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Federal Aviation Administration, DOT 

§ 29.1335 

§ 29.1329

Automatic pilot system. 

(a) Each automatic pilot system 

must be designed so that the automatic 
pilot can— 

(1) Be sufficiently overpowered by 

one pilot to allow control of the rotor-
craft; and 

(2) Be readily and positively dis-

engaged by each pilot to prevent it 
from interfering with the control of the 

(b) Unless there is automatic syn-

chronization, each system must have a 
means to readily indicate to the pilot 
the alignment of the actuating device 
in relation to the control system it op-

(c) Each manually operated control 

for the system’s operation must be 
readily accessible to the pilots. 

(d) The system must be designed and 

adjusted so that, within the range of 
adjustment available to the pilot, it 
cannot produce hazardous loads on the 
rotorcraft, or create hazardous devi-
ations in the flight path, under any 
flight condition appropriate to its use, 
either during normal operation or in 
the event of a malfunction, assuming 
that corrective action begins within a 
reasonable period of time. 

(e) If the automatic pilot integrates 

signals from auxiliary controls or fur-
nishes signals for operation of other 
equipment, there must be positive 
interlocks and sequencing of engage-
ment to prevent improper operation. 

(f) If the automatic pilot system can 

be coupled to airborne navigation 
equipment, means must be provided to 
indicate to the pilots the current mode 
of operation. Selector switch position 
is not acceptable as a means of indica-

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as 
amended by Amdt. 29–24, 49 FR 44439, Nov. 6, 
1984; Amdt. 29–24, 49 FR 47594, Dec. 6, 1984; 
Amdt. 29–42, 63 FR 43285, Aug. 12, 1998] 

§ 29.1331

Instruments using a power 


For category A rotorcraft— 
(a) Each required flight instrument 

using a power supply must have— 

(1) Two independent sources of power; 
(2) A means of selecting either power 

source; and 

(3) A visual means integral with each 

instrument to indicate when the power 

adequate to sustain proper instrument 
performance is not being supplied. The 
power must be measured at or near the 
point where it enters the instrument. 
For electrical instruments, the power 
is considered to be adequate when the 
voltage is within the approved limits; 

(b) The installation and power supply 

system must be such that failure of 
any flight instrument connected to one 
source, or of the energy supply from 
one source, or a fault in any part of the 
power distribution system does not 
interfere with the proper supply of en-
ergy from any other source. 

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as 
amended by Amdt. 29–24, 49 FR 44439, Nov. 6, 

§ 29.1333

Instrument systems. 

For systems that operate the re-

quired flight instruments which are lo-
cated at each pilot’s station, the fol-
lowing apply: 

(a) Only the required flight instru-

ments for the first pilot may be con-
nected to that operating system. 

(b) The equipment, systems, and in-

stallations must be designed so that 
one display of the information essen-
tial to the safety of flight which is pro-
vided by the flight instruments re-
mains available to a pilot, without ad-
ditional crewmember action, after any 
single failure or combination of fail-
ures that are not shown to be ex-
tremely improbable. 

(c) Additional instruments, systems, 

or equipment may not be connected to 
the operating system for a second pilot 
unless provisions are made to ensure 
the continued normal functioning of 
the required flight instruments in the 
event of any malfunction of the addi-
tional instruments, systems, or equip-
ment which is not shown to be ex-
tremely improbable. 

[Amdt. 29–24, 49 FR 44439, Nov. 6, 1984] 

§ 29.1335

Flight director systems. 

If a flight director system is in-

stalled, means must be provided to in-
dicate to the flight crew its current 

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