Federal Aviation Administration, DOT

Pt. 135, App. A

(2) At speeds between Vmo and Vc, the loads
resulting from the disconnection of the engine compressor from the turbine or from
loss of the turbine blades are considered to
be ultimate loads.
(3) The time history of the thrust decay
and drag buildup occurring as a result of the
prescribed engine failures must be substantiated by test or other data applicable to the
particular engine-propeller combination.
(4) The timing and magnitude of the probable pilot corrective action must be conservatively estimated, considering the characteristics of the particular engine-propeller-airplane combination.
(b) Pilot corrective action may be assumed
to be initiated at the time maximum yawing
velocity is reached, but not earlier than 2
seconds after the engine failure. The magnitude of the corrective action may be based
on the control forces in FAR 23.397 except
that lower forces may be assumed where it is
shown by analysis or test that these forces
can control the yaw and roll resulting from
the prescribed engine failure conditions.
Ground Loads
27. Dual wheel landing gear units. Each dual
wheel landing gear unit and its supporting
structure must be shown to comply with the
following:
(a) Pivoting. The airplane must be assumed
to pivot about one side of the main gear with
the brakes on that side locked. The limit
vertical load factor must be 1.0 and the coefficient of friction 0.8. This condition need
apply only to the main gear and its supporting structure.
(b) Unequal tire inflation. A 60-40 percent
distribution of the loads established under
FAR 23.471 through FAR 23.483 must be applied to the dual wheels.
(c) Flat tire. (1) Sixty percent of the loads
in FAR 23.471 through FAR 23.483 must be applied to either wheel in a unit.
(2) Sixty percent of the limit drag and side
loads and 100 percent of the limit vertical
load established under FARs 23.493 and 23.485
must be applied to either wheel in a unit except that the vertical load need not exceed
the maximum vertical load in paragraph
(c)(1) of this section.
Fatigue Evaluation
28. Fatigue evaluation of wing and associated
structure. Unless it is shown that the structure, operating stress levels, materials and
expected use are comparable from a fatigue
standpoint to a similar design which has had
substantial satisfactory service experience,
the strength, detail design, and the fabrication of those parts of the wing, wing carrythrough, and attaching structure whose failure would be catastrophic must be evaluated
under either - 

(a) A fatigue strength investigation in
which the structure is shown by analysis,
tests, or both to be able to withstand the repeated loads of variable magnitude expected
in service; or
(b) A fail-safe strength investigation in
which it is shown by analysis, tests, or both
that catastrophic failure of the structure is
not probable after fatigue, or obvious partial
failure, of a principal structural element,
and that the remaining structure is able to
withstand a static ultimate load factor of 75
percent of the critical limit load factor at VC.
These loads must be multiplied by a factor of
1.15 unless the dynamic effects of failure
under static load are otherwise considered.
Design and Construction
29. Flutter. For multiengine turbopropeller
powered airplanes, a dynamic evaluation
must be made and must include - 
(a) The significant elastic, inertia, and aerodynamic forces associated with the rotations and displacements of the plane of the
propeller; and
(b) Engine-propeller-nacelle stiffness and
damping variations appropriate to the particular configuration.
Landing Gear
30. Flap operated landing gear warning device. Airplanes having retractable landing
gear and wing flaps must be equipped with a
warning device that functions continuously
when the wing flaps are extended to a flap
position that activates the warning device to
give adequate warning before landing, using
normal landing procedures, if the landing
gear is not fully extended and locked. There
may not be a manual shut off for this warning device. The flap position sensing unit
may be installed at any suitable location.
The system for this device may use any part
of the system (including the aural warning
device) provided for other landing gear warning devices.
Personnel and Cargo Accommodations
31. Cargo and baggage compartments. Cargo
and baggage compartments must be designed
to meet FAR 23.787 (a) and (b), and in addition means must be provided to protect passengers from injury by the contents of any
cargo or baggage compartment when the ultimate forward inertia force is 9g.
32. Doors and exits. The airplane must meet
FAR 23.783 and FAR 23.807 (a)(3), (b), and (c),
and in addition:
(a) There must be a means to lock and
safeguard each external door and exit
against opening in flight either inadvertently by persons, or as a result of mechanical failure. Each external door must be operable from both the inside and the outside.
(b) There must be means for direct visual
inspection of the locking mechanism by

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