Federal Aviation Administration, DOT

Section 25.1435

MISCELLANEOUS EQUIPMENT

Element

Section 25.1431 Electronic equipment.
(a) In showing compliance with
Section 25.1309 (a) and (b) with respect to
radio and electronic equipment and
their installations, critical environmental conditions must be considered.
(b) Radio and electronic equipment
must be supplied with power under the
requirements of Section 25.1355(c).
(c) Radio and electronic equipment,
controls, and wiring must be installed
so that operation of any one unit or
system of units will not adversely affect the simultaneous operation of any
other radio or electronic unit, or system of units, required by this chapter.
(d) Electronic equipment must be designed and installed such that it does
not cause essential loads to become inoperative as a result of electrical
power supply transients or transients
from other causes.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-113, 69 FR 12530, Mar.
16, 2004]

Section 25.1433 Vacuum systems.
There must be means, in addition to
the normal pressure relief, to automatically relieve the pressure in the
discharge lines from the vacuum air
pump when the delivery temperature of
the air becomes unsafe.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-72, 55 FR 29785, July 20,
1990]

Section 25.1435 Hydraulic systems.
(a) Element design. Each element of
the hydraulic system must be designed
to:
(1) Withstand the proof pressure
without permanent deformation that
would prevent it from performing its
intended functions, and the ultimate
pressure without rupture. The proof
and ultimate pressures are defined in
terms of the design operating pressure
(DOP) as follows:
Proof
(xDOP)

spaschal on DSK3GDR082PROD with CFR

Element
1. Tubes and fittings. .........................
2. Pressure vessels containing gas:
High pressure (e.g., accumulators) .........................................
Low pressure (e.g., reservoirs) ..
3. Hoses ............................................

Ultimate
(xDOP)

1.5

3.0

3.0
1.5
2.0

4.0
3.0
4.0

4. All other elements .........................

Proof
(xDOP)
1.5

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(2) Withstand, without deformation
that would prevent it from performing
its intended function, the design operating pressure in combination with
limit structural loads that may be imposed;
(3) Withstand, without rupture, the
design operating pressure multiplied by
a factor of 1.5 in combination with ultimate structural load that can reasonably occur simultaneously;
(4) Withstand the fatigue effects of
all cyclic pressures, including transients, and associated externally induced loads, taking into account the
consequences of element failure; and
(5) Perform as intended under all environmental conditions for which the
airplane is certificated.
(b) System design. Each hydraulic system must:
(1) Have means located at a
flightcrew station to indicate appropriate system parameters, if
(i) It performs a function necessary
for continued safe flight and landing;
or
(ii) In the event of hydraulic system
malfunction, corrective action by the
crew to ensure continued safe flight
and landing is necessary;
(2) Have means to ensure that system
pressures, including transient pressures and pressures from fluid volumetric changes in elements that are
likely to remain closed long enough for
such changes to occur, are within the
design capabilities of each element,
such that they meet the requirements
defined in Section 25.1435(a)(1) through (a)(5);
(3) Have means to minimize the release of harmful or hazardous concentrations of hydraulic fluid or vapors
into the crew and passenger compartments during flight;
(4) Meet the applicable requirements
of SectionSection 25.863, 25.1183, 25.1185, and 25.1189 if
a flammable hydraulic fluid is used;
and
(5) Be designed to use any suitable
hydraulic fluid specified by the airplane manufacturer, which must be
identified by appropriate markings as
required by Section 25.1541.

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(xDOP)

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