Text in force at CS27-10: from CS27-0, effective 14 Nov 2003.
(a) It must be impossible for the tail rotor to contact the landing surface during a normal landing.
(b) If a tail rotor guard is required to show compliance with sub-paragraph (a):
(1) Suitable design loads must be established for the guard; and
(2) The guard and its supporting structure must be designed to withstand those loads.
ED Decision 2003/015/RM · Source