In T 1028/96 of 15.9.1999, an objection by a party that a member of the board had previously "participated in the decision under appeal" (Art. 24(1) EPC 1973) only covered decisions of the examining and opposition divisions and not decisions of the boards of appeal arising from those decisions. An objection under Art. 24(3) EPC 1973 based on "suspected partiality" could give rise to exclusion of board members originally appointed in circumstances where substantially the same crucial facts were at issue in opposition appeal proceedings as had previously been at issue in grant appeal proceedings "in the light of the particular circumstances of each individual case".
In J 15/04, with regard to the intention of Art. 24 EPC 1973, the board considered whether or not it would be appropriate to exclude a member of the board from proceedings whenever he had played any role in a previous case which had any functional coherence with the one under consideration. Such functional coherency could be seen in the relationship of a divisional application to its parent application, as in the procedural situation at issue.
The board noted that it was self-explanatory that in cases where a specific board of appeal decided the same legal question in every case in an identical way, an exclusion of the members of this board could not be petitioned, even if a party had already "suffered from" such a decision, although a functional coherency of these cases could not be denied. Otherwise any established jurisprudence of a board would lead to a permanent exclusion of its members whenever the same legal question was at stake. The opposite view would endanger the judicial efficiency of the boards of appeal. It was to be noted that the principle of judicial efficiency also constituted an essential element of the right to a fair trial and outweighed any allegation concerning a generally "possible" suspicion of partiality which was not based on the specific facts of the case currently under appeal.
By the same token, the principle of a fair trial did not generally exclude a member of the boards of appeal from dealing with a party's case repeatedly, as might happen when a board referred a case back to the first instance and the appeal from the following decision established the competence of the same board composed of the former members who had taken the first decision. As a result of these considerations, the board held that any broader interpretation of the wording "participated in the decision under appeal" pursuant to Art. 24(1) EPC 1973 had to be based on the occurrence of specific facts of the case to be decided which were sufficient to raise specific concrete doubts as to the board member's ability to hear the appeal with an objective judicial mind and could not be concluded from the mere procedural fact that a member of the board had already been involved in former proceedings with the same party or the same legal. The essence of Art. 24(1) EPC 1973 was not to establish an assumption that any former involvement of a member of the board in a case dealing with the interests of a specific party established a possible suspicion of partiality of that member in all subsequent cases, but was specifically to exclude the participation of this member in reviewing a decision under appeal which had been dealt with by himself as part of the deciding body.
In the case at issue, the board stated that the exclusion of the originally appointed chairman could be required under the terms of Art. 24(1) EPC 1973, if he had participated in the decision under appeal. It held that according to the wording of this provision, the exclusion of the originally appointed chairman was obviously not justified because the decision under appeal was different from the decision refusing the parent application. As a result, the board found that Art. 24(1) EPC 1973 did not apply to the appeal and that therefore the originally appointed chairman was not excluded from deciding on the subject-matter of the appeal.