Seat Adjustment. 3.1.4.1. The seat shall be set as specified by the manufacturer, with regard to both the design position of the seat back (see paragraph 2.21. of this Regulation) and the position of the seat itself. This position shall be the one where the H-point coincides with R50 point. In the absence of any specification declared by the manufacturer, the procedures of paragraphs 3.1.4.2. to 3.1.4.5. shall apply.
3.1.4.2. Where no adjustment is specified, the seat shall be adjusted to its mid-position in both the horizontal and vertical directions. If an adjustment position does not exist midway between those positions, place the seat midway between the most forward and most rearward position. The closest adjustment position to the rear of the midpoint shall be used.
3.1.4.3. Where no cushion adjustment is specified, and where the seat cushion is adjustable independently of the seat back, adjust the seat cushion inclination to its mid-position. All other cushion adjustments shall be in a fully retracted position, with the exception of cushion side bolsters which shall be set to their widest position.
3.1.4.4. Any adjustable lumbar supports shall be positioned so that the lumbar support is in its lowest retracted or deflated position. Arm rests shall be set in the stowed position.
3.1.4.5. Any other seat adjustment device must be set in it most retracted or deflated position.
3.1.4.6. Where no design torso angle is specified and where the seat back is adjustable, it shall be set at a torso angle closest to 25º ±1º from the vertical, as measured using the three-dimensional H-point machine, as specified in Annex 3. If there is more than one inclination position close to a torso angle of 25 º then it shall be set to the position closest to and rearward of 25 º.
