Mr. Burleigh presented the document GTR9-2-08 that covers several items. It was agreed in advance that the discussion on items not belonging to this agenda item will be discussed later under the respective items in the agenda.

The presentation firstly covers the details of the build levels of different impactor generations. Changes were brought-in in different phases that were explained in detail. Mr. Gehring wondered whether the appropriateness of the modifications was just confirmed by pendulum tests. This was confirmed by Mr. Burleigh.

Mr. Nguyen (NHTSA) asked how the documents of the new impactor will be dealt with, especially where data will be stored. The chair responded that this discussion had already started in Geneva and Humanetics is aware of the fact that the documentation needs to be stored in a public area.

Also, Mr. Nguyen was wondering whether the detailed measurement data can be shared. Dr. Ries (OICA) asked if the question refers to the raw data which was confirmed. Dr. Konosu confirmed that JARI is willing to provide their certification test data obtained at JARI. The chair asked whether industry can also share the detailed data of the vehicle tests. OICA will check this. Mr. Nguyen promised that NHTSA also will share their detailed data since this then allows a good comparison of the overall performance of the impactors.

In the second part, the presentation explains how the changes of the legforms’ build levels are recorded to assure that they can be tracked.

The third part of the document compares the effects of filtering test results with filter classes CFC 180 with those with using CFC 600 filters. Mr. Burleigh stated that the use of the different filter classes does not influence the test results significantly in general but obviously has an influence on the acceleration.

Mr. Hess asked what the numbering of the bone batches means. Mr. Burleigh responded that the bone core material is received from the manufacturer of the material in different batches. However, the detailed differences are not known but the bone core manufacturer confirmed that there are differences. Humanetics therefore conducts fine-tuning regarding the bone core bending stiffnesses one by one in the process of reducing bone core thickness from original one.

Mr. Zander presented the experiences of three years of inverse certification testing with the prototype legform SN-02 (see document GTR9-2-04).

Dr. Otubushin asked whether BASt has an explanation for the decay of the test results in the 2nd test reported. Mr. Zander replied that they do not have such an explanation. Dr. Otubushin also wondered what the reasons for the large scatter in the rebound phase of the impactor may be: while the test results show good repeatability for the first peak the scatter becomes up to 50% during the rebound phase and seems to be uncontrollable. Dr. Otubuhsin added that this should not be seen as criticism against the legform but that needs to be considered for the assessment of the vehicle results.

Ms. Chaka asked for clarification of the changes to the impactor in between the tests. Mr. Zander replied that only very limited changes were done, only the string pots were replaced and it needs to be added that the length of the rubber has changed some when during the tests. Mr. Pingston added that this is a good study but due to the fact that SN-02 still has polyester bone core material it may be outdated. Mr. Zander and Mr. Gehring offered to do a similar assessment for SN-04 provided that all certification data will be made available by the owners of the data. Messrs. Zander and Gehring will try to get the respective approvals.

Dr. Ries wondered why some of the early tests results are shown as non-compliant despite the data produced with this legform were also used for the definition of the certification corridors. Mr. Zander confirmed that some of the test results were not considered since they were considered to be outliers of a larger number of test results.

The chair added that following the long-time experiences reported by OICA during the past meeting Humanetics proposed to add screw holes to tighten some screws that were found to be lose (see one section in document GTR9-2-08). Mr. Burleigh highlighted that this will work for the femur section but will not work to the tibia section due to a wire that is fitted there. Dr. Konosu recommended to not apply this change but to recommend in the PADI that this should be inspected in defined intervals and how this can be done. This was finally agreed.