FAA Federal Aviation Regulations (FARS, 14 CFR)

C23.1 Basic landing conditions

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Tail wheel type                              Nose wheel type
                                     -------------------------------------------------------------------------------------------------------------------
Condition                                                                                                  Level landing with
                                     Level landing           Tail-down landing       Level landing with    nose wheel just clear  Tail-down landing
                                                                                     inclined reactions    of ground
--------------------------------------------------------------------------------------------------------------------------------------------------------
Reference section..................  23.479(a)(1)..........  23.481(a)(1)..........  23.479(a)(2)(i)...... 23.479(a)(2)(ii).....  23.481(a)(2) and (b).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vertical component at c. g.........  nW....................  nW....................  nW................... nW...................  nW.
Fore and aft component at c. g.....  KnW...................  0.....................  KnW.................. KnW..................  0.
Lateral component in either          0.....................  0.....................  0.................... 0....................  0.
direction at c. g.
Shock absorber extension (hydraulic  Note (2)..............  Note (2)..............  Note (2).............  Note(2).............  Note (2).
shock absorber).
Shock absorber deflection (rubber    100...................  100...................  100.................. 100..................  100.
or spring shock absorber), percent.
Tire deflection....................  Static................  Static................  Static............... Static...............  Static.
Main wheel loads (both wheels) (Vr)  (n-L)W................  (n-L)W b/d............  (n-L)W a[prime]/      (n-L)W...............  (n-L)W.
d[prime].
Main wheel loads (both wheels) (Dr)  KnW...................  0.....................  KnW a[prime]/d[prime] KnW..................  0.
Tail (nose) wheel loads (Vf).......  0.....................  (n-L)W a/d............  (n-L)W b[prime]/      0....................  0.
d[prime].
Tail (nose) wheel loads (Df).......  0.....................  0.....................  KnW b[prime]/d[prime] 0....................  0.
Notes..............................  (1), (3), and (4).....  (4)...................  (1)..................  (1), (3), and (4)...  (3) and (4).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note (1). K may be determined as follows: K=0.25 for W=3,000 pounds or less; K=0.33 for W=6,000 pounds or greater, with linear variation of K between
these weights.
Note (2). For the purpose of design, the maximum load factor is assumed to occur throughout the shock absorber stroke from 25 percent deflection to 100
percent deflection unless otherwise shown and the load factor must be used with whatever shock absorber extension is most critical for each element of
the landing gear.
Note (3). Unbalanced moments must be balanced by a rational or conservative method.
Note (4). L is defined in § 23.735(b).
Note (5). n is the limit inertia load factor, at the c.g. of the airplane, selected under § 23.473 (d), (f), and (g).