(3)
Where .oorrailsor .oororsidewall.oorattachmentdevicesareusedtoattach the seating devices to the airframe structure for the conditions of this section, the rails or devices must be misaligned with respect to each other by at least
''
10vertically(i.e.,pitch outofparallel) andby atleasta10lateral roll,with the directions optional, to account for possible .oor warp.
(c) Compliance with the following must be shown :
(1)
The seating device system must remain intact although it may experience separation intended as part of its design.
(2)
The attachment between the seating device and the airframe structure must remain intact, although the structure may have exceeded its limit load.
(3)
The ATD’s shoulder harness strap or straps must remain on or in the imme-diate vicinity of the ATD’s shoulder during the impact.
(4)
The safety belt must remain on the ATD’s pelvis during the impact.
(5)
TheATD’shead eitherdoes not contact anyportion of the crew orpassenger compartment, or if contact is made, the head impact does not exceed a head injury criteria(HIC) of1,000 asdeterminedby this equation.
4
t2
1
HIC =(t2 .t1) a(t)dt 2.5
(t2 .t1) t1
Where : a(t)is the resultant acceleration at the center of gravity of the head form expressed as a multiple ofg(the acceleration ofgravity) and t2.t1 is the time duration, in seconds, of major head impact, not to exceed 0.05 seconds.
(6)
Loads in individual shoulder harness straps must not exceed 1,750 pounds. If dual straps are used for retaining the upper torso, the total harness strap loads must not exceed2,000pounds.
(7)
The maximum compressive load measured between the pelvis and the lumbar column oftheATD must not exceed1,500pounds.
(d) An alternate approach that achieves an equivalent orgreaterlevel of occupantpro-
tection, as required by this section, must be substantiated on a rational basis.] Amdt. 27-25, E.. 12/13/89
′
Elodie Roux. Septembre 2003
Subpart C : Strength Requirements
FAR 27.563 : Structural ditching provisions
[Ifcerti.cation withditchingprovisionsis requested, structural strengthforditching must meet the requirements of this section and Sec. 27.801(e).
(a)
Forward speed landing conditions. The rotorcraft must initially contact the most critical wave for reasonably probable water conditions at forward velocities from zero up to 30 knots in likely pitch, roll, and yaw attitudes. The rotorcraft limit vertical descent velocity may not be less than 5 feet per second relative to the mean water surface. Rotor lift may be used to act through the center of gravity throughout the landing impact. This lift may not exceed two-thirds of the design maximum weight. A maximum forward velocity of less that 30 knots may be used in design if it can be demonstrated that the forward velocity selected would not be exceeded in a normal one-engine-out touchdown.
(b)
Auxiliary or emergency .oat conditions.
(1)
Floats .xed or deployed before initial water contact. In addition to the landing loadsinparagraph(a) of thissection,each auxiliary oremergency.oat,orits support and attaching structure in the airframe or fuselage, must be designed for the load developed by a fully immersed .oat unless it can be shown that full immersion is unlikely. If full immersion is unlikely, the highest likely .oat buoyancy load must be applied. The highest likely buoyancy load must in-clude consideration of a partially immersed .oat creating restoring moments to compensate the upsetting moments caused by side wind, unsymmetrical rotorcraft loading, water wave action, rotorcraft inertia, and probable struc-tural damage and leakage considered underSec. 27.801(d).Maximum roll and pitch angles determined from compliance with Sec. 27.801(d) may be used, if signi.cant, to determine the extent of immersion of each .oat. If the .oats aredeployedin .ight,appropriateairloadsderivedfromthe .ightlimitations with the .oats deployed shall be used in substantiation of the .oats and their attachment to the rotorcraft. For this purpose, the design airspeed for limit load is the .oat deployed airspeed operating limit multiplied by 1.11.
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 4(83)
