(a) It must be shown by analysis, test, or both, that the rotorcraft
external load attaching means for rotorcraft-load combinations to be used
for nonhuman external cargo applications can withstand a limit static load
equal to 2.5, or some lower load factor approved under §§29.337 through
29.341, multiplied by the maximum external load for which authorization is
requested. It must be shown by analysis, test, or both that the rotorcraft
external load attaching means and corresponding personnel carrying device
system for rotorcraft-load combinations to be used for human external
cargo applications can withstand a limit static load equal to 3.5 or some
lower load factor, not less than 2.5, approved under §§29.337 through
29.341, multiplied by the maximum external load for which authorization is
requested. The load for any rotorcraft-load combination class, for any
external cargo type, must be applied in the vertical direction. For
jettisonable external loads of any applicable external cargo type, the
load must also be applied in any direction making the maximum angle with
the vertical that can be achieved in service but not less than 30°.
However, the 30° angle may be reduced to a lesser angle if --
(1) An operating limitation is established limiting external load
operations to such angles for which compliance with this paragraph has
been shown; or
(2) It is shown that the lesser angle can not be exceeded in service.
(b) The external load attaching means, for jettisonable rotorcraft-load
combinations, must include a quick-release system to enable the pilot to
release the external load quickly during flight. The quick-release system
must consist of a primary quick release subsystem and a backup quick
release subsystem that are isolated from one another. The quick release
system, and the means by which it is controlled, must comply with the
following:
(1) A control for the primary quick release subsystem must be installed
either on one of the pilot's primary controls or in an equivalently
accessible location and must be designed and located so that it may be
operated by either the pilot or a crewmember without hazardously limiting
the ability to control the rotorcraft during an emergency situation.
(2) A control for the backup quick release subsystem, readily
accessible to either the pilot or another crewmember, must be provided.
(3) Both the primary and backup quick release subsystems must --
(i) Be reliable, durable, and function properly with all external loads
up to and including the maximum external limit load for which
authorization is requested.
(ii) Be protected against electromagnetic interference (EMI) from
external and internal sources and against lightning to prevent inadvertent
load release.
(A) The minimum level of protection required for jettisonable
rotorcraft-load combinations used for nonhuman external cargo is a radio
frequency field strength of 20 volts per meter.
(B) The minimum level of protection required for jettisonable
rotorcraft-load combinations used for human external cargo is a radio
frequency field strength of 200 volts per meter.
(iii) Be protected against any failure that could be induced by a
failure mode of any other electrical or mechanical rotorcraft system.
(c) For rotorcraft-load combinations to be used for human external
cargo applications, the rotorcraft must --
(1) For jettisonable external loads, have a quick-release system that
meets the requirements of paragraph (b) of this section and that --
(i) Provides a dual actuation device for the primary quick release
subsystem, and
(ii) Provides a separate dual actuation device for the backup quick
release subsystem;
(2) Have a reliable, approved personnel carrying device system that has
the structural capability and personnel safety features essential for
external occupant safety;
(3) Have placards and markings at all appropriate locations that
clearly state the essential system operating instructions and, for the
personnel carrying device system, ingress and egress instructions;
(4) Have equipment to allow direct intercommunication among required
crewmembers and external occupants;
(5) Have the appropriate limitations and procedures incorporated in the
flight manual for conducting human external cargo operations; and
(6) For human external cargo applications requiring use of Category A
rotorcraft, have one-engine-inoperative hover performance data and
procedures in the flight manual for the weights, altitudes, and
temperatures for which external load approval is requested.
(d) The critically configured jettisonable external loads must be shown
by a combination of analysis, ground tests, and flight tests to be both
transportable and releasable throughout the approved operational envelope
without hazard to the rotorcraft during normal flight conditions. In
addition, these external loads -- must be shown to be releasable without
hazard to the rotorcraft during emergency flight conditions.
(e) A placard or marking must be installed next to the external-load
attaching means clearly stating any operational limitations and the
maximum authorized external load as demonstrated under §29.25 and this
section.
(f) The fatigue evaluation of §29.571 of this part does not apply to
rotorcraft-load combinations to be used for nonhuman external cargo except
for the failure of critical structural elements that would result in a
hazard to the rotorcraft. For rotorcraft-load combinations to be used for
human external cargo, the fatigue evaluation of §29.571 of this part
applies to the entire quick release and personnel carrying device
structural systems and their attachments.