Проблема в том, что вы не понимаете что именно написано в этом пп.
У европейцев чуть лучше дело поставлено - у них помимо самих требований есть еще такая важная вещь, как AMC.
AMC 25.561 - General
ED Decision 2003/2/RM
In complying with the provisions of CS 25.561(b) & (c), the loads arising from the restraint of seats and items of equipment etc. should be taken into the structure to a point where the stresses can be dissipated (e.g. for items attached to the fuselage floor, the load paths from the attachments through to the fuselage primary structure should be taken into account).
AMC 25.561(b)(3) - Commercial Accommodation Equipment
ED Decision 2011/004/R
Commercial accommodation equipment complying only with FAR 25.561 pre-Amendment 25-91 need additional substantiation by analysis, tests or combination thereof to cover the 1·33 factor for their attachments as specified in CS 25.561(c). [Amdt 25/11]
AMC 25.561(d) - General
ED Decision 2003/2/RM
For the local attachments of seats and items of mass it should be shown by analysis and/or tests that under the specified load conditions, the intended retaining function in each direction is still available.
Читайте, изучайте.
ЗЫ. И кстати, обратите внимание - при аварийной посадке шасси должно быть убрано (если оно вообще убирается, понятное дело)