission take a similar position. ( 44 )

71.

The defendant argues to the contrary and is of the view that the assessment can rely on the test of overall pay, which, in the present case, leads to the conclusion that the uniform trigger thresholds at issue do not result in any difference in treatment. A similar position has also been taken by the Danish, Polish and Norwegian Governments. Those governments emphasise that, for the same number of flying duty hours worked, the part-time and full-time pilots receive the same salary, as required by the test established in Helmig and confirmed in Voß. Moreover, the Danish Government expressed concerns about the ramifications, across the labour market, of a possible decision to the contrary.

72.

I agree with the defendant, as well as the Danish, Polish and Norwegian Governments, that the situation at issue does not result in a difference in treatment of part-time employees.

73.

First, as regards the method to be used, I recall, in accordance with the analysis of the case-law provided above, that the assessment of the alleged discrimination of a part-time employee must consist in verifying whether, for the same number of hours (of the same work), the part-time employees receive the same salary as the full-time employees. As I also recalled, that examination must involve consideration of the individual components of the salary.

74.

In that respect, I sympathise with MK, the German Government and the Commission in so far as those parties all make the same general observations when it comes to the need to consider those individual elements. However, it follows from their pleadings that each associates that method, in principle, with the ‘greater burden test’, given that they appear to conclude that the absence of a proportionate lowering of the trigger thresholds at issue leads to a difference in treatment.

75.

Conversely, although the Danish, Polish and Norwegian Governments favour the ‘overall pay’ method, what follows from their pleadings is an acceptance towards the idea that individual components of the salary should be considered, if that consideration is still framed by the general rule, that the same hours of work must be remunerated in the same way without there being an obligation to lower the thresholds at issue in proportion to the part-time factor.

76.

With those clarifications in mind, it follows from the case file that the remuneration of the flight duty hours is the same for both categories of employees as regards the hours worked below the uniformly set trigger thresholds. The remuneration is also increased in the same way as regards the hours worked above those thresholds. It follows that, as regards each of those two components of the remuneration, the same number of the flight duty hours is remunerated by an equal pay. In the light of that rather simple mathematical exercise, I fail to see any discrimination affecting part-time pilots such as MK.

77.

As the defendant notes, unlike the situation in Voß, the provisions at issue do not result in part-time employees being paid, for any hours of their flight time duty, less than the full-time employees. As the Danish Government recalled at the hearing, the situation at issue is similar to the facts in Helmig, where the Court refused to consider as amounting to a difference in treatment the situation in which the part-time employees did not receive the salary calculated on the basis of an increased rate as of the first hour exceeding their part-time contract, when that increased rate applied for part-time and full-time employees only in excess of the equivalent of the full-time hours.

78.

Both MK and the Commission argue that the fact that the thresholds at issue are not proportionally lowered negatively affects the part-time employees as regards the relationship between the performance and the consideration received.

79.

I must admit that I find it difficult to see how exactly the negative impact should be understood given that both categories of pilots appear to be remunerated in the same manner, as regards the remuneration for hours of flying duty, for hours actually worked. Indeed, their effective performance is remunerated by the same consideration.

80.

Importantly, MK argues that there is no objective reason why the trigger thresholds should not be lowered in proportion to the part-time factor at issue given that, in his view, the provisions of the collective agreements stipulating those thresholds do not genuinely pursue the objective of compensating for a particular workload and that the values chosen for those thresholds are not supported by any objective elements. The German Government adds that MK receives a de facto lower salary than a full-time pilot because he is less likely to reach the trigger thresholds due to the fact that he works part-time.

81.

In response to those arguments, I observe, first, that the values of the trigger thresholds at issue constitute a result of an agreement reached by the social partners. Subject to compliance with the applicable regulatory limits, it is not for this Court to question it or the medical evidence on which it may rely.

82.

Second, I agree with the German Government that MK appears to work, over a period of one year, fewer hours than a full-time pilot. The likely consequence of that is that there will be fewer months during which he will reach the trigger thresholds and thus the increased remuneration for the hours of work concerned.

83.

From my understanding, to what extent that is indeed the case depends largely on the organisation of MK’s annual leave. As he confirmed at the hearing, there have indeed been months in which he was able to reach the thresholds in question. That said, even if that were not so, the relevant question in the present case is still whether, for the hours of duty flight hours actually worked, MK receives the same remuneration as a full-time pilot or whether he receives less. The reply to that question appears to be, subject to verification by the referring court, that he receives the same remuneration for the same number of hours worked.

84.

As the defendant and the Danish, Polish and Norwegian Governments have argued, to accept MK’s position would result in part-time pilots being treated better than full-time pilots as regards the number of flight duty hours exceeding their individual thresholds up to the hours of work triggering the increased rate for the full-time pilots. In the case of part-time employment at 90% of full-time working hours, that difference may be rather limited. In the case of part-time employment at 50% of full-time working hours, the difference is less so, yet the same logic would need to apply. In any event, even if the difference should concern the remuneration of only one hour of the flying duty, the correct question in the present context is not whether there is any reason why the part-time pilots should not receive such treatment as a result of the proportionate lowering of the thresholds at issue, but whether the prohibition of discrimination of part-time workers, laid down in Clause 4 of the Framework Agreement, requires such a lowering and such a treatment.

85.

As already recalled, the Framework Agreement establishes rules of minimal protection. That minimal level of protection requires, as I explained above, remuneration to be the same, and not less or more, for the same number of working hours performed by the part-time and full-time employees.

86.

It follows from the case file that MK receives, for the same number of flying duty hours, the same salary as a full-time pilot. In my view, therefore, he is not treated less favourably than a full-time pilot.

87.

In the light of the foregoing, I suggest that the Court replies to the first question referred in the present case by the Bundesarbeitsgericht (Federal Labour Court, Germany) as follows:

Clause 4.1 of the Framework Agreement on part-time work, annexed to Council Directive 97/81/EC of 15 December 1997 concerning the Framework Agreement on part-time work concluded by UNICE, CEEP and the ETUC

must be interpreted as meaning that it does not preclude a provision set out in a collective agreement, according to which additional remuneration for part-time and full-time employees is uniformly contingent on the same number of working hours having been exceeded, when the same number of hours worked by the part-time and full-time employees for the same work are remunerated by the same salary.